(1/2)^3 is the fraction of a sample after 3 half lives
The unique characteristic of the amino acid cysteine is _____.
Answer: since it has a very reactive sulfhydryl group at its side chain. This puts cysteine in special position that cannot be replaced or substituted by any other amino acid. Because disulfide bridges formed by cysteine residues are permanent component of protein primary structure.
Explanation:
In chemistry, there are three commonly encountered theories to explain what acids and bases are and what they do. Name these theories and describe what each one states about acids and bases. Give an example to help describe each of the types. Make sure to explain how these theories differ from each other. (Properties of Acids and Bases)
Answer: The theories are such that if any chemical produce H+ ion then it is an acid and if the chemical produces OH- ion then it's a base.
Explanation:
sorry I am not that much knowledgeable like all of you
What is the total number of moles of hydrogen gas contained in 9.03 × 1023 molecules?
Answer:
1.5 mol.
Explanation:
It is known that every 1.0 mole of compound or element contains Avogadro's number (6.022 x 10²³) of molecules or atoms.Using cross multiplication:
1.0 mole of H₂ contains → 6.022 x 10²³ molecules.
??? mole of H₂ contains → 9.03 x 10²³ molecules.
∴ The no. of moles of H₂ contains (9.03 x 10²³ molecules) = (1.0 mol)(9.03 x 10²³ atoms)/(6.022 x 10²³ atoms) = 1.5 mol.
To find the total number of moles of hydrogen gas in 9.03 × 10²³ molecules, you divide the number of molecules by Avogadro's number (6.022 × 10²³ molecules/mole), resulting in approximately 1.5 moles of hydrogen gas.
To calculate the total number of moles of hydrogen gas (H₂) from the given number of molecules, we use Avogadro's number, which is 6.022 × 10²³ molecules per mole. The number of moles (n) is given by the formula:
n = {Number of molecules} ÷ {Avogadro's number}
Substituting our values, we get:
n = (9.03× 10²³ molecules ÷ 6.022 × 10²³ molecules/mole) ≈ 1.5 moles
Therefore, there are approximately 1.5 moles of hydrogen gas contained in 9.03 × 10²³ molecules of hydrogen gas.
NaOH + HCl → NaCl + H2O
An instructor is planning to demonstrate this reaction to a class as an example of a neutralization reaction. She does a test run, using NaOH pellets and 1.0 M HCl. The reaction mixture spatters. She concludes that this is unsafe; the reaction rate is too fast. How can she slow it down?
A)
heat the HCl
B)
use 0.2 M HCl
C)
add a catalyst
D)
grind the NaOH pellets to a powder
The correct answer is B).
Answer:
B) use 0.2 M HCl
Explanation:
Lowering the concentration of a reactant will slow down the rate of reaction. If she would use 0.2 M HCl, the reaction rate will be slower than with 1.0 M HCl. The other choices would increase the rate of reaction, making it even more dangerous.
Only element in the halide family that is a liquid. What is this element
Answer:
Bromine.
Explanation:
That is bromine which is a dark red vaporous liquid with a bad smell. There are only 2 elements which are liquid at room temperature, bromine and mercury.
Which element would form an ionic bond with Oxygen?
Nitrogen
Lithium
Helium
Carbon
Answer:
Lithium
Explanation:
An ionic bond requires one metal and one nonmetal. Out of all the choices given, Lithium is the only one that is a metal.
One gram of salt in 100 liters of water could be considered a _______________________ solution. A) concentrated B) dilute C) saturated D) supersaturated
Answer:I believe your answer would be option B) dilute. Hope this helps.
Explanation:
The correct answer is B) Dilute
Explanation:
In a solution, the proportions of the solute vs the solvent determine the type of solution that includes dilute/concentrated or unsaturated, saturated and supersaturated. In the case of a dilute solution, this occurs if there is a small amount of the solute in comparison to the amount of solvent, which makes it possible to add more solute as this can be dissolved. This type of solution applies to the case presented because one gram of salt (solute or substance dissolved) is a small quantity of solute in comparison to the amount of solvent (the substance that dissolves) that in this case is 100 liters of water. Thus, in this case, there is a dilute solution.
Cholesterol is an example of a(n) _____.
monosaccharide polysaccharide
lipid
enzyme
Cholesterol is an example of a lipid.
Cholesterol is an example of a(n) lipid. Hence, option C is correct.
What is a lipid?A lipid is any of various organic compounds that are insoluble in water.
Cholesterol is one of several types of fats (lipids) that play an important role in your body.
Cholesterol is a waxy substance found in all cells of the body.
The body needs it to make hormones, Vitamin D, and substances that aid in digestion.
The liver makes all the cholesterol needed for these functions.
Hence, option C is correct.
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How many grams are in 1.946 moles of nacl
Answer:
113.8g
Explanation:
Statement of problem: mass of 1.946mole of NaCl
Given parameters:
Number of moles of NaCl = 1.946mole
Unknown: mass of NaCl
Solution
To find the mass of NaCl, we apply the concept of moles which expresses the relationship between number of moles and mass according to the equation below:
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
To find the molar mass of NaCl:
the atomic mass of Na = 23g
atomic mass of Cl = 35.5g
Molar mass of NaCl = (23 + 35.5) = 58.5gmol⁻¹
Mass of NaCl = Number of moles x molar mass of NaCl
Mass of NaCl = 1.946 x 58.5 = 113.8g
There would be approximately 113.72 grams in 1.946 moles of NaCl. This is calculated by using the molar mass of NaCl (58.44 g/mol) and multiplying it by the number of moles given.
Explanation:To find out how many grams are in 1.946 moles of NaCl, you need to use the molar mass of NaCl. The molar mass is the mass of one mole of a substance and for NaCl, it is calculated by adding the atomic masses of Sodium (Na) and Chlorine (Cl), which is approximately 58.44 grams per mole. Therefore, to find out the mass in grams of 1.946 moles of NaCl, you multiply 1.946 moles by the molar mass of NaCl, 58.44 g/mol.
1.946 moles NaCl * 58.44 g/mol NaCl = 113.72 grams NaCl
So, 1.946 moles of NaCl is approximately equal to 113.72 grams.
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what is the volume of 2.00 moles of ideal gas at 25'c and 121.59 kpa of pressure
Answer:
40.73 L.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm (P = 121.59 kPa/101.325 = 1.2 atm).
V is the volume of the gas in L (V = ??? L).
n is the no. of moles of the gas in mol (n = 2.0 mol).
R is the general gas constant (R = 0.082 L.atm/mol.K),
T is the temperature of the gas in K (T = 25°C + 273 = 298 K).
∴ V = nRT/P = (2.0 mol)(0.082 L.atm/mol.K)(298 K)/(1.2 atm) = 40.73 L.
a solution containing the maximum amount of solute that can be dissolved at a given temperature is ____
Answer:
A saturated solution
Explanation:
A saturated solution is a solution which has dissolved as much solute as it can dissolve at a given temperature. If more solutes are added, a saturated solution would not dissolve it. Such solution has reached its carrying capacity.
If the temperature changes, the solution might be able to dissolve more solutes in it.
An undersaturated solution is one in which does not contain enough dissolved solutes in it at a given temperature.
Balance the following equation; then determine how many grams of CO2 will be produced when 40.0 mol of CO reacts with Fe2O3.
___Fe2O3(s) + ___CO(g) —> ___Fe(l) + ___CO2(g)
To balance the equation Fe2O3 + 3CO → 2Fe + 3CO2, we need to ensure that the number and type of atoms are the same on both sides. Using the balanced equation, we can determine that when 40.0 mol of CO reacts with Fe2O3, 1,760 g of CO2 will be produced.
Explanation:To balance the equation Fe2O3 + 3CO → 2Fe + 3CO2, we need to ensure that the number and type of atoms are the same on both sides.
Fe2O3 + 3CO → 2Fe + 3CO2
Now, to determine how many grams of CO2 will be produced when 40.0 mol of CO reacts with Fe2O3, we use the balanced equation to set up a conversion factor. The stoichiometric ratio for CO2 to CO is 3:3. So, for every 3 moles of CO, 3 moles of CO2 are produced.
Therefore, using the conversion factor:
40.0 mol CO × (3 mol CO2/3 mol CO) = 40.0 mol CO2
Converting moles to grams, we can use the molar mass of CO2:
40.0 mol CO2 × (44.01 g CO2/1 mol CO2) = 1,760 g CO2
The decomposition of N2O5 can be described by the equation.2N2O5 (soln) ---> 4NO2 (soln) + 2 (g)Given this data for the reaction at 45 degrees C in carbon tetrachloride solution, calculate the average rate for each successive time interval.t(s) [N2O5] (M)0 2.10195 1.86556 1.48825 1.25Interval: 0 s to 195 sReaction rate= _____M/s195 s to 556 sReaction rate= _____M/s556 s to 825 sReaction rate= _____M/s
Answer:
Rate 1 => 1.2E-3 M/s, Rate 2 => 1.05E-3 M/s, Rate 3 => 8.9E-4 M/s
Explanation:
Rate = Δ[N₂O₅]/Δtime
Rate 1 = (1.86556 - 2310195)M/(195 - 0)s = -1.2 x 10⁻³ M/s
Same for Rates 2 & 3.
The rate of reaction can be calculated in terms of the consumption of the reactants in the reaction.
In the given equation [tex]\rm N_2O_5[/tex] has been the reactant that has been used 2 moles.
The rate of the reaction has been = [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{dN_2O_5}{dt}[/tex]
The reaction rate for time interval 0s - 195 sec, can be given by:Reaction rate = [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{1.86556\;-\;2.10195}{195\;s\;-\;0\;s}[/tex]
= [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{-0.23639}{195\;s}[/tex]
= 0.0006 M/s.
The rate of reaction for time interval 195s - 556s, can be given by:Reaction rate = [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{1.48825\;-\;1.86556}{556\;s\;-\;195\;s}[/tex]
= [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{-0.416735}{361\;s}[/tex]
= 0.0005 M/s
The rate of reaction for time interval 556s - 825s, can be given by:= [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{1.25\;-\;1.48825}{825\;s\;-\;556\;s}[/tex]
= [tex]\rm -\dfrac{1}{2}\;\times\;\dfrac{-0.23825}{269\;s}[/tex]
= 0.0004 M/s.
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The unique characteristic of the amino acid cysteine is _____.
a high level of acidity
its ability to form hydrogen bonds
its ability to form disulfide bridges a second amino group
Answer:
C. the last one
Explanation:
Cysteine's unique characteristic is its ability to form disulfide bridges, covalent bonds that provide structural stability to proteins. The formation of these bridges is a unique property of cysteine among the amino acids, even though it, like others, can form hydrogen bonds.
Explanation:The unique characteristic of the amino acid cysteine is its ability to form disulfide bridges. These bridges are covalent bonds that provide structural stability to proteins. While cysteine is capable of forming hydrogen bonds like other amino acids, its special characteristic is indeed the formation of these disulfide bridges. Two cysteine residues can come together to form a disulfide bridge, helping to stabilize the three-dimensional structure of the protein. It is notable that hydrogen bonds are weak interactions that occur broadly between many different molecules, but the covalent bonding of disulfide bridges is a unique property of cysteine within the amino acid series.
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Which of the following could cause a gaseous substance to liquify?
F, An increase in pressure
G, An increase in volume
H, An increase in temperature
J, A decrease in number of moles
Answer:
f
Explanation:
pressure
When taphonomy records show a short PMI and warm, humid conditions, the degree of certainty is probably _____.
not even closedefinitelowhigh
The degree of certainty is high.
Answer:
The correct answer is "high".
Explanation:
Taphonomy is the science that studies how organic matter decays and becomes fossilized. Forensic taphonomy is used to estimate the characteristics of a person's death, with tests with levels of certainty depending on multiple factors. If a sample has a short PMI (Postmortem Interval), warm and humid conditions, the degree of certainty is probably high because the conditions are ideal to preserve an organic sample.
What is the most abundant chemical element in the universe?
hydrogen is the most
Hydrogen is the most abundant element in the universe, making up about 90% of atoms. Helium is the second most abundant. These two elements dwarf the prevalence of all other elements combined.
The most abundant chemical element in the universe is hydrogen. Accounting for approximately 90% of atoms, hydrogen's prevalence surpasses all other elements. This elemental dominance extends to the composition of stars, including our sun, where hydrogen serves as a primary fuel for stellar processes. Following hydrogen, helium constitutes most of the remaining 10%, and all other elements appear in far lesser quantities. Hydrogen plays a significant role on Earth as well, being a part of countless compounds such as water, which is the most widespread compound of hydrogen on our planet.
A balanced chemical equation used to prepare ammonium carbonate, (nh4)2co3 , is: 2 n h 3 ( g ) + c o 2 ( g ) + h 2 o ( l ) ⟶ ( n h 4 ) 2 c o 3 which choice of reactant quantities shown below would result in the greatest amount of ammonium carbonate being formed?
Final answer:
The greatest amount of ammonium carbonate is produced when reactants NH3, CO2, and H2O are used in the mole ratio of 2:1:1, ensuring an excess of water.
Explanation:
To determine the reactant quantities that would result in the greatest amount of ammonium carbonate being formed, we must look at the stoichiometry of the balanced chemical equation provided:
2NH3(g) + CO2(g) + H2O(l) → (NH4)2CO3
According to this equation, therefore, the greatest amount of ammonium carbonate will be produced when reactants are supplied in the mole ratio of 2:1:1 for NH3:CO2:H2O, respectively. Choosing reactant quantities that provide ammonia and carbon dioxide in at least this ratio, while ensuring an excess of water, would maximize production of ammonium carbonate.
Question 9(Multiple Choice Worth 4 points)
(08.01 LC)
What happens to water when it warms above 4 °C?
It contracts.
It forms ice.
Its density decreases.
Its composition changes.
Answer: It contracts and its density decreases, I believe.
Explanation:
Answer:
its density decreases
Explanation:
How many moles of aluminum are needed to react completely with 1.2 mol of feo
Answer:
0.80 mol AlExplanation:
1) Word reaction:
Aluminum + ferrous oxide → aluminum oxide + ironThis is a single replacement reaction, in which aluminum, a more acitve metal than iron, replaces the iron in the ferrous oxide to form aluminum oxide and iron.
2) Skeleton chemical equation:
Al + FeO → Al₂O₃ + Fe3) Balanced chemical equation:
Add the coeffcients to comply with the law of conservation of mass:
2Al + 3FeO → Al₂O₃ + 3Fe4) Mole ratio of Al and FeO:
2 mol Al : 3 mol FeO5) Set a proportion with the unkown and solve:
x / 1.2 mol FeO = 2 mol Al / 3 mol FeOx = 1.2 mol FeO × 2 mol Al / 3 mol FeO = 0.80 mol Al ← answerA solution containing HCl and the weak acid HClO2 has a pH of 2.4. Enough KOH (aq) is added to the solution to increase the pH to 10.5. The amount of which of the following species increases as the KOH (aq) is added? A)Cl- (aq) B)H+ (aq) C)ClO2- (aq) d)HClO2 (aq)
Answer:
[tex]\boxed{\rm \text{[ClO$_{2}^{-}$] increases}}[/tex]
Explanation:
At the beginning, you have two reactions happening:
[tex]\rm HCl + H$_{2}$O$ $\, \longrightarrow \,$ H$_{3}$O$^{+}$ + Cl$^{-}$\\\rm HClO$_{2}$ + H$_{2}$O$ $\, \rightleftharpoons \,$ H$_{3}$O$^{+}$ + ClO$_{2}^{-}$[/tex]
As you add KOH(aq), it does two things:
It increases the volume of the solution. It reacts with the hydronium ions to form water.A) The HCl is completely ionized. The Cl⁻ does not react, but it is diluted when the volume of the solution increases. [Cl⁻] decreases.
B) The KOH reacts with the H⁺ and removes it from the solution. [H⁺] decreases.
C) When all the H⁺ from the HCl has been neutralized, the KOH starts neutralizing the H⁺ from the HClO₂. According to Le Châtelier's Principle, more HClO₂ will dissociate to replace the decreased H⁺. [HClO₂] decreases.
D) As HClO₂ reacts, it forms ClO₂⁻. [tex]\boxed{\rm \textbf{[ClO$_{2}^{-}$] increases}}[/tex]
The amount of ClO2- increases as aqueous KOH is added.
AcidsAcids are substances which donate hydrogen ions or protons in aqueous solutions. Acids can either be strong or weak.Strong acids ionize completely in solution to produce hydrogen ions.
Weak acids only ionize partially in solution to produce hydrogen ions.
HCl is a strong acid and ionizes completely to produce hydrogen and chloride ions.HClO2 is a weak acid and only ionizes partially.When aqueous KOH is added to a mixture of HCl and HClO2, the follow occurs:
Hydrogen ions from HCl are removed, hence H+ reduces.Cl- amount remains the same but is diluted as the volume of solution increases.ClO2- increases as the hydrogen ions are removed from the partially ionized HClO2.HClO2 decreases due to equilibrium shift towards formation of more H+ and ClO2-Therefore, the amount of ClO2- increases as aqueous KOH is added.
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if 5 gases in a cylinder each have a partial pressure of 2.50 atm ,what is the total pressure exerted by the gases?
Answer:
12.5 atm.
Explanation:
The total pressure of a mixture of gases can be defined as the sum of the pressures of each individual gas:Ptotal = P1 + P2 + … + Pn.
∴ Ptotal = P of gas 1 + P of gas 2 + P of gas 3 + P of gas 4 + P of gas 5.
∴ Ptotal = 5(2.5 atm) = 12.5 atm.
How many moles of Al(OH)^3 is in 12.4 g of aluminum hydroxide?
Answer:
0.1589 mol ≅ 0.16 mol.
Explanation:
Knowing that the no. of moles can be calculated using the relation:no. of moles (n) = mass/molar mass
mass of Al(OH)₃ = 12.4 g & molar mass of Al(OH)₃ = 78.01 g/mol.
∴ n = mass/molar mass = (12.4 g)/(78.01 g/mol) = 0.1589 mol ≅ 0.16 mol.
Question 1(Multiple Choice Worth 4 points)
(08.02 HC)
How many liters of 4.0 M NaOH solution will react with 0.30 liters 4.0 M H2SO4?
H2SO4 + NaOH → Na2SO4 + H2O
1.6 L
1.2 L
0.90 L
0.60 L
Answer:
0.60 L.
Explanation:
How many moles of [tex]\rm H_2SO_4[/tex]?
[tex]n(\mathrm{H_2SO_4}) = c\cdot V = 4.0\times 0.30 = \rm 1.2\; mol[/tex].
How many moles of [tex]\rm NaOH[/tex] will react with all that 1.2 moles of [tex]\rm H_2SO_4[/tex]?
Balance the equation:
[tex]\rm H_2SO_4 + 2\; NaOH \to Na_2SO_4 + 2\;H_2O[/tex].
The coefficient in front of [tex]\rm H_2SO_4[/tex] is 1. The coefficient in front of [tex]\rm NaOH[/tex] is 2. Hence the ratio:
[tex]\displaystyle \frac{n(\mathrm{NaOH})}{n(\mathrm{H_2SO_4})} = \frac{2}{1} = 2[/tex].
Therefore
[tex]\displaystyle n(\mathrm{NaOH}) = \frac{n(\mathrm{NaOH})}{n(\mathrm{H_2SO_4})} \cdot n(\mathrm{H_2SO_4}) = 2\times 1.2 = \rm 2.4\;mol[/tex].
What will be the volume of the [tex]\rm NaOH[/tex] solution?
[tex]\displaystyle V(\mathrm{NaOH}) = \frac{n}{c} = \frac{2.4}{4.0} = \rm 0.60\;L[/tex].
Click the "draw structure" button to launch the drawing utility. draw the product of the reaction below. do not specify the stereochemistry of the product.
The question asks for the product structure of a reaction to be drawn using a utility. Somewhat, it isn't possible to provide a drawn response without the reaction details and the specific utility. However, in general, recognizing the reactants, the type of reaction, and consequently sketching the product guidance was given.
Explanation:The current question pertains to a chemical reaction product and the drawing of its structure using a specific utility. Unfortunately, without an image of the reaction and the platform's drawing utility unattainable here, an explicit 'drawn' response isn't feasible. However, the request to not specify stereochemistry suggests that your interest is mainly in the skeletal structure.
Generally, in organic chemistry, you'd discern the reactants, identify the type of reaction (such as addition, substitution, or elimination), and consequently draw the product by connecting atoms according to the reaction rules. The stereochemistry, which refers to the three-dimensional arrangement of the atoms, isn't a concern in this case.
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Any organism or particle that can cause an infectious disease is called a
bacteriavirusviroidpathogen
Answer:
PATHOGEN.
Explanation:
In biology, pathogen refers to any organism or particle that is capable of causing infectious diseases. Thus, all the microbes that cause diseases such as bacteria, virus, fungi, viroid, etc are collectively known as pathogen. The entrance of pathogen into the human body usually stimulate the immune system. The immune system functions by recognizing pathogens and by capturing and destroying them.
HELP ASAP PLEASE!!!
Explain why molecules of alkenes and alkynes must have at least two carbon atoms while alkanes may contain only one carbon atoms.
Answer:
Because alkenes and alkynes are defined as molecules with at least one double (in the case of alkenes) or triple (in the case of alkynes) bond between two carbon atoms, while alkanes have only single bonds between any pair of carbon atoms.Explanation:
Alkenes and alkynes are unsaturated molecules, because they have, at least, two adjacent carbon atoms bonded together by either a doubler or a triple bond: - C = C - or - C ≡ C -.
Hence, at least two carbon atoms are needed to form those double or triple bonds, while alkanes have only single bonds. The example of alkane with only one carbon atom is methane: CH₄, which is the most simple alkane.
The most simple alkene is CH₂ = CH₂, and the most simple alkyne is CH≡CH.
As you see, the very definition of alkenes and alkynes forces that those molecules must have at least two carbon atoms.
How has the work of chemists affected the environment?
A. A single chemical can sometimes both hurt and help the
environment.
B. The chemicals that chemists use can all be helpful to the
environment.
C. The work of some chemists causes environmental problems,
while the work of others tries to fix problems.
D. All chemists use chemicals that are bad for the environment.
The work performed by the chemists can be considered as the useful effect to fix a problem, while some work found to harm the environment. Thus, option C is correct.
Who are Chemists?Chemists are the group of individuals that deal with the drugs and the medicines. The research made the development of the new drugs and the compounds that are used by the population to treat several diseases.
The chemicals dealt by chemist are formed to be sensitive, and can be used to fix the problems, while sometimes the effect creates the compound that harm the environment.
Thus, option C is correct.
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Atoms that gain or lose electrons are called
Answer:
ions
Explanation:
An atom that has gained or lost an electron is called an ion. Ions are charged particles that have lost or added an electron to their outermost shell. Ions are the basis of any chemical reaction. The combination of ions leads to the formation of bonds between atoms and this results in molecules and compounds.
When atoms are in their ground state, they are otherwise neutral and such would not combine chemically. It is difficult to find elements in such form naturally. Atoms that have ionized by losing or gaining electrons would freely combine with one another in order to establish a more stable configuration.
The rate of a standard reaction is 0.01840 M/s at 25 oC. It is determined that this is too fast, and that the rate should be reduced to 0.0046 M/s. What temperature should the reaction be run at to achieve this? A. 45 oC B. 20 oC C. 15 oC D. 5 oC E. 0 oC
Hi there,
Your answer is given in the image attached above
Answer:
Option B. 20 oC
Explanation:
Thinking process:
The initial reaction takes place at: 0.01840 M/s at 25 oC.
However, the rate must be reduced to 0.0046 M/s.
It is most likely that a temperature of 20 °C is used her. This is because it offers sufficient kinetic energy to effect the reaction rate of the reaction substances.