Chapter 4 - Chemical Quantities and Chemical Reactions
Molecular mass is the
mass of a single molecule in units of amu
formula mass is the
mass of the formula unit of an ionic compound in units of amu
Converting from mass to particles is a two-step process:
mass to moles, then moles to particles
Law of conservation of mass
matter can be neither created nor destroyed
a bomb calorimeter
measures the change in enthalpy for a combustion reaction
The mass of one formula unit (empirical formula) of an ionic compound is...
the formula mass
the activation energy is released to the rate of a reaction
the greater the activation energy, the slower the reaection
The change in enthalpy, deltaH, is a measure of
the heat released or absorbed in a chemical reaction
Molar mass is a conversion between
the mass, in grams, or a substance and the number of moles of a susbtance
the molar mass of a compound is numerically equivalent to
the molecular mass or the formula mass, but in units of grams per mole (g/mol rather than amu)
Avogadro's number (6.02 x 10^23) represents
the number of atoms, ions, or particles in one mole of any substance. It can be used as a conversion between the number of moles of a substance and the number of atoms, molecules, or ions of a substance
A chemical reaction can proceed only when
the reactant molecules collied with enough energy and are in the correct spatial orientation
If heat is removed from an endothermic reaction,
the reaction will shift the left - more reactants will be produced
Which of the statements describe a mole? a. Avogadro's number of items b. the amount of a substance containing the same number of formula units as there are atoms in 12g of carbon c. 6.022 x 10^23 d. mass x acceleration
a. Avogadro's number of items b. the amount of a substance containing the same number of formula units as there are atoms in 12g of carbon c. 6.022 x 10^23
Which statements are true? a. When energy is transferred as heat from the system to the surroundings, deltaH is negative b. deltaH for an exothermic reaction is positive c. when energy is transferred as heat from the surroundings to the system, deltaH is negative d. a combustion reaction is exothermic e. deltaH for an endothermic reaction is positive f. The evaporation of water is an exothermic process
a. When energy is transferred as heat from the system to the surroundings, deltaH is negative d. a combustion reaction is exothermic e. deltaH for an endothermic reaction is positive
When a chemical reaction releases heat, where does this energy come from? a. breaking chemical bonds b. forming new chemical bonds c. atoms changing into other atoms d. from an energy diagram
a. breaking chemical bonds
If heat is added to an exothermic reaction (heat is a product),
the reaction will shift to the left - more reactants will be produced
equal number of each type of atom on each side of the equation is....
balanced
Every atom type in the reactions also appears in the products.... only the ______ change
bonds
Many reactions are reversible:
both the forward and reverse reactions occur simultaneously
In a chemical reaction, bonds....
break and new bonds are formed, producing different compounds or elements
Catabolic pathways
breakdown
Food energy is measured by
- combusting a food sample in the presence of oxygen - all the energy released is absorbed by the water - the calories absorbed by the water were given off by the food, allowing the calories in the food to be determined
From a balanced equation, you can:
- calculate the moles of product produced if the moles of each reactant is known - calculate the mass of product formed from the mass of the reactants
anabolic pathways
build up
What is avogadro's number used for?
- used as a counting unit - conversion between moles and numbers of particles
1 calorie = 1 kcal = ?
1 x 10^3 calorie
Balance the equation using the lowest whole-number coefficients C12H22O11 + O2 --> CO2 + H2O
C12H22O11 + 12O2 --> 12CO2 + 11H2O
How many moles of Fe2O3 are in 183 g of the compound? number of moles: ??? mol
1.15 First, determine the molar mass of Fe2O3. There are 2 mol of Fe and 3 mol of O in 1 mol of Fe2O3. 2(55.847 g Fe / mol) + 3(15.999 g O / mol)=159.691 g/mol Use the molar mass to convert grams to moles. 183 g Fe2O3× (1 mol Fe2O3 / 159.691 g Fe2O3) =1.15 mol Fe2O3
A serving of soup contains 5.0 g, 12.0 g of carbohydrates, and 4.0 g of protein. Determine how many Calories (Cal) are contained in this serving. number of Calories: ??? Cal
109 Cal First, convert from the mass of fat, carbohydrates, and protein to kilocalories using the appropriate caloric conversion. carbohydrate = (4 Cal / g) fat = (9 Cal/g) protein = (4 Cal/g) carbohydrate = 12.0 g×(4 Cal / g)=48 Cal fat = 5.0 g × (9 Cal/g) = 45 Cal protein = 4.0 g×(4 Cal/g) = 16 Cal Calculate the total Calories by taking the sum of the Calories from each. total=48 Cal+45 Cal+16 Cal=109 Cal
The combustion of ethane (C2H6) produces carbon dioxide and steam. 2C2H6(g)+7O2(g)⟶4CO2(g)+6H2O(g) How many moles of CO2are produced when 5.50 mol of ethane is burned in an excess of oxygen? moles of CO2: ??? mol
11 From the balanced equation, the combustion of 2 mol C2H6 produces 4 mol CO2. Use this ratio as a conversion factor when calculating the number of moles of CO2 formed from the combustion of 5.50 mol C2H6. 5.50 mol C2H6 × (4 mol CO2 / 2 mol C2H6) = 11.0 mol CO2
Calculate the mass, in grams, of 0.487 mol of hydrogen peroxide, H2O2 mass of H2O2 = ??? g
16.6 When converting moles of a substance to grams, the conversion factor is the molar mass of the substance. The molar mass is numerically equal to the formula weight of the substance and has units of g/mol. For the second substance, H2O2H2O2, you need to calculate its formula weight. 2×1.0079 amu+2×15.999 amu=34.01 amu The molar mass of H2O2 is 34.013 g/mol. Use it as a conversion factor to calculate the mass of 0.487 mol H2O2. 0.487 mol×34.01 g/1 mol=16.6 g
How much does 1.00 mol of each substance weigh in grams? C6H12O6 (fructose) = ??? grams
180.15 The mass of 1 mol of a substance is the substance's molar mass and is equal to the substance's formula weight. (6×12.011 amu)+(12×1.0079 amu)+(6×15.999 amu)=180.16 amu
How many atoms are in 161 g of calcium? 161 g = ??? atoms
2.42 x 10^24 Convert grams to moles using the molar mass of calcium, 40.08 g/mol. Then, convert moles to atoms using Avogadro's number, 6.022×1023. 161 g Ca × (1 mol Ca / 40.08 g Ca) × (6.022×10^23 Ca atoms / 1 mol Ca) =2.42×10^24 Ca atoms
How many moles of boron, B, are in 1.63 x 10^24 B atoms? 1.63 x 10^24 B atoms = ??? mol
2.71 There are 6.022×10^23 atoms in 1 mole. To convert from atoms to moles, the conversion factor is 1 mol / 6.022×10^23 atoms Therefore, (1.63×10^24 atoms)(1 mol/6.022×1023 atoms)=2.71 mol
Balance the equation by inserting coefficients as needed KHF2 --> KH + H2 + F2
2KHF --> 2KF + H2 + F2
Determine the molar mass of Mn(ClO3)3 ??? g/mol
305.29 In a mole of Mn(ClO3)3, there is 11 mole of MnMn atoms, 33 moles of Cl atoms, and 3×3=9 moles of O atoms. Sum the masses of these components. The molar mass of each element can be found in the periodic table. 54.938 g/mol+3(35.453 g/mol)+9(15.999 g/mol) = 305.29 g/mol
The reaction for producing glucose in plants, called photosynthesis, is 6CO2+6H2O−→ C6H12O6+6O2 If a plant produces 5.81 mol C6H12O6, how many moles of H2O are needed? moles of H2O: ??? mol
34.9 To calculate the moles of H2O required to produce a certain number moles of C6H12O6, use the stoichiometric ratio between the two. From the balanced equation, the ratio is 6mol H2O / 1mol C6H12O6 Use the stoichiometric ratio to convert to moles of H2O. 5.81 mol C6H12O6 × (6 mol H2O / 1 mol C6H12O6) = 34.9 mol H2O
Consider a sample containing 0.730 mol of a substance. How many molecules are in the sample if the substance is benzene, C6H6? C6H6: ??? molecules
4.369 x 10^23 There are 6.022×1023 particles in 1 mol (Avogadro's number). It does not matter what kind of particles; it could be atoms, molecules, ions, or electrons, but 1 mol always contains the same number of particles. Use Avogadro's number as a conversion factor to convert from moles to atoms or molecules. 6.022 x 10^23 particles / 1 mol multiply by 0.730 mol
Consider a sample containing 0.730 mol of a substance. How many atoms are in the sample if the substance is copper? copper: ???? atoms
4.396 x 10^23 There are 6.022×1023 particles in 1 mol (Avogadro's number). It does not matter what kind of particles; it could be atoms, molecules, ions, or electrons, but 1 mol always contains the same number of particles. Use Avogadro's number as a conversion factor to convert from moles to atoms or molecules. 6.022 x 10^23 particles / 1 mol multiply by 0.730 mol
Consider a sample containing 0.730 mol of a substance. How many atoms are in the sample if the substance is platinum? platinum: ??? atoms
4.396 x 10^23 There are 6.022×1023 particles in 1 mol (Avogadro's number). It does not matter what kind of particles; it could be atoms, molecules, ions, or electrons, but 1 mol always contains the same number of particles. Use Avogadro's number as a conversion factor to convert from moles to atoms or molecules. 6.022 x 10^23 particles / 1 mol multiply by 0.730 mol
Molecular formula for Nicotine is C10H14N2. The Empirical formula is...
C5H7N
Calculate the mass, in grams, of 4.95 mol of krypton, Kr mass of Kr = ??? g
414 When converting moles of a substance to grams, the conversion factor is the molar mass of the substance. The molar mass is numerically equal to the formula weight of the substance and has units of g/mol. The atomic mass of KrKr is 83.8083.80 amu, and therefore its molar mass is 83.8083.80 g/mol. Use the molar mass as the conversion factor to calculate the mass in grams for the given number of moles. 4.95 mol × 83.80 g/1 mol=415 g
If you have 5 moles of ethanol, how many moles of oxygen? C2H6O + 3O2 --> 2CO2 + 3H2O
5.0 mole ethanol x 3 mol oxygen/1 mol ethanol = 15 mol oxygen
Calculate the maximum number of Calories (kilocalories) in a 2000‑ and a 2500‑Cal diet that should be obtained from fat. The daily values (DV) for fat and carbohydrates and the reference daily intake (RDI) for protein are given in the table. Fat, daily value for 2000-Cal diet is < 65 g Fat, daily value for 2500-Cal diet is < 80 g Calories from fat in a 2000-Cal diet: ??? Cal
585 Cal The units of the answer are in Calories (kilocalories). To get Calories, multiply Calories per gram by grams. (9 Cal/g) × 65 g = 590 Cal
Avogadro's number (1 mol)
6.02 x 10^23
To convert between moles and particles, use the conversion factor
6.02 x 10^23 = 1 mole
1 mol of formula unit =
6.02 x 10^23 formula unit
1 mol of molecules =
6.02 x 10^23 molecules
1 mol of atoms =
6.022 x 10^23 atoms
How much does 1.00 mole of each substance weigh in grams? SiO2 (silicon dioxide, quartz) = ??? grams
60.083 The mass of 1 mol of a substance is the substance's molar mass and is equal to the substance's formula weight. (1 x 28.086 amu) + (2 x 15.999 amu) = 60.08 amu
Calculate the maximum number of Calories (kilocalories) in a 2000‑ and a 2500‑Cal diet that should be obtained from fat. The daily values (DV) for fat and carbohydrates and the reference daily intake (RDI) for protein are given in the table. Fat, daily value for 2000-Cal diet is < 65 g Fat, daily value for 2500-Cal diet is < 80 g Calories from fat in a 2500-Cal diet: ??? Cal
720 Cal The units of the answer are in Calories (kilocalories). To get Calories, multiply Calories per gram by grams. (9 Cal/g) × 80 g = 720 Cal
One cup of whole chocolate milk contains 10 grams of fat, 8 grams of protein, and 25 grams of carbohydrates. How many Calories does it have? a. 220 Calories b. 43 Calories c. 172 Calories d. 387 Calories
A. 220 Calories
Label the reactants of the following chemical equation CH4 + 2O2 --> CO2 + 2H2O
CH4 and 2O2
Label the products of the following chemical equation CH4 + 2O2 --> CO2 + 2H2O
CO2 and 2H2O
A catalyst does not affect deltaH,
but lowers the activation energy (Ea)
Biochemical pathway
Biochemical reactions
Classify the chemical changes as endothermic or exothermic: - A chemical change takes place in a container, making it feel COLD to the touch - campers burn wood to stay warm at night - pocket hand warmers, often used by skiers, start out at room temperature. When the air-tight is opened, a substance contained in a cloth pouch reacts with air, and it quickly begins to feel hot - a "cold pack", often used for sports injuries, starts out at room temperature, but squishing the liquid around causes two substances to mix that were originally kept separate. When those substances react, the pack quickly begins to feel cold - A chemical change takes place in a container, making it feel HOT to the touch
ENDOTHERMIC: - A chemical change takes place in a container, making it feel COLD to the touch - a "cold pack", often used for sports injuries, starts out at room temperature, but squishing the liquid around causes two substances to mix that were originally kept separate. When those substances react, the pack quickly begins to feel cold EXOTHERMIC: - campers burn wood to stay warm at night - pocket hand warmers, often used by skiers, start out at room temperature. When the air-tight is opened, a substance contained in a cloth pouch reacts with air, and it quickly begins to feel hot - A chemical change takes place in a container, making it feel HOT to the touch
Balance the equation by inserting coefficients as needed P4O10 + 6H20 --> H3PO4
P4O10 + 6H2O --> 4H3PO4
The molar mass is the ____ as the molecular mass
SAME
A chemical equation is used to represent....
a chemical reaction. Reactants, on the left side of the arrow, and products, on the right side of the arrow, are represented by their chemical formulas or structures, separated by a reaction arrow. Whole-number coefficients are placed before each chemical formula to indicate the molar ratio of each reactant and product
Which of the reactions are exothermic? a. 2Mg(s)+O2(g)⟶2MgO(s)+heat b. NH3(g)+HCl(g)⟶NH4Cl(s)+heat c. AgCl(s)+heat⟶Ag+(aq)+Cl−(aq) d. 2Fe2O3(s)+3C(s)+heat⟶4Fe(s)+3CO2(g) e. C(graphite)+O2(g)⟶CO2(g)+heat f. CH4(g)+2O2(g)⟶CO2(g)+2H2O(l)+heat
a. 2Mg(s)+O2(g)⟶2MgO(s)+heat b. NH3(g)+HCl(g)⟶NH4Cl(s)+heat e. C(graphite)+O2(g)⟶CO2(g)+heat f. CH4(g)+2O2(g)⟶CO2(g)+2H2O(l)+heat
Which of the following is an example of equilibrium in biological systems? a. oxygen binding and unbinding hemoglobin b. bone growth in a small child c. acid indigestion caused by overproduction of gastric juices d. the eye tearing in response to a foreign object
a. oxygen binding and unbinding hemoglobin
an endothermic reaction
absorbs heat energy from the surroundings deltaH > 0 deltaH is positive because the products are higher in energy than the reactants
Le Chatelier's principle predicts that a reversible reaction at equilibrium will respond to a disturbance in such a way as to counteract the disturbance. Thus,
adding a reactant or removing a product will result in a shift to the right. Removing a reactant or adding a product will result in a shift to the left
as the temperature of a reaction increases, the rate of a reaction
also increases
in an energy diagram, the activation energy
appears as a hill connecting reactants to products. The higher the "hill" is, the greater the activation energy and the slower the reaction
A reversible reaction is a reaction in which the forward and reverse reaction
are occurring simultaneously
At equilibrium, the froward and reverse reactions proceed _____
at the same rate
The molecular mass of glucose C6H12O6 is: a. 342.3 g/mol b. 180.16 g/mol c. 44 g/mol d. 29.02 g/mol
b. 180.16 g/mol 12x6 1x12 16x6
For the reaction 2Na(s) + 2H2O(l0 --> 2NaOH(aq) +H2(g), if four moles of sodium react, how many moles of hydrogen gas are produced? a. 1 b. 2 c. 3 d. 4
b. 2
Which of the following equations is correctly balanced? a. Na(s) + 1/2Cl2(g) --> NaCl(s) b. 2Na(s) + Cl2(g) --> 2NaCl(s) c. 4Na(s) + 2Cl2(g) --> 3NaCl(s) d. 3Na(s) + 3/2Cl2(g) --> 3NaCl(s)
b. 2Na(s) + Cl2(g) --> 2NaCl(s)
Enzymes lower activation energies primarily by: a. increasing the temperature of the system b. forcing reactants into the correct spatial orientation to react c. adding kinetic energy to a system d. using ribosomes
b. forcing reactions into the correct spatial orientation to react
Consider the system at equilibrium. 2H2(g)+S2(g)↽−−⇀2H2S(g) How will adding a catalyst shift the equilibrium? a. to the left b. no effect c. to the right
b. no effect
The buffering system in the blood involves carbonic acid (H2CO3) and the bicarbonate ion (HCO−3). The reaction is H2CO3(aq)+H2O(l)↽−−⇀HCO−3(aq)+H3O+(aq) What will happen to the equilibrium if the amount of bicarbonate ion is increased? a. the equilibrium will not change. b. the equilibrium will shift to the left c. the equilibrium will shift to the right
b. the equilibrium will shift to the left
The buffering system in the blood involves carbonic acid (H2CO3) and the bicarbonate ion (HCO−3). The reaction is H2CO3(aq)+H2O(l)↽−−⇀HCO−3(aq)+H3O+(aq) What will happen to the equilibrium if the concentration of carbonic acid is increased? a. the equilibrium will not change. b. the equilibrium will shift to the right c. the equilibrium will shift to the left
b. the equilibrium will shift to the right
Consider the system at equilibrium. 2H2(g)+S2(g)↽−−⇀2H2S(g) How will increasing the concentration of S2 shift the equilibrium? a. to the left b. to the right c. no effect
b. to the right
Given the following equation, identify the correct result when the equilibrium is disturbed: CH3CH2COOH + H2O --> CH3CH2CH2COO- + H3O+ a. When butanoate ions are added, the reaction shifts to the right b. when water is added, the reaction moves to the right c. when butanoic acid is added, the reaction shifts to the left d. when water is removed, the reaction moves to the right
b. when water is added, the reaction moves to the right
What is the mass of 2 moles of carbon? a. 12.01 g b. 12 g c. 24.02 g d. 6.05 g
c. 24.02 g 6.02 x 12
Caroline knows the amount of a compound in moles. To find the number of molecules in the given sample of her compound, which of these values must also be used in the calculation? a. molecular mass of the compound b. mass of the sample in grams c. Avogadro's number d. atomic mass of each element in the compound
c. Avogadro's number
Reactions can absorb or release heat energy. If a reaction releases energy as it progresses, it is said to be a. endothermic b. enthalpic c. exothermic d. entropic
c. exothermic
Increasing the concentration of a reactant in a mixture will have what effect on the reaction rate? a. It will decrease the rate b. it will have no effect c. it will increase the rate d. it cannot be determined
c. it will increase the rate
Which definition best describes the term activation energy? a. the energy required to separate ions in a crystalline solid b. the energy of motion c. the minimum kinetic energy that particles must possess for a chemical reaction to occur d. the energy required to remove an electron from a gaseous atom
c. the minimum kinetic energy that particles must possess for a chemical reaction to occur
Consider the system at equilibrium. 2H2(g)+S2(g)↽−−⇀2H2S(g) How will increasing the concentration of H2S shift the equilibrium? a. to the right b. no effect c. to the left
c. to the left
The caloric content of foods (the heat released during their combustion) has been determined by
calorimetry. Carbohydrates and proteins release approximately 4 Cal/g, whereas fats release 9 Cal/g
metabolism consists of two types of metabolic pathways
catabolic and anabolic. Catabolic pathways convert large molecules into smaller molecules, whereas anabolic pathways convert small molecules into larger ones. Catabolic pathways release energy, whereas anabolic pathways absorb energy overall
The difference in potential energy between the reactants and products can be measured. The difference is the
change in enthalpy
In biochemical reactions, energy is not transferred as heat; instead it is transferred in the form of
chemical energy to and from specialized energy-carrier molecules, such as adenosine triphosphate (ATP)
Stoichiometry calculations
coefficients are the molar ratio of the reactants and products
the rate of an enzyme catalyzed reaction is affected by
concentration, temperature, and the presence of a catalyst
the three major factors that affect the rate of reaction are
concentration, temperature, and whether or not a catalyst is present
The concentration of reactants and products in equilibrium reactions are ____
constant
Balance the reaction H2+O2 --> H20 a. H2 + O2 --> H2O b. H2 + O --? H2O c. H2 + 1/2O2 --> H2O d. 2H2 + O2 --> 2H2O
d. 2H2 + O2 --> 2H2O
The combination of oxygen with a hydrocarbon to form carbon dioxide and water is a combustion reaction. Write and balance the equation for the combustion of pentane. a. C5H12 + O2 --> CO2 + H2O b. C5H12(l) + O2(g) --> CO2(g) + H2O(l) c. 2C5H10(l) + 13O2(g) --> 8CO2(g) + 10H2O(l) d. C6H12(l) + 8 O2(g) --> 5CO2(g) + 6H2O(l)
d. C5H12(l) + 8O2(g) --> 5CO2(g) + 6H2O(l)
The rate of a reaction usually decreases as the concentration of reactants
decreases
the rate of a reaction _______ as the concentration of reactions _______
decreases, decreases
First Law of Thermodynamics
energy is neither created nor destroyed, only transformed
Calorimetry is used to measure
enthalpy changes, using a calorimeter
Biological catalysts are called
enzymes. Almost all biochemical reactions require an enzyme
at equilibrium, the rate of the forward reaction is
equal to the rate of the reverse reaction; therefore, the concentration of reactants and products is constant at equilibrium
Formula mass is calculated
from the mass of the individual ions that make up the formula unit of the ionic compound
molecular mass is calculated
from the sum of the atomic masses of the component atoms in the molecule
molar mass is in ______, molecular mass is in _______
g/mol .... amu
a mole-to-mole stoichiometry calculation can be preformed
given a balanced equation. In a mole-to-mole stoichiometry calculation, we can determine the number of moles of any reactant or product given the moles of any other reactant or product
calorie from carbohydrate
grams of carbohydrate x 4 Cal/g
calorie from fat
grams of fat x 9Cal/g
calorie from protein
grams of protein x 4 Cal/g
most chemical reactions absorb or releases
heat
Endothermic reaction
heat is absorbed, deltaHreaction > 0
Exothermic reaction
heat is released; deltaHreaction < 0
Kinetics
how fast a reaction proceeds
Enzymes
increase reactions rates in cells
a catalyst is not a reactant because
it is chemically unchanged during a reaction. Instead, a catalyst facilitates the reaction, often by bringing the reactants together in the proper orientation
if products are added, the reaction will shift to the ...
left - more reactants will be produced
If reactants are removed, the reaction will shift to the ...
left - more reactants will be products
a catalyst increases the rate of a reaction by
lowering the activation energy of the reaction
A catalyst (enzymes) _______ lowers the activation energy of the reaction
lowers
the activation energy, Ea is the
minimum amount of energy that must be attainted by the reactants for a chemical reaction to occur
Coefficients indicate the...
molar ratio of the reactants and products
the energy transferred in a chemical reaction
often appears in the form of heat
chemical bonds have
potential energy. Carbohydrates, proteins, and fats are the important food molecules with high potential energy in their covalent bonds
Le Chatelier's principle
predicts that a reaction at equilibrium will respond to a disturbance to establish a new equilibrium
Chemical reactions include _____ and _____
reactants and products
Automobile airbags inflate due to the formation of nitrogen gas from the chemical reaction 2NaN3(s)⟶3N2(g)+2Na(s) Identify the number of Na atoms in the reactants and products. reactants: ??? Na atoms products: ??? Na atoms
reactants: 2 Na atoms products: 2 Na atoms
Automobile airbags inflate due to the formation of nitrogen gas from the chemical reaction 2NaN3(s)⟶3N2(g)+2Na(s) Identify the number of Na atoms in the reactants and products. reactants: ??? N atoms products: ??? N atoms
reactants: 6 N atoms products: 6 N atoms
Chemical kinetics is the study of
reaction rates - how fast reactants are converted into products
An exothermic reaction
releases heat into the surroundings deltaH > 0 delta H is negative because the products are lower in energy than the reactants
If products are removed, the reaction will shift to the....
right - more products will be produced
If reactants are added, the reaction will shift to the ...
right - more products will be produced
Exothermic reactions will shift to the left with added heat, whereas endothermic reactions will
shift to the right. Conversely, exothermic reactions will shift to the right when heat is removed, whereas endothermic reaction will shift to the left
Metabolism =
sum of biochemical pathways
Molecular mass
sum of the masses of its component atoms
balancing a chemical reaction requires
systematically inserting whole-number coefficients in front of the reactants and/or products so that the number of each type of atom is the same on the reactant side as on the product side
Calorimetry is a
technique used to measure enthalpy changes, deltaH, using an apparatus called a calorimeter
the energy for a reaction to occur is
the activation energy Ea
Energy is
the capacity to do work or transfer heat
an energy diagram illustrates
the change in energy during a chemical reaction the x-axis represents the reaction progress and the y-axis represents energy
In a balanced chemical reaction,
the total number of each type of atom on the reactant side must equal the total number of each type of atom on the product side
the addition of a catalyst to a reaction lowers the activation energy
thereby increasing the rate of the reaction
the activation energy is proportional
to the rate of the reaction
To interconvert between mass and number of particles...
use both molar mass and Avogadro's number as conversion factors
To convert between moles and mass....
use dimensional analysis, with the molecular mass as a conversion factor
To interconvert between moles and mass...
use molar mass (or inverted molar mass) as a conversion factor