NH3(aq)+HCl(aq)=NH4CI(aq) (ammonium chloride)
0.157 mol NH3 >> 6.91 kJ of energy
1 moles of NH3 >>>6.91 kJ/0.157
Delta H for this reaction per mole of NH3 consumed will therefore be :
ΔH =6.91 kJ/0.157
= 44.019kJ
∴ΔH per mole ≈44.02 kJ
Which product is formed by positron emission from P-32?
Answer:
Beta emission measn -1e0
Here reactant is phosphorus-32.
phosphorus-32 --- > product + -1e^0
product = 16 S^32
P-32 beta decays to S-32. On the beta emission the product is formed which has same number of mass but the atomic number more than 1 of the reactant.
What color is this? I think it’s blue or gray, but I’m color blind.
Answer:
BLACK
Explanation:
the color is black
Answer: 1st one is black second one is also black
Explanation:
Exactly 0.2220 g of pure Na2CO3 was dissolved in 100.0 mL of 0.0731 M HCl. (a) What mass in grams of CO2 was evolved
This problem is providing information about a chemical reaction between sodium carbonate and hydrochloric acid. Thus, the mass of evolved carbon dioxide is required and found to be 0.0922 g according to:
Stoichiometry:
In chemistry, stoichiometry is a tool that allows us to perform mole-mass calculations based on proportional factors involving the balanced chemical equation, molar masses and mole ratios. In such a way, for the reaction in this problem, we write:
\(2HCl+Na_2CO_3\rightarrow 2NaCl+H_2O+CO_2\)
In such a way, since both HCl and Na2CO3 are given, we calculate the grams of CO2 produced by each one, to identify the limiting reactant, according to the 2:1 and 1:1 mole ratios the reactants have with CO2 respectively:
\(0.2220gNa_2CO_3*\frac{1molNa_2CO_3}{106gNa_2CO_3} *\frac{1molCO_2}{1molNa_2CO_3}*\frac{44.01 gCO_2}{1molCO_2}= 0.0922gCO_2\\ \\ 0.1000L*0.0731\frac{molHCl}{L} *\frac{1molCO_2}{2molHCl}*\frac{44.01 gCO_2}{1molCO_2}=0.161gCO_2\)
Thus, since Na2CO3 produce the smallest amount of CO2, we infer it is the limiting reactant and therefore the correct produced amount is 0.0922 g.
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Q2.Which is true about potassium?
Extremely unreactive
Not very reactive
Slightly reactive
Very reactive
A scientist studies weather patterns to learn where and how fast the wind blows in different situations. How might this scientific knowledge be used to solve a practical problem?
It could help to decide where to put windmills to capture wind energy.
It could help to predict when dangerous storms are coming so people can prepare.
It could help in designing buildings so that they are not damaged by wind.
All of the above.
Scientific knowledge be used to solve a practical problem through all of the above which are:
It could help to decide where to put windmills to capture wind energy.It could help to predict when dangerous storms are coming so people can prepare.It could help in designing buildings so that they are not damaged by wind.What is Wind?This is defined as the movement of air and other gases on the surface on the earth. Wind intensity varies according to various factors and it's best to study it as helps to prepare for unforeseen circumstances.
Its knowledge helps in the building of windmills so as to ensure efficient capture of winds.
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Which of the following statements is true?
Incandescent light bulbs are almost 100 percent efficient.
Endothermic reactions release heat.
Heat is considered "lost" energy because it cannot be used for work.
An electric drill gains energy in the form of heat and sound.
Answer:
D
Explanation:
Answer:
I know i'm late but here the answer Heat is considered "lost" energy because it cannot be used for work.
Explanation:
Why do all elements have their own unique color? Please explain.
All the element have their own unique color because the every element have their own set of energy levels.
According to the bohr model of atoms : electrons exist at certain energy levels. when we give heat to electron , it gets excited and moves from lower energy level to higher energy level. the electron is less stable in higher energy level. when an electron returns from higher energy level to lower energy level it emits some energy in form of radiation. The wavelength of light depends upon energy level . and every elements have their own unique energy levels. The color for different element is different.
Thus, All the element have their own unique color because the every element have their own set of energy levels.
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amobarbital sodium react with ethanolic sodium hyrooxide
Amobarbital (like all barbiturates) works by being incontestible to the GABAA receptor at either the alpha or the beta subunit.
What is the mechanism of amobarbital?Amobarbital (like all barbiturates) works by binding to the GABAA receptor at either the alpha or the beta subunit. These are compulsory sites that are distinct from GABA itself and also distinct from the benzodiazepine binding site.
Amobarbital is a barbiturate classified as having a halfway duration of action, meaning that the effects of the drug can last from 4-6 amobarbital increases the effects of benazepril by apparatus: pharmacodynamic synergism.
So we can conclude that Amobarbital, 5-ethyl-5-isoamyl barbituric acid like all barbiturates.
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2.
Which mixture could be a useful buffer in a solution?
acetic acid (CH3CO2H) and hydrochloric acid (HCl)
sodium hydroxide (NaOH) and elemental sodium (Na)
ammonia (NH3) and ammonium chloride (NH4Cl)
acetic acid (CH3CO2H) and ammonia (NH3)
Pls answer quickly
Ammonia (\(NH_3\)) and ammonium chloride (\(NH_4Cl\)) mixture could be a useful buffer in a solution. Option C
A buffer is a solution that can resist changes in pH when small amounts of acid or base are added. It consists of a weak acid and its conjugate base or a weak base and its conjugate acid. The buffer system works by the principle of Le Chatelier's principle, where the equilibrium is shifted to counteract the changes caused by the addition of an acid or a base.
In option A, acetic acid (\(CH_3CO_2H\)) is a weak acid, but hydrochloric acid (HCl) is a strong acid. This combination does not form a buffer because HCl is completely dissociated in water and cannot provide a significant concentration of its conjugate base.
Option B consists of sodium hydroxide (NaOH), which is a strong base, and elemental sodium (Na), which is a metal. This combination does not form a buffer as there is no weak acid-base pair involved.
Option D contains acetic acid (\(CH_3CO_2H\)), a weak acid, and ammonia (\(NH_3\)), a weak base. Although they are weak acid and base, they do not form a buffer system together as they are both weak acids or bases and lack the required conjugate acid-base pair.
Option C, ammonia (\(NH_3\)), is a weak base, and ammonium chloride (\(NH_4Cl\)) is its conjugate acid. This combination can form a buffer system. When ammonia reacts with water, it forms ammonium ions (NH4+) and hydroxide ions (OH-).
The ammonium ions act as the weak acid, while the ammonia acts as the weak base. The addition of a small amount of acid will be counteracted by the ammonium ions, and the addition of a small amount of base will be counteracted by the ammonia, thus maintaining the pH of the solution relatively stable.
Therefore, option C, consisting of ammonia (\(NH_3\)) and ammonium chloride (\(NH_4Cl\)), is the suitable mixture that could be a useful buffer in a solution.
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According to “Past Climate Changes on Earth,” what changes to the atmosphere caused temperatures to increase, making the Eocene such a warm time in Earth’s history? ____________________________________________________________________________
The changes to the atmosphere that caused temperatures to increase, making the Eocene such a warm time in Earth’s history was the increase in concentrations of greenhouse gases, primarily carbon dioxide (CO2) and methane (CH4).
What was the Eocene period?The Eocene period was a geological epoch that lasted from approximately 56 to 34 million years ago, occurring between the Paleocene and Oligocene epochs.
During this epoch, the Earth experienced a greenhouse climate, with higher global temperatures and high levels of carbon dioxide in the atmosphere.
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How many moles are in 8.7 x 104 atoms of oxygen?
5. Which of the functional groups contain(s) nitrogen?
Explanation:
Functional groups containing nitrogen are amines and amides.
The general formula for amines is:
RNH₂, where R = longer hydrocarbon chain.
The general formula for amides is:
RCONH₂, where R = longer hydrocarbon chain.
See attached diagram for general structural formula.
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What is the reaction of Dimethylamamine + acetic acid
You are making a fluorescence measurement at a concentration of 500 pM and get a signal to noise of 5. If you need a detection limit of 75 pM, by how much do you need to increase the source power? Assume all you noise is from the instrument so you can use the 3 x standard deviation definition.
By -320 pM, we need to increase the source power. A fluorescent material begins to produce visible light when energy is absorbed as a result of the incidence of X-rays, light waves, and electrons.
What is fluorescence?When a substance generates electromagnetic waves inside the longer wavelength range and makes them visible to the human eye, it is a fascinating occurrence. Let's first define fluorescence in order to comprehend this. This allows the substance to gently transition from the partly excited state to the ground state. Fluorescence is the term for this phenomena.
Detection limit = 3 × noise / signal to noise ratio
Detection limit = 3× 75 pM / 5 = 15 pM
Source power = (noise / desired detection limit)² × current source power
Source power = (15 pM / 75 pM)² ×500 pM
= 0.36 ×500 pM
= 180 pM
Source power= 180 pM - 500 pM =
=-320 pM
Therefore, -320 pM, we need to increase the source power.
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In the Brønsted–Lowry definition of acids and bases, a base __________
Answer: is a substance that accepts hydrogen ions.
what are the cations and anions of NiS
The correct answer is cation Ni +2 and anion S 2-.
Nickel sulfide
It is discovered that the bonding in NiS is remarkably similar to that in NiO, with a covalent component resulting from bonds between the Ni 3d and the S 3p atom and an ionic contribution resulting from the donation of the Ni 4s electron to the S atom.
With heated concentrated nitric acid or aqua regia, NiS can be easily reactively dissolved, which is followed by sulphur precipitation.
F belongs to Group 7A, while Ni is in Group 5A. (EN: N=3.0, F=4.0) The NF3 molecule and each N-F bond are both polar. F possesses a partial positive charge in the N-F bond. The NF3 molecule and each N-F bond are both non-polar.
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fill in the blank. complete the energy maximum electron capacity for each energy level. energy level 1 maximum electron capacity is choose___ . energy level 2 maximum electron capacity is choose___. energy level 3 maximum electron capacity is choose___. energy level 4 maximum electron capacity is choose___.
The maximum electron capacity at energy level 1 is 2. The maximum electron capacity at energy level 2 is 8. Maximum electron capacity at energy level 3 is 18. The maximum number of electrons at energy level 4 is 32.
What is electron?Having a negative electric charge, an electron is a subatomic particle. Together with protons and neutrons, it is one of the basic building blocks of atoms.
The chemical characteristics of elements are determined by electrons, which are found in the valence shell, the outermost shell of an atom. In addition, they have a role in the production of magnetism, electrical conduction, and chemical processes. Additionally, as in an electron beam, electrons can also exist freely and independently.
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Do you think it's possible for someone to completely eliminate procrastination from their life? Why or why not
Answer:
No and Yes
Explanation:
This is both possible and impossible. When you put your mind to what you believe, you can achieve it through patience and minded values. Your mind can either be your Greatest enemy or your Best Ally.
For the reaction C + 2H2 - CH4
how many grams of carbon are required to produce 10.7 moles of methane, CH4?
Use the following molar masses:
hydrogen: 1
carbon: 12
Taking into account the reaction stoichiometry, 128.4 grams of C are required to produce 10.7 moles of methane.
Reaction stoichiometryIn first place, the balanced reaction is:
C + 2 H₂ → CH₄
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
C: 1 moleH₂: 2 molesCH₄: 1 moleThe molar mass of the compounds is:
C: 12 g/moleH₂: 2 g/moleCH₄: 16 g/moleThen, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
C: 1 mole ×12 g/mole= 12 gramsH₂: 2 moles ×2 g/mole= 4 gramsCH₄: 1 mole ×16 g/mole= 16 gramsMass of C requiredThe following rule of three can be applied: If by reaction stoichiometry 1 mole of CH₄ is produced by 12 grams of C, 10.7 moles of CH₄ are produced by how much mass of C?
mass of C= (10.7 moles of CH₄×12 grams of C)÷1 mole of CH₄
mass of C= 128.4 grams
Finally, 128.4 grams of C are required.
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The smallest arteries in your body are called _____. arterioles capillaries veins bronchioles
Answer: arterioles
Explanation:
Two samples of carbon come into contact. A heat transfer will occur between sample A and sample B. What must be true
for heat to transfer from sample A to sample B?
The average kinetic energy of A is greater than that of B.
The average kinetic energy of B is greater than that of A.
The average kinetic energy of both samples is equal.
The average kinetic energy does not determine the direction of heat transfer.
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Calculate the number of moles of sulfuric acid in the total volume you used in the lab (i.e., 8.00 mL). Hint: Use the methodology of Question (1) above for finding out the molarity of the concentrated sulfuric acid first from its density (1.84 g/mL) and concentration (98.0% w/w), then find the number of moles. Show full work.
Answer:
0.147 mol
Explanation:
Step 1: Calculate the volumetric concentration (Cv)
We will use the following expression.
Cv = Cg × ρ
Cv = 98.0 g%g × 1.84 g/mL = 180 g%mL
Step 2: Calculate the molarity of sulfuric acid
We will use the following expression.
M = mass solute / molar mass solute × liters of solution
M = 180 g / 98.08 g/mol × 0.100 L = 18.4 M
Step 3: Calculate the moles of solute in 8.00 mL of solution
8.00 × 10⁻³ L × 18.4 mol/L = 0.147 mol
A 30-kg iron block and a 40-kg copper block, both initially at 80∘C, are dropped into a large lake at 15∘C. Thermal equilibrium is established after a while as a result of heat transfer between the block and the lake water. Determine the total entropy change for this process.
A 30-kg iron block and a 40-kg copper block, both initially at 80∘C, are dropped into a large lake at 15 °C. The total entropy change for this process is 0.64kJ/ K.
given that :
mass of iron block , mFe = 30 kg
mass of copper block mCu = 40 kg
temperature T1 = 80 °C = 353 K
temperature T2 = 15 °C = 288 K
the entropy change for iron block is given as :
ΔS fe = mc ln(T2/T1)
ΔS fe = 30 × 0.45 × ln ( 288/ 353)
ΔS fe = - 2.74 kJ/ K
The entropy change for copper :
ΔS Cu = 40 × 0.386 ln ( T2 / T1)
ΔS Cu = - 3.14 kJ/ K
the heat transfer to the lake :
Q out = - mFe cFe ( T2 - T1 ) - mCu cCu ( T2 - T1 )
= - 30 × 0.45 ( 15 - 80 ) - 40 × 0.386 ( 15 - 80 )
= 1881.1 kJ
the entropy change for the lake :
ΔS lake = Q out / T2
= 1881.1 / 288
= 6.53 kJ/K
the total entropy change is given as follows :
ΔS = - 2.747 - 3.142 + 6.53
= 0.64 kJ/ K
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An unknown hydrocarbon compound was analyzed for hydrogen by elemental analysis and results show that it contains 15.88 % H. What is the empirical formula? C4H9 C8H18 C12H27
Answer:
If H = 15.88%
Then C = 100.00 – 15.88 = 84.12%
Divide each % value by respective atomic mass
H = 15.88/1 = 15.88
C = 84.12/12 = 7.01
Divide through by smaller value
H = 15.88/7.01 = 2.26
C = 7.01/7.01 = 1
Remove fraction , multiply by 4
H = 9
C = 4
Empirical formula = C4H9
The hydrocarbon could be ( C4H9)2 = C8H18 = octane.
1. On the basis of the Keq values given in the table, which reaction mixture contains the largest amount of product(s)
when at equilibrium? Explain.
2. Which reaction mixture contains the largest amount of reactants when at equilibrium?
3. Which reactions in the table have concentrations that represent the systems at equilibrium?
4. For each reaction that is not at equilibrium, change the concentration of only one of the reactants or
products so that the ratio represents the system at equilibrium
1. The reaction mixture with the largest amount of product(s) when at equilibrium is the one with the largest Keq value.
2. The reaction mixture with the largest amount of reactants when at equilibrium is the one with the smallest Keq value
3. The reactions in the table that have concentrations that represent the systems at equilibrium are Reactions 1 and 3.
4. For each reaction that is not at equilibrium, change the concentration of only one of the reactants or products so that the ratio represents the system at equilibrium.
How to explain the information1. In this case, the reaction mixture with the largest Keq value is Reaction 2. This is because the equilibrium constant, Keq, is a measure of the relative concentrations of the products and reactants at equilibrium. A large Keq value indicates that the equilibrium lies far to the right, meaning that there are more products than reactants at equilibrium.
2. The reaction mixture with the largest amount of reactants when at equilibrium is the one with the smallest Keq value. In this case, the reaction mixture with the smallest Keq value is Reaction 4. This is because a small Keq value indicates that the equilibrium lies far to the left, meaning that there are more reactants than products at equilibrium.
3. The reactions in the table that have concentrations that represent the systems at equilibrium are Reactions 1 and 3. This is because the concentrations of the products and reactants in these reactions are equal, which is the definition of equilibrium.
4. For each reaction that is not at equilibrium, change the concentration of only one of the reactants or products so that the ratio represents the system at equilibrium. For example, to bring Reaction 2 to equilibrium, we could increase the concentration of H2O or decrease the concentration of CO2.
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Reaction Keq Concentrations at Equilibrium
1 1000 H2O:CO2 = 1:1
2 10 H2O:CO2 = 10:1
3 0.01 H2O:CO2 = 100:1
4 0.001 H2O:CO2 = 1000:1
On the basis of the Keq values given in the table, which reaction mixture contains the largest amount of product(s) when at equilibrium? Explain.
2. Which reaction mixture contains the largest amount of reactants when at equilibrium?
3. Which reactions in the table have concentrations that represent the systems at equilibrium?
4. For each reaction that is not at equilibrium, change the concentration of only one of the reactants or
products so that the ratio represents the system at equilibrium
What 2 locations have the greatest kinetic energy
Answer:
what??? Is this the complete quetion??
When metallic sodium is dissolved in liquid sodium chloride, electrons are released into the liquid. These dissolved electrons absorb light with a wavelength near 800. nm. Suppose we treat the positive ions surrounding an electron crudely as defining a three-dimensional cubic box of edge , and we assume that the absorbed light excites the electron from its ground state to the first excited state. Calculate the edge length in this simple model.
Answer:
The edge of the length is \(\mathbf{L = 8.54 \times 10^{-10} \ m}\)
Explanation:
From the given information:
The associated energy for a particle in three - dimensional box can be expressed as:
\(E_n = \dfrac{h^2}{8mL^2}(n_x^2+n_y^2+n_z^2)\)
here;
h = planck's constant = \(6.626 \times 10^{-34} \ Js\)
\(n_i\) = the quantum no in a specified direction
m = mass (of particle)
L = length of the box
At the ground state \(n_x = n_y = n_z=1\)
The energy at the ground state can be calculated by using the formula:
\(E_1 =\dfrac{3h^2}{8mL^2}\)
At first excited energy level, one of the quantum values will be 2 and the others will be 1.
Thus, the first excited energy will be: 2,1,1
∴
\(E_2 =\dfrac{(2^2+1^2+1^2)h^2}{8mL^2}\)
\(E_2 =\dfrac{(4+1+1)h^2}{8mL^2}\)
\(E_2 =\dfrac{(6)h^2}{8mL^2}\)
The transition energy needed to move from the ground to the excited state is:
\(\Delta E= E_2 - E_1\)
\(\Delta E= \dfrac{6h^2}{8mL^2}- \dfrac{3h^2}{8mL^2}\)
\(\Delta E= \dfrac{3h^2}{8mL^2}}\) ----- (1)
Recall that:
the wavelength identified with the electronic transition is: 800 nm
800 nm = 8.0 × 10⁻⁷ m
However, the energy-related with the electronic transition is:
\(\Delta E =\dfrac{hc}{\lambda}\)
\(\Delta E =\dfrac{6.626 \times 10^{-34} \times 2.99 \times 10^8}{8.0 \times 10^{-7} }\)
\(\Delta E =2.48 \times 10^{-19} \ J\)
Replacing the value of \(\Delta E\) in (1); then:
\(2.48 \times 10^{-19}= \dfrac{3h^2}{8mL^2}}\)
Making the edge length L the subject of the formula; we have:
\(L = \sqrt{\dfrac{3h^2}{8m \times2.48 \times 10^{-19}} }\)
\(L = \sqrt{\dfrac{3\times (6.626 \times 10^{-34})^2}{8(9.1 \times 10^{-31} ) \times2.48 \times 10^{-19}} }\)
\(\mathbf{L = 8.54 \times 10^{-10} \ m}\)
Thus, the edge of the length is \(\mathbf{L = 8.54 \times 10^{-10} \ m}\)
5. What physical property of foam makes it a good choice to
use in life vests?
A. Foam has a relative density less than water.
B. Foam is a good thermal insulator.
C Foam is non-magnetic.
D. Foam is soluble in water.
The burning of fossil fuels, like coal, oil, and natural gas, DO NOT contribute to the presence of greenhouse gases in the atmosphere.
True
or
False
Answer:
false statements because they are all nonrenewable resources
A pure substance that is present before a reaction but not after
Super Confused
Explanation:
Pure subsance is a substance that is made up of only one type of particle - each piece is the same throughout.
Being present before the reaction but not after means it's no the same (it couldve evaporated)