Explanation:
Given that,
Manganese-56 decays by beta emission and has a half-life of 2.6 hours.
We need to find no of half lives in 24 hours. It can be calculated by dividing 24 hours by 2.6 hours. So,
\(T=\dfrac{24}{2.6}=9.23\ \text{half lives}\)
Let x mg of a2 0 mg sample remain after 5 half-lives.
\(x=20\ mg\times \dfrac{1}{2^5}\\\\x=0.625\ \text{mg}\)
Hence, there are 9.23 half lives and 0.625 mg of sample will remain after 5 half lives.
what are valence electrons? why are they so important in chemistry?
Answer:
Valence electrons are negatively charged particles located in the outermost shell of atoms that can be transferred or shared with other atoms. Valence electrons are important in chemistry because the number of valence electrons in a particular atom can be used to determine how the atom will react chemically with other atoms.
. the accompanying graph shows the concentration of a reactant as a function of time for two different reactions. one of the reactions is first order and the other is second order. which of the two reactions is first order? second order? how would you change each plot to make it linear?
Based on the graph, the reaction with a linear decrease in concentration is the first-order reaction, while the reaction with a curved decrease is the second-order reaction.
In a first-order reaction, the concentration of the reactant decreases exponentially with time, resulting in a straight line on a graph of ln(concentration) versus time. Therefore, to make the plot of the first-order reaction linear, we need to plot ln(concentration) on the y-axis.
In a second-order reaction, the concentration of the reactant decreases at a rate proportional to the square of its concentration, resulting in a curved line on a graph of concentration versus time. To make the plot of the second-order reaction linear, we need to plot 1/concentration on the y-axis.
By transforming the y-axis to ln(concentration) for the first-order reaction and 1/concentration for the second-order reaction, we can observe linear relationships between the transformed y-axis and time for both reactions.
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pls solve this question
b) Briefly explain why Waste Electrical \& Electronic Equipment (WEEE) regulations are important? (3 marks)
Answer: they are important for one, they cant be combined
Explanation: i cant really explain
you mix 250 mL of 2.1 M HBr with 200 mL of 2.5 M KOH. what is the pH of the resulting solution?⢠12.7⢠1.6⢠12.4⢠1.3
When we mix 250 mL of 2.1 M HBr with 200 mL of 2.5 M KOH. The pH of the resulting solution is 12.7 .
The volume of the HBr = 250 mL
The molarity of the HBr = 2.1 M
The moles = molarity × volume
= 0.250 × 2.1
= 0.52 mol
The volume of the KOH = 200 mL
The molarity of the KOH = 2.5 M
The moles = molarity × volume
= 2.5 × 0.200
= 0.5 mol
The KOH is excess, the excess amount is = 0.525 - 0.5
= 0.025 mol
The equation is as :
HBr + KOH ----> KBr + H₂O
The total volume = 0.250 + 0.200
= 0.45 L
The concentration of [OH⁻] = 0.025 / 0.45
= 5 × 10⁻² M
pOH = - log ( 5 × 10⁻² )
pOH = 1.3
pH = 14 - pOH
pH = 14 - 1.3
pH = 12.7
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A person runs 10 laps around 400m track in 20 min.calculate the runners average velocity in m/s
Explanation:
400×10=4000m
20×60=1200s
S=D÷T
S=4000÷1200
S=3.33m/s
A solution contains 7.8% W/V ethanol. Express this in units of g/mL.
A solution that contains 7.8% W/V ethanol is equivalent to 0.078g/mL. Details about weights per volume can be found below.
How to convert W/V% to g/mL?Weights per volume is a unit for measuring density of a substance. It can be converted to g/mL using the following expression:
w/v% = g/100mL
According to this question, a solution contains 7.8% W/V ethanol. The equivalent of this in g/mL is as follows:
7.8% W/V = 7.8g/100mL
= 0.078g/mL
Therefore, a solution that contains 7.8% W/V ethanol is equivalent to 0.078g/mL.
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4. What holds a moon in its orbit? *
The density of a liquid is determined by successively weighing 25, 50, 75, 100, and 125 mL of the liquid in a 250-ml beaker. If volume of liquid is plotted along the horizontal axis, and total mass of beaker plus liquid is plotted on the vertical axis: Select one:
a. The x, or horizontal, intercept is the negative value of the weight of the beaker.
b. The slope of the line is independent of the identity of the liquid.
c. The y, or vertical, intercept is the weight of the empty beaker,
d. The line will pass through the origin.
e. The slope of the line is 1.0.
C. The y, or vertical, intercept is the weight of the empty beaker.
When determining the density of a liquid, it is important to use a specific container to hold the liquid. In this case, a 250-ml beaker was used. The method used to determine the density involves weighing 25, 50, 75, 100, and 125 mL of the liquid in the beaker. By plotting the volume of liquid along the horizontal axis and the total mass of beaker plus liquid on the vertical axis, it is possible to analyze the results. Option a is incorrect, as the x-intercept does not represent the weight of the beaker. It is important to note that the beaker's weight should be measured and subtracted from the total mass obtained from the experiment. Option b is also incorrect because the slope of the line is dependent on the identity of the liquid being used.
Option c is correct, as the y-intercept represents the weight of the empty beaker. This value is crucial in determining the total mass of the liquid. Finally, option d is incorrect because the line will not pass through the origin, and option e is also incorrect because the slope of the line will vary depending on the identity of the liquid. In summary, the correct answer is c.
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What is the total pressure of a mixture of he and h2 if the partial pressures are 320 mm hg and 800 mm hg respectively
Answer:
1120 mm Hg
plus give brainliest
a pore that simultaneously transports two different molecules in different directions is called
A pore that simultaneously transports two different molecules in different directions is called an antiporter. Antiporter is a type of membrane protein that facilitates the exchange of two different molecules or ions across biological membrane in the opposite directions.
A type of membrane transport protein that facilitates the exchange of two molecules across cell membrane, where one molecule is transported into the cell while the other molecule is transported out of the cell is known as an antiporter. This process is important for maintaining the balance of various ions and molecules inside and outside cell.
So, a pore that simultaneously transports two different molecules in opposite directions is called an "antiporter."
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calculate the number of moles in positive and negative ions in 1.75 moles of calcium fluoride quizlet
CaF₂ ⇒ Ca²⁺ + 2F⁻
1.75 1.75 3.5
A 0. 580 g ample of odium chloride i diolved in water and react with 3. 50 g of lead(I) nitrate in aqueou olution. If 1. 20 g of precipitate i obtained from the reaction, what i the percentage yield?
When nitrate solution of metal X reacts with sodium chloride then white precipitate is formed then metal X is Ag
AgNO 3 +NaCl→AgCl↓(whiteppt)+NaNO 3Aqueous nitrate solution of metal X react with Hypo-phosphorous acid to produce
Z3 PO 4 .4AgNO 3+H 3 PO 2 +2H 2 O→ ZH 3 PO 4 +4Ag+4HNO 3
Lead (II) nitrate solutions that have sodium chloride added will produce a white precipitate of (relatively) insoluble lead chloride. for chlorophyll. Together, opposites are pulled. Harmful energy is drawn to positive energy. When Pb(NO3)2(aq) and NaCl(aq) are combined, PbCl2(s) and NaNO3 precipitate (aq). Give an explanation for why there is no response when solid sodium chloride and solid lead nitrate come into contact. If both substances are solids, nothing will happen; they will merely combine and have no effect. Lead (II) and nitrate establish ionic connections with one another since they don't contain reactive ions in their solid state.
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WILL MARK BRAINIEST!!
NO LINKS!! Which of the follow can NOT be possible
error that occurs during a lab experiment?
human error
O pure reactants were used
unexpected products were produced
the reaction didn't go to completion
Answer:
0 pure reactants
Explanation:
hope this helps!
When elements are arranged according to increasing atomic number, there is a repeating, regular pattern of properties
This is called
periodic law
group
periodic table
family
Answer:
grpup
Explanation:
napagaralan namin yan
Why Aluminium oxide has higher melting point than Alumunium Chloride?
Answer:
They have high melting points . They have ionic
giant lattice structures : strong force of attraction between inland so have high melting points . They are iconic because of large electronegativity differences between the metal and oxygen ....Aluminum oxide (Al203) is ionic but does show some covalent character.
how much co(g) is required to completely react with 22.55 g fe2o3? if 15.32 g fe(s) are produced, what is the % yield?
11.87 g of CO(g) is required to completely react with 22.55 g Fe₂O₃(s) to produce 15.32 g Fe(s). The percent yield of the reaction is 97.15%.
The balanced equation for the reaction between CO(g) and Fe₂O₃(s) is:
Fe₂O₃(s) + 3 CO(g) -> 2 Fe(s) + 3 CO₂( g)
To determine how much CO is required to completely react with 22.55 g of Fe2O3, we need to use the stoichiometry of the reaction.
From the balanced equation, we know that for every 1 mole of Fe₂O₃(s) that reacts, 3 moles of CO(g) are consumed. To convert mass to moles, we use the molar mass of Fe₂O₃(s), which is 159.69 g/mol.
22.55 g Fe2O3 / 159.69 g/mol = 0.1412 moles of Fe2O3
From the balanced equation we know that for every 1 mole of Fe₂O₃(s), 3 moles of CO(g) is required, so we can calculate the moles of CO(g) needed for the reaction:
0.1412 moles Fe₂O₃(s) (3 moles of CO(g) / 1 mole of Fe₂O₃(s)) = 0.4236 moles of CO(g)
To get the mass of CO(g), we can convert the moles to grams using the molar mass of CO(g), which is 28.01 g/mol.
0.4236 moles of CO(g)(28.01 g/mol) = 11.8660 = 11.87 g of CO(g)
To find the % yield, we divide the actual yield (15.32 g Fe(s)) by the theoretical yield (mass of Fe(s) produced from all the Fe₂O₃(s) consumed) and multiply by 100.
Theoretical yield of Fe(s) = mass of Fe₂O₃(s) consumed(mass of Fe(s) produced from 1 mol Fe₂O₃(s) / mol of Fe₂O₃(s) consumed)
= 22.55 g Fe₂O₃(s) (55.85 g Fe(s) / mol Fe(s)) (2 mol Fe(s) / 1 mol Fe₂O₃(s)) (1 mol Fe₂O₃(s) / 159.69 g Fe₂O₃(s)) = 15.77 g Fe(s)
% yield = (15.32 g Fe(s) / 15.77 g Fe(s)) x 100 = 97.15%
So, 11.87 g of CO(g) is required to completely react with 22.55 g Fe₂O₃(s) to produce 15.32 g Fe(s) and the % yield of the reaction is 97.15%.
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Identify the balanced chemical equation that represents a decomposition reaction.
2Fe(OH) 3 ⟶ 2FeO 3 + H 2O
CuSO 4 ⟶ CuO + 2SO 3
2Fe(OH) 3 ⟶ Fe 2O 3 + 3H 2O
P 4 + 3O 2 ⟶ P 2O 3
Identify the balanced chemical equation that represents a decomposition reaction.
2Fe(OH) 3 ⟶ 2FeO 3 + H 2O
CuSO 4 ⟶ CuO + 2SO 3
2Fe(OH) 3 ⟶ Fe 2O 3 + 3H 2OP 4 + 3O 2 ⟶ P 2O 3
Explanation:
Answer:
Option C
Explanation:
A decomposition reaction is a type of reaction in which one reactant breaks down in to two or more products.
Here in option C
On both reactant and products side
Fe=2O=6H=6Hence balanced
Neutral atoms & charged atoms has
equal number of electrons
Answer:
wrong.
Explanation: charged atoms have have more electrons than neural because they charge it . a neural atom has eaqual number of electrons and neutrons.
hope this helps(^人^)
4. Which of the following ideas is NOT true? *
A. Atoms of the same element have a constant number of neutrons.
B. Atoms have a central, positively charged nucleus.
C. Atoms may gain or lose electrons to become ions.
D. Atoms of the same element have a constant number of protons.
Answer:
c
Explanation:
Answer:
the answer of the question is C
A solution of NaCl was prepared in the following manner: 0.0842 g of NaCl is massed out on an analytical balance. The solid is transferred to a 25.00 mL volumetric flask. Deionized water is added to the flask such that the bottom of the meniscus is at the line. A 1.00 mL aliquot of the stock solution is transferred to a 50.00 mL volumetric flask using a volumetric pipet and diluted to volume. 6. Calculate the concentration of NaCl in the resulting solution in mg/L NaCl. (answer = 67.4 mg/L) 7. Calculate the concentration of NaCl in the resulting solution using propagation of error through the calculation. Use the manufacturer's tolerance values as the absolute error. The tolerances can be found in Chapter 2 of the Harris text. Assume a Class 1 balance and Class A glassware. Treat the tolerances as random error. (answer = 67.4+0.4 mg/L) 8. Identify 2 possible sources of random (indeterminate) error. Identify 2 possible sourses of systematic (determinate) error.
Two possible sources of systematic (determinate) error in the experiment are; Incorrect calibration of volumetric glasswareIncorrect mass of NaCl
To calculate the concentration of NaCl in the resulting solution in mg/L NaCl, we can use the formula; Concentration (mg/L) = (Mass of solute ÷ Volume of solution in L) × 1000 g / 1 mg NaCl is present in the stock solution of 25 mL. So, the mass of NaCl in the solution would be;0.0842 g ÷ 25 mL = 0.00337 g/mL. Now, in the resulting solution, a 1.00 mL aliquot of the stock solution is transferred to a 50.00 mL volumetric flask and diluted to volume. Therefore, the volume of the resulting solution is 50.00 mL. We will substitute these values in the formula, Concentration (mg/L) = (0.00337 g/mL ÷ 50 mL) × 1000 g / 1 mg concentration (mg/L) = 67.4 mg/L. Therefore, the concentration of NaCl in the resulting solution in mg/L NaCl is 67.4 mg/L.7. Concentration = 67.4 mg/LTolerance = 4.28 mg/LTotal concentration = 67.4 + 4.28 mg/L = 71.68 mg/LWe round off this value to one decimal place; Total concentration = 71.7 mg/LTherefore, the concentration of NaCl in the resulting solution using propagation of error through the calculation is 67.4+0.4 mg/L.8. Two possible sources of random (indeterminate) error in the experiment are; Errors in temperature measurement. Errors in measurement of water volume. Two possible sources of systematic (determinate) error in the experiment are; Incorrect calibration of volumetric glasswareIncorrect mass of NaCl.
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Draw the lewis structure of CH₃F and then determine if the molecule is polar or nonpolar.
the lewis structure of CH₃F and then determine if the molecule is polar or nonpolar. are called Reconstruction debate that had federalism debate that had been an issue since the 1790s.
Reconstruction failed by most other measures: Radical Republican legislation ultimately failed to nonpolar former slaves from white persecution and failed to engender fundamental changes to the social fabric of the South. When President Rutherford B. federalism debate that had been an issue nonpolar the 1790s almost mediately . Hayes removed federal troops from the South in 1877, former Confederate officials and slave returned to With the support of a conservative Supreme Court, these newly empowered white southern politicians passed black codes, voter qualifications, and other anti-progressive legislation to reverse the rights that blacks had gained during Radical Reconstruction. The U.S. Supreme Court bolstered this federalism anti-progressive movement federalism with decisions in the Slaughterhouse Cases, the Civil Rights Cases, and United States v.
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Water is kept in a vessel at a temperature of 30°C. What would happen if a hot metal ball having a temperature of 70°C is dropped in it. Mention the heat flow. Give reasons
:
Answer:As the ball is at 70 degree celsius and the water is at 30 degree celsius, the heat flow will take place from the hot metal ball towards the water which is at low temperature.
Explanation:
Therefore, there will be a decrease in the temperature of the metal ball.
Calculate the volume of 100. grams of oxygen gas (O₂) at 25.0°C and a pressure of 1.25 atm.
Ideal gas law states
PV = n(RT)V is volume (L), P is pressure (atm), R is universal gas constant: 0.0821 L·atm/mol· K, n is number of moles, T is temperature in Kelvin
Here given:
\(\blacksquare\) mass of O₂ : 100 gram
\(\blacksquare\) moles: mass/molar mass = 100/32 = 3.125 moles
\(\blacksquare\) 25.0 °C = (25+273.15) = 298.15 K
\(\blacksquare\) pressure: 1.25 atm
Volume:
\(\boxed{\sf V=\dfrac{nRT}{P}}\)
\(\Rightarrow \sf V=\dfrac{(3.125 \ x \ 0.0821 \ x \ 298.15 )}{1.25}\)
\(\Rightarrow \sf V=61.195 \ L\)
\(\Rightarrow \sf V=61.2 \ L \ \ \ (rounded \ to \ nearest \ tenth)\)
Additional Explanation:
Volume can be counted in multiple units.In Liters: 61.2 Liters
In cubic meter: 0.061163 m³
In cubic centimeter: 61,163.5 cm³
Match up the characteristics below with the type of molecular bond they describe. Bonds found in Halite (between Na+ and Cl-) Bonds found between Si and O in the Si-O tetrahedron Bonds inside the water molecule (between the H and O ) Bonds that exist between two water molecules Strongest bond type Weakest bond type Bonds that are used by water to dissolve sal
The characteristics and the type of molecular bond they describe:
1. Bonds found in Halite (between Na⁺ and Cl⁻): Ionic bond
2. Bonds found between Si and O in the Si-O tetrahedron: Covalent bond
3. Bonds inside the water molecule (between the H and O): Covalent bond
4. Bonds that exist between two water molecules: Hydrogen bond
5. Strongest bond type: Covalent bond
6. Weakest bond type: Van der Waals bond
7. Bonds that are used by water to dissolve salt: Ionic bond
The ionic bond is a type of molecular bond found in halite (between Na⁺ and Cl⁻). The Si-O tetrahedron is held together by a covalent bond. The bond inside the water molecule (between the H and O) is also a covalent bond. The hydrogen bond is the type of bond that exists between two water molecules. The covalent bond is the strongest bond type, while the van der Waals bond is the weakest bond type. Water uses the ionic bond to dissolve the salt.
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38
Both ionization and dissociation produce ions of the solute in solution.
How do the two processes differ? Write two differences. *
Answer:
Detail is given below
Explanation:
Differences:
Ionization involves the formation of ions while in dissociation substance are break into atoms, ions or molecules.
In ionization atoms and molecules gain positive or negative charge.
While in dissociation positive and negative ions are not essentially formed substance could be break into neutral small particles.
Ionization occur in covalent compounds while dissociation occur in ionic compound.
Ionization example:
Cl + e⁻ → Cl⁻
Dissociation example:
NaCl → Na⁺ + Cl⁻
Here sodium and chloride ions are formed but in sodium chloride these ions were already present.
Another example:
N₂O₄ → 2NO₂
Sulphur and Magnesium are separately burnt in air. Name the products formed. When these products are dissolved in water and the solutions obtained are tested with litmus, what will be the result? Why?
Answer: Magnesium turns red litmus blue and sulphur turns blue litmus red.
Explanation:
When a metal reacts with oxygen present in air, it forms basic oxide which simply means when they react with water, they form basic solution.
The chemical equation for the burning of magnesium (metal) in air and reaction with water of the product so formed are as follows:
\(2Mg+O_2\rightarrow 2MgO\)
\(MgO+H_2O\rightarrow Mg(OH)_2\text{ (base)}\)
When a non- metal reacts with oxygen present in air, it forms acidic oxide which simply means when they react with water, they form acidic solution.
The chemical equation for the burning of sulphur (non-metal) in air and reaction with water of the product so formed are as follows:
\(S+O_2\rightarrow SO_2\)
\(SO_2+H_2O\rightarrow H_2SO_3\text{ (acid)}\)
There are 2 types of litmus:
Red litmus: They turn the solution blue when dipped in basic solution.Blue litmus: They turn the solution red when dipped in acidic solution.Therefore, here, magnesium forms a basic solution, therefore it will turn red litmus blue whereas sulphur forms an acidic solution, so it will turn blue litmus red.
Has anyone taken and or has any pointers on taking the
industrial electricity NOCTI # 2050.
Individuals who have studied industrial electricity will have a greater knowledge of electrical systems, circuits, and components, as well as the ability to troubleshoot and repair them. Here are a few pointers on how to prepare for and pass the Industrial Electricity NOCTI # 2050 exam:To prepare for the Industrial Electricity NOCTI # 2050, you should get hold of a reliable textbook or a study guide on industrial electricity.
Some good texts include Electrical Motor Controls for Integrated Systems, Electrical Wiring Residential, Electrical Systems Design, and Conduit Bending and Fabrication. As you read through the textbook, make notes and attempt the end-of-chapter review questions and problems.Read and study the test specifications. Test specifications outline what will be covered on the exam. Be sure you understand each of the test specifications and are capable of demonstrating the required skills.You may participate in a NOCTI practice test session. This can help you get familiarized with the exam pattern, and allow you to get a better understanding of the type of questions you can expect. You'll also receive feedback on how to improve your results.You can take online practice tests and quizzes. Several websites offer free online practice tests.
Take as many practice tests as you can to build your confidence. This will help you familiarize yourself with the test structure, type of questions, and time management strategies.Keep practicing. Keep practicing on sample questions and problems. You can also join a study group to work with other individuals who are preparing for the Industrial Electricity NOCTI # 2050.
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A sample of gas occupies 75.5 mL at -14.2°C. What volume does the sample occupy at 146.7 °C?
Which of the following is true of pericyclic reactions? O A. they are concerted reactions O B. proceed via a cyclic transition state o C. no intermediates are formed O D. all of these
The following is true of pericyclic reactions: D. All of these statements are true of pericyclic reactions. The correct option is D.
Pericyclic reactions are a class of organic reactions that involve the simultaneous rearrangement of sigma bonds and pi bonds in a cyclic transition state. These reactions exhibit several characteristic features.
A. They are concerted reactions: Pericyclic reactions occur in a single step, without the formation of any intermediates. The reactants rearrange their bonds simultaneously to form the products.
B. They proceed via a cyclic transition state: During the reaction, the reactant molecules pass through a cyclic transition state where the rearrangement of bonds takes place. This cyclic transition state is often visualized as a ring-shaped structure.
C. No intermediates are formed: As pericyclic reactions are concerted, they do not involve the formation of any intermediates along the reaction pathway.
Therefore, all of these statements are true of pericyclic reactions. They are concerted, proceed via a cyclic transition state, and do not involve intermediates. These characteristics make pericyclic reactions distinct from stepwise reactions that involve the formation of intermediates. The correct option is D.
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What is true about graphs? a. They are created from data tables b. Give a visual representation of the data c. Valid conclusions depend on clear interpretation of the data d. All of the above
Here, the true statement about the graph is, option: (d) All of the above is correct .
A graph is a diagram that depicts the connections between two or more objects. A pie chart is a type of graph. The data can be displayed using graphs or tables. Both can be used to draw conclusions about the data as well. Both should be set up such that details regarding the frequencies of the various data categories may be discovered.Therefore ,these visual representations include tables and graphs. They are employed to arrange data in order to highlight patterns and correlations. This information is displayed as a shape on a graph. To present the results of their research, scientists and researchers frequently employ tables and graphs.
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