Answer:
endothermic reaction
Explanation:
When Elsa from Frozen freezes things, it is an example of an endothermic chemical reaction.
An endothermic involves a reaction in which heat is absorbed from the surrounding. Hence the surrounding becomes colder at the end of the the change.
So, Elsa draws heat from the environment and this causes the environment to be colder and things that are in contact with her.
7.34g of metal A changes in temperature from 41.4°C to 54.7°C and
absorbs 923.5J in the process. Calculate the specific heat of metal A
9.46 J/g °C
General Formulas and Concepts:Chemistry
Thermodynamics
Specific Heat Formula: q = mcΔT
q is heat (in J)m is mass (in g)c is specific heat (in J/g °C)ΔT is change in temperature (in °C or K)Math
Pre-Algebra
Order of Operations: BPEMDAS
BracketsParenthesisExponentsMultiplicationDivisionAdditionSubtractionLeft to RightEquality Properties
Multiplication Property of EqualityDivision Property of EqualityAddition Property of EqualitySubtraction Property of EqualityExplanation:Step 1: Define
Identify variables
[Given] m = 7.34 g
[Given] q = 923.5 J
[Given] ΔT = 54.7 °C - 41.4 °C = 13.3 °C
[Solve] c
Step 2: Solve for c
Substitute in variables [Specific Heat Formula]: 923.5 J = (7.34 g)c(13.3 °C)Multiply: 923.5 J = (97.622 g °C)c[Division Property of Equality] Divide 97.622 g °C on both sides: 9.45996 J/g °C = cRewrite: c = 9.45996 J/g °CStep 3: Check
Follow sig fig rules and round. We are given 3 sig figs as our lowest.
9.45966 J/g °C ≈ 9.46 J/g °C
Topic: AP Chemistry
Unit: Thermodynamics
Book: Pearson AP Chemistry
Why is it necessary to keep the total number of drops in the test tubes
consistent?
Answer:
I don't know if this is right but..
Explanation:
It is important to keep the volume of the reactant constant because it ensures that the temperature change was the result of the reactants consumed
Why it is necessary to keep the to drops in the test tubes consistent is:
To be able to achieve your desire results, it is imperative that you follow the procedure and use the drops specified because any other drop may shift the equilibrium to the right and this will increase the rate of reaction leading to more collisions of that reactant in a specific time period and therefore alter (slow or increase) the chemical reaction.In a chemical reaction, the reactants, are undergoing chemical reaction which therefore brings about a products. The reaction rate shows how quickly or slowly the reaction takes place.Conclusively, Why it is necessary to keep the to drops in the test tubes consistent is:
To be able to achieve your desire results, it is imperative that you follow the procedure and use the drop specified because any other drop may shift the equilibrium to the right and this will increase the rate of reaction leading to more collisions of that reactant in a specific time period.Learn more from
https://brainly.com/question/14197404
All voltmeters have two probes attached to make a measurement explain why you cannot make a voltmeter with a single probe to measure the voltage of a wire
As voltages is a potential in relation to a reference, one probe must be on the reference or "zero" planes and the other must be on the point being measured.
Why does a voltmeter not accurately read voltage?because the voltmeter uses some of the main circuit's current. Main present in the circuit diminishes as a result, and the voltmeter's reading of the potential difference does not correspond to its true value.
Why are there two probes on a voltmeter?Nothing is measured at a specific point by the voltmeter. It gauges the voltage (V) differential between two circuit locations. Thus, a multimeter has two leads rather than one.
To know more about measured visit:
https://brainly.com/question/28370017
#SPJ1
Pickles are made by soaking cucumbers in a mixture of
table salt (sodium chloride), water, and spices. If you
place a cathode and anode at either end of the pickle, it
will light up. Why does this happen, and why won' the
experiment work if you plug in a plain cucumber instead?
Ions can be made by single element or covalently bonded group of elements. The covalently bonded group of elements is called polyatomic ions or polyatomic atoms. Therefore, the reason for the generation of electricity is the freely moving ions from the salt sodium chloride.
What is Ions?Any species that contain charge whether it is positive charge or negative charge is called ions. The example of polyatomic ions are sulfate, phosphate, nitrate etc.
Cation is the species that loose electron and attain positive charge while anion is a species which gain electron and attains negative charge so when anion and cation combine in fixed ration the the overall charge of the molecule is zero that is molecule is neutral, the charge over cation and anion is also called oxidation state.
Pickles are made by soaking cucumbers in a mixture of table salt (sodium chloride), water, and spices. If you place a cathode and anode at either end of the pickle, it will light up. The reason for the generation of electricity is the freely moving ions from the salt sodium chloride.
Therefore, the reason for the generation of electricity is the freely moving ions from the salt sodium chloride.
To learn more about ions, here:
https://brainly.com/question/13692734
#SPJ2
A graduated cylinder contains 50.0 ml of water. A 23.5 g piece of unknown metal is carefully dropped into the cylinder. When
the metal is completely covered with water, the water rises to the 53.4 ml mark. What is the density of the unknown piece of
metal in g/ml?
To find the density of the unknown piece of metal, we can use the formula:
Density = mass / volume.
How to find the density ?The volume of the metal can be calculated by deducting the starting water volume (50.0 ml) from the final water volume (53.4 ml) after the metal is introduced. We know the mass of the unknown metal is 23.5 g.Volume of metal = 53.4 ml - 50.0 ml = 3.4 ml.Now we can substitute the values into the density formula: Density = 23.5 g / 3.4 ml = 6.9 g/ml.Therefore, the density of the unknown piece of metal is 6.9 g/ml.To know more about density , check out :
https://brainly.com/question/1354972
#SPJ1
Is the formula of both copper (1) superoxide and copper (2) peroxide CuO2?
Answer:
Copper(2+) is an ion of copper carrying a double positive charge. It has a role as a cofactor. It is a divalent metal cation, a copper cation and a monoatomic dication. Oxidation means loss of electron and reduction means gain of electron. In this case Cu donates 2 electrons to form Cu^2+ ion,therefore,its an oxidation process.
Explanation:
Which of the following sequences describes how a four-stroke engine cycle
powers the engine?
O A. Expansion, air and fuel intake, compression and ignition,
extinguishment
B. Air and fuel intake, compression and ignition, combustion and
expansion, exhaust
O C. Hydrogen and fuel intake, expansion, compression and ignition,
exhaust
O D. Contraction, compression and ignition, air and fuel intake, exhaust
The sequence which describes the four-stroke engine cycle is air and fuel intake, compression and ignition, combustion and expansion, exhaust.
What is four stroke engine cycle?Four stroke engine cycle is a type of engine in which internal combustion takes place by the piston.
Stroke in the engine stands for the whole travel of piston along the cylinder. Following are the sequence of processes that occur in the engine:
Injection: In this process air and fuel are injected to the engine.Ignition: The intake material will compressed and ignition of them takes place.Combustion: As a result of the ignition, combustion of the fuel takes place and due to the formation of products from the combustion reaction again expansion takes place.Exhaust: In this step piston pushes out burned gases from the engine.Hence, correct sequence is air and fuel intake, compression and ignition, combustion and expansion, exhaust.
To know more about 4-stroke engine, visit the below link:
https://brainly.com/question/16195593
#SPJ1
Mg(s) + Ni2+(ag) -> Mg2+ (aq) + Ni(s) What is the total number of moles of electrons lost by Mg(s) when 2.0 moles of electrons are gained by Ni2+(ag)? * 10 ( 1.0 mol ,20 mol ,3.0 mol, 4.0 mol
The total number of moles of electrons lost by Mg(s) when 2.0 moles of electrons are gained by Ni2+(ag) is also 2.0 moles of electrons.
How to find the number of moles?This is because in a chemical equation, the number of moles of electrons gained by the reducing agent (in this case Ni2+) is equal to the number of moles of electrons lost by the oxidizing agent (in this case Mg(s)).
In this redox reaction, Mg is being oxidized because it loses electrons and Ni is being reduced because it gains electrons. The oxidation and reduction process are occurring simultaneously, so the number of electrons lost by Mg(s) is equal to the number of electrons gained by Ni2+(ag).
Learn more about moles of electrons in brainly.com/question/512038
#SPJ1
The electrons that are gained by the \(Ni^{2+}\) ion is 2.0 moles of electrons.
What is the number of the electrons gained?We know that when there is a redox reaction, there would be the loss or gain of electrons in the process. The process is a simultaneous one so the electrons that are lost by one specie must as a matter of necessity be gained by another specie.
In this case, as we look at the reaction equation we can see that there are two electrons that have been lost by the magnesium atom and these two electrons would be gained by the Nickel II ion.
Learn more about redox reaction:https://brainly.com/question/13293425
#SPJ1
What is the wavelength of a photon with a frequency of 6.56 x 10^14 Hz?
I will mark brainliest!!!!
Answer:457
Explanation:
If you have 2.86 gallons of pure water, how many molecules of water are ionized at any given time ?
Answer:
The molar mass of water is 18 grams per mole. So in 18 grams of water, there are 6.02 x 1023 molecules.
One gallon of water is equal to 3.7854118 liters. If we assume that the water is at 4 °C (to keep things simple), the density of water is exactly 1 gram per milliliter, or 1 kilogram per liter. So 1 gallon of water at 4 °C weighs exactly 3.7854118 kilograms, or 3785.41118 grams.
If one mole of water weighs 18 grams, then there are 210.30 moles of water in a gallon. Since one mole of water is made up of 6.02 x 1023 molecules, in one gallon of water there are 1.266 x 1026 molecules.
That is: 126600000000000000000000000 molecules!
If we multiply that by the number of atoms in a single water molecule -- 3 atoms -- then we get:
379800000000000000000000000 atoms!
The number of ionized water molecules at any given time in 2.86 gallons of pure water is approximately 2.08 x 10¹¹ molecules.
In pure water, only a small portion of water molecules are capable of self-ionization, which causes them to separate into hydronium ions (H3O+) and hydroxide ions (OH-). This procedure can be reversed.
The self-ionization of water can be represented as:
H₂O ⇌ H₃O+ + OH⁻
The concentration of each ion can be calculated using the equilibrium constant for water, Kw.
Kw = [H₃O⁺][OH⁻] = 1.0 x 10⁽⁻¹⁴⁾ at 25°C
Since the concentration of H³O⁺ ions is equal to the concentration of OH⁻ ions in pure water, let's assume that each concentration is x.
So, x² = 1.0 x 10⁽⁻¹⁴⁾
Taking the square root of both sides,
x = √(1.0 x 10⁽⁻¹⁴⁾)
≈ 1.0 x 10⁽⁻⁷⁾ M
The concentration of H₃O⁺ and OH⁻ ions in pure water is approximately 1.0 x 10^(-7) M.
To find the number of ionized water molecules,
= concentration x Avogadro's number x volume
= (1.0 x 10⁽⁻⁷⁾ M) x (6.022 x 10²³ molecules/mol) x (2.86 gallons) x (3.78541 liters/gallon)
≈ 2.08 x 10¹¹ molecules.
So, approximately 2.08 x 10¹¹ molecules of water are ionized.
To know more about Ionization, click here:
https://brainly.com/question/1602374
#SPJ2
1)Grignard reagent when reacted with methanol will yield A) ethanol (B) secondary alcohols (C) tertiary alcohols (D ropanol (E) primary alcohol
When the reaction of Grignard reagent reacted with methanol will yield a tertiary alcohol. Therefore, Option C tertiary alcohol is correct.
Contains a carbon-metal link, Grignard reagents are chemicals used in catalysis. They generally result from the anhydrous reaction of magnesium metal with an alkyl or aryl halide. Because of their high reactivity, Grignard reagents frequently act as nucleophiles in organic reactions.
An alkyl group from a Grignard reagent binds to the oxygen atom of methanol (CH3OH) when it interacts with the methanol, breaking the carbon-metal connection. A precursor alkoxide is created as a result. The equivalent alcohol is then produced by protonating the intermediate alkoxide.
The reaction of a Grignard reagent with methanol leads to the formation of a tertiary alcohol.
Learn more about reagents here:
https://brainly.com/question/29729676
the kenetic energy of a roller coaster is 100 joules. the potential energy of the same coaster is 100 joules. what is the mechanical energy of the coaster
What are the advantages of using moringa in water purification?
Nonsense = report
Best answer = brainliest
Answer:
moringa tree has seeds that have unique properties towards water purification
Explanation:
the seeds of moringa tree have an extract which can separate unwanted particulates from the water sediment impurities.
they have the
anti-microbial treatment potentials
moringa also has various vitamins since it is a plant tissue
# 16 of Approaching Equilibrium
For the reaction system A₂(g) + B₂(g) = 2AB(g)
the equilibrium constant K= 6.2
A system using this reaction was being tried in a 1.00 L reactor. It was charged with 0.20 mol A2, 0.15 mol B₂ and 0.60
mol AB.
The system was allowed to come to equilibrium. Which statement below describes the system coming to equilibrium?
(Note: in the answers, Q refers to the reaction quotient, K refers to the equilibrium constant).
Select one:
O a. The reaction goes to the right, more products will form because Q < K
O b. The reaction goes to the left, more reactants will form because Q > K
O c. The reaction goes to the right, more products will form because Q > K
O d.
It is not possible to predict in which direction the system will travel to arrive at equilibrium.
e.
The reaction goes to the left, more reactants will form because Q < K
From the calculation, Q >K, the reaction proceeds towards the left and more reactants will form.
What is equilibrium constant?The term equilibrium constant refers to the value that could indicate the extent of conversion of reactants to products.
Thus, given that the equilibrium constant for the reaction A₂(g) + B₂(g) = 2AB(g) is 6.2, the Qc is obtained from;
Qc = [0.60]^2/[0.20] [0.15]
Qc = 0.36/0.03
Qc = 12
Since Q >K, the reaction proceeds towards the left and more reactants will form.
Learn more about equilibrium constant:https://brainly.com/question/10038290
#SPJ1
accelerating hydrogen absorption and desorption rates in palladium nanocubes with an ultrathin surface modification
An incredibly intriguing Palladium approach to high-rate energy storage and distribution is to take advantage of the high surface-area-to-volume ratio of nanomaterials by storing energy in the form of electrochemical alloys.
Palladium hydride at the nanoscale is a great model system for learning how characteristics at the nanoscale influence the absorption and desorption of energy-carrying equivalents. In shape-controlled Pd nanostructures, hydrogen absorption and desorption do not take place uniformly throughout the surface of the nanoparticles. Instead, high-activity spots at the corners and edges are used to selectively absorb and desorb hydrogen. With such a process, the benefits of shrinking the palladium's size to the nanoscale are significantly diminished. We alter the palladium surface with an incredibly thin platinum shell to resolve this. This alteration allows diffusion to occur across the entire Pd/Pt surface and practically eliminates the barrier to hydrogen absorption (89 kJ/mol without a Pt shell and 1.8 kJ/mol with a Pt shell).
To learn more about Palladium please click on below link
https://brainly.com/question/28597992
#SPJ4
Here is a second order reaction A→ P. If the initial concentration of A 0.0818 M goes down 30.0% in 3.15 minutes, what is the rate constant for the reaction?
The rate constant of the second-order reaction is 0.111 M^-1 min^-1.
The given data represents a second-order reaction where the rate of the reaction is proportional to the square of the concentration of A.
The integrated form of the second-order reaction is:
1/[A]t = kt + 1/[A]0
where [A]t and [A]0 are the concentrations of reactant A at time t and time zero, respectively, k is the rate constant.
We can use the given information to calculate the rate constant (k) of the reaction for the given half-life (t1/2) of 3.15 minutes:
t1/2 = (1 / k[A]0)
Using the percentage decrease in concentration and the given initial concentration, we can calculate the concentration of A at time t:
[A]t = [A]0 - 0.30[A]0 = 0.57126 M
Substituting the given values, we get:
3.15 min = (1 / k)(0.0818 M) / (0.0818 M - 0.57126 M)
Simplifying the equation above, we can solve for k:
k = 0.111 M^-1 min^-1
Therefore, the rate constant of the second-order reaction is 0.111 M^-1 min^-1.
For such more questions on constant
https://brainly.com/question/3159758
#SPJ11
1. Several solids, liquids, and gases can be found in your home. List three examples of each. (9 points) Think about where solids, liquids, and gases might be found in your refrigerator, bathroom, or basement/garage.
2. What states of matter exist within the human body? What state of matter do you think your body is mostly made up of? Why? (4 points) Think about whether the body contains solids, liquids, or gases. Which of the three would you be most likely to find?
3. Your blood contains many dissolved solids. What do you think could be done if you needed to remove the water from a sample of blood in order to study the solids that remained? (4 points) Think about what processes remove water from watery foods, solutions, or objects.
4. Your body contains a considerable amount of dissolved metal ions. Based on what you know about food and nutrition, list at least three metals you think could be found within the human body. (3 points) Refer to the periodic table — do any of the metal element names seem familiar? (Think about the ingredients list printed on food labels.)
1. Examples of solids, liquids, and gases found in a home
Solids: books, furniture, toys
Liquids: water, juice, shampoo
Gases: air, natural gas, propane
2. The human body contains solids, liquids, and gases. Solids include bones, muscles, and organs. Liquids include blood, saliva, and urine. Gases include air in the lungs and dissolved gases in the bloodstream. The body is mostly made up of liquids, as they make up a large percentage of its overall volume.
3. If you needed to remove the water from a sample of blood to study the solids that remained, you could use a process such as evaporation or freeze-drying. Evaporation involves heating the sample to allow the water to evaporate, leaving behind the solids. Freeze-drying involves freezing the sample and then removing the water under vacuum, leaving behind a dry solid.
4. Some metals that could be found within the human body include iron, zinc, and copper. These metals are commonly found in foods such as meat, seafood, nuts, and whole grains. Other metals such as calcium, magnesium, and potassium are also important for the body and are found in a variety of foods.
To know more about solids here
https://brainly.com/question/21500863
#SPJ1
Using this equation, m1v2=m2v2 , calculate the diluted molarity of 100 mL of a 0.5 M solution when 50 mL of
water has been added.
The molarity of the diluted solution is 0.33 M
From the question given above, the following data were obtained:
Molarity of stock solution (M₁) = 0. 5 M
Volume of stock solution (V₁) = 100 mL
Volume of diluted solution (V₂) = 100 + 50 = 150 mL
Molarity of diluted solution (M₂) =?The molarity of the diluted solution can be obtained by using the dilution formula as illustrated below:
M₁V₁ = M₂V₂0.5 × 100 = M₂ × 150
50 = M₂ × 150
Divide both side by 150
M₂ = 50 / 150
M₂ = 0.33 MTherefore, the molarity of the diluted solution is 0.33 M
Learn more: https://brainly.com/question/24625656
K₂SO₄(aq) + SrI₂(aq) → 2KI(aq)+ SrSO₄(s) net ionic equation
Answer:
SO4 (aq) + Sr (aq) >> SrSO4 (s)
Explanation:
K+1 SO4-2 + Sr +2 I2- >> sK +1
(you dont separate and write down the ions for Sr SO4 because its a solid)
Cancel out the same ions from both sides and write down what your left with.
What is the BIG Difference between Charles' Law and Guy-Lussac's Law
Can someone please help me please?
Answer:8.04 grams
Explanation:
By the ratio we get 0.45 moles of H20
Then by simply multiplying with Mr gives the result
What happened when Crookes placed a solid object inside
the cathode ray tube?
a
The object cast a shadow on the other end of the
tube.
b The object exploded.
С
The cathode rays burned a small hole in the
object.
d The cathode ray tube stopped working.
Which chapter is bulk properties of matter?
The list which includes only bulk properties of matter is boiling point, surface tension and vapor pressure.
Definition of matter
Something that has mass and occupies space is defined as a matter.
Hence, all the physical objects or substances that are found on the planet Earth are typically composed of matter.
Matter are classified into three (3) states:
Gas
Solid
Liquid
The property of the matter that affects matter as a whole is known as bulk property of matter and they are listed as follows:
Boiling pointElasticityStrainStressSurface tensionVapor pressureHence, boiling point, vapor pressure and surface tension are considered as a bulk properties of matter.
Learn more about bulk properties of matter from the link given below.
https://brainly.com/question/29546212
#SPJ4
1 point
Why DOESN'T the equation pictured satisfy the Law of Conservation of
Matter?
H202 → H20 + O2
The subscript of oxygen is different on the reactant side compared to product side.
The products are different than the reactants.
There are more oxygen atoms after the reaction than there were before the reaction.
The total mass of reactants is different than the total mass of products.
Explanation:
The equation doesn't satisfy the Law of Conservation of Matter because There are more oxygen atoms after the reaction than there were before the reaction.
Therefore,
Option C is correct ✔
what kind of heat treatment cause toxic fumes to form
Jonathon is conducting an experiment to determine how much precipitate (solid product) will form when combining measured volumes of Aich, and NaOH. According to his calculations the reaction should produce 26.0 grams of solid AKOH), when combined. However, when Jonathon measures the mass of the solid precipitate formed in his experiment, he finds that the experiment actually produced 24.5 grams of Al(OH).
Jonathon's experiment produced 24.5 grams of Al(OH), which is less than the predicted amount of 26.0 grams of AKOH. The discrepancy could be due to measurement errors, incomplete reaction.
What is discrepancy?
To determine the cause of the discrepancy, Jonathon should first review his experimental procedure and make sure that all measurements and calculations were performed accurately. He should also check that the reactants were mixed thoroughly and that the reaction was allowed to proceed to completion. If any errors or inconsistencies are identified, Jonathon should correct them and repeat the experiment to obtain more accurate results.
If the experimental procedure was carried out correctly and the discrepancy cannot be attributed to measurement errors, Jonathon should consider the possibility of impurities in the reactants. Even small amounts of impurities can affect the outcome of a chemical reaction, so it is important to use high-quality, pure chemicals in experiments whenever possible.
Overall, the most important thing for Jonathon to do in this situation is to carefully review his experimental data and methodology, and to identify any potential sources of error or uncertainty. By doing so, he can improve the accuracy and reliability of his results and draw more meaningful conclusions from his experiment.
To know more about reactants, visit:
https://brainly.com/question/13005466
#SPJ9
Write the objectives for the topic "Synthetic Fibre & Plastics"
Answer:
1. To understand the differences between natural and synthetic fibers and their properties.
2. To learn about the manufacturing process of synthetic fibers and plastics and the different types of synthetic fibers and plastics available.
3. To explore the various applications of synthetic fibers and plastics in different industries such as fashion, automotive, construction, and electronics.
4. To investigate the environmental impact of synthetic fibers and plastics and the importance of recycling and proper disposal methods.
5. To evaluate the advantages and disadvantages of synthetic fibers and plastics compared to natural materials and their impact on society and the economy.
6. To analyze the future trends and innovations in the field of synthetic fibers and plastics and their potential impact on different industries and the environment.
Calculate ΔHrxn for the following reaction: 5C(s) 6H2(g)→C5H12(l) Use the following reactions and given ΔH values: C5H12(l) 8O2(g)→5CO2(g) 6H2O(g),ΔHC(s) O2(g)→CO2(g),ΔH2H2(g) O2(g)→2H2O(g),ΔH
Answer: its 4xb236.52
Explanation:
The symbol for xenon (Xe) would be a part of the noble gas notation for the element
This is getting annoying
Chemical element xenon (Xe), which belongs to the periodic table's Group 18 (noble gases), is a hefty and incredibly uncommon gas.
What are noble gas ?Any of the rare gases that display high stability and very low reaction rates, such as helium, neon, argon, krypton, xenon, and typically radon. — Also known as inert gas.
Thus, Chemical element xenon (Xe), which belongs to the periodic table's Group 18 (noble gases), is a hefty and incredibly uncommon gas.
To learn more about noble gas, refer to the below link:
https://brainly.com/question/13933772
# SPJ1
Basic Stoichiometry:1. Magnesium oxide reacts with phosphoric acid to produce magnesium phosphate and water. How many grams of phosphoric acid are required to completely react with 2357g of magnesium oxide?3MgO + 2H3PO4 --> Mg3(PO4)2 + 3H2O
Step 1 - Understanding the reaction and finding its stoichiometry
The reaction between Magnesium oxide and Phosporic acid is as follows:
\(3\text{MgO}_{(s)}+2H_3PO_{4(aq)}\to Mg_3(PO_4)_{2(aq)}+3H_2O_{(l)}\)We can see that 3 moles of MgO react with 2 moles of H3PO4. We can convert this relation in moles to a relation in mass by multiplying each number of moles by the respective molar mass of the substance (40 g/mol for MgO; 98 g/mol for H3PO4):
\(\begin{gathered} \text{MgO}\to\text{ 3}\times40=120\text{ g} \\ H_3PO_4\to2\times98=196\text{ g} \end{gathered}\)We know, therefore, that 120 g of MgO react with 196 g of H3PO4. This is like a cake recipe: it is a fixed proportion. It is like you knew how many eggs and sugar you would need so they can make a cake and nothing is left.
Step 2 - Using the stoichiometry of the reaction to solve the exercise
Now that we already know the recipe, we can use it to predict how much we will to make more or less cake. Remember: the proportion between the reactants is always a fixed one.
Since we want to know how many grams of H3PO4 are necessary to completely react with 2357 g of MgO, we can set the following proportion:
\(\begin{gathered} 120\text{ g of MgO react with ---- 196 g of H3PO4} \\ 2357\text{ g of MgO react with ---- x} \\ \\ x=\frac{2357\times196}{120}=3849.7\text{ g } \end{gathered}\)We would need, therefore, 3849.7 g of MgO to completely react with the given mass of H3PO4.
note: To calculate the molar mass of a substance, we just have to sum up the molar masses of the atoms, multiplying each molar mass by the number of times each atom appears in the formula. The molar mass of the atoms can be found in the periodic table.
Let's use H3PO4 as an example. Looking at a periodic table, we find the molar masses:
\(\begin{gathered} H\to\text{ 1 g/mol} \\ O\to16\text{ g/mol} \\ P\to31\text{ g/mol} \end{gathered}\)The molar mass of H3PO4 would be thus:
\(M(H_3PO_4)=3\times1+4\times16+31=3+64+31=98\text{ g/mol}\)