Chemistry, Chapter 7: Chemical Reactions and Quantities

The mass of 1 mole of a substance, the atomic mass expressed in grams.

Molar mass

The amount that contains as many elementary entities as there are atoms in exactly 12 grams of C-12.

Mole

How many moles of Fe2O3 can form from 6.0 moles of O2? 4Fe(s) + 3O2(g) -> 2Fe2O3(s)

4.0 mol Fe2O3

What are the coefficients needed for C3H8 (g) + O2 (g) -> CO2 (g) +H2O (g)?

1, 5, 3, 4

What are the coefficients needed for C10H16 + Cl2 -> C + HCl?

1, 8, 10, 16

The number of atoms of 2.0 moles of Al is what?

1.2x10^24 atoms

Find the formula weight of Na2CO3 (may be off by a few depending on your periodic table).

105.99 amu

The reaction between H2 and O2 produces 13.1 g of water. How many grams of O2 reacted? 2H2(g) + O2(g) ->2H2O(g)

11.6 g O2

A box of table salt, NaCl, contains 737 g of NaCl. How many moles of NaCl are in the box?

12.6 mol NaCl

How many grams of O2 are needed to produce 45.8 grams of Fe2O3 in the following reaction? 4Fe(s) + 3O2(g) -> 2Fe2O3(s)

13.8 g O2

How much heat in kJ is released when nitrogen and hydrogen react to form 50.0 g of ammonia? N2(g) + 3H2(g) -> 2NH3(g) delta heat = -92.2 jK

135 kJ

How many moles of Fe are needed for the reaction of 12.0 moles of O2? 4Fe(s) + 3O2(g) -> 2Fe2O3(s)

16.0 mol Fe

What are the coefficients needed for Al(s) + S(s) -> Al2S3

2, 3, 1

What are the coefficients needed for Na3PO4 (aq) + MgCl2 (aq) -> Mg3(PO4)2 (s) -> NaCl (aq)

2, 3, 1, 6

If 3.00 moles of CO and 5.00 moles of H2 are the inital reactants, how many moles of methanol (CH3OH) can be produced and what is the limiting reactant? CO(g) + 2H2(g) -> CH3OH(g)

2.50 mol of methanol, LR = H2

Methanol burns in air according to the equation: 2CH3OH + 3O2 -> 2CO2 + 4H2O If 209 g of methanol are used up in the combustion, what mass of water is produced?

235 grams H2O

The number of moles of S in 1.8x10^24 atoms of S is what?

3.0 mol S

Avogadro's number is used to convert moles of a substance to particles. How many CO2 molecules are in 0.500 mole of CO2?

3.01x10^23 molecules CO2

Given the following reaction, N2(g) + 3H2(g) -> 2NH3(g) calculate the amount of ammonia, NH3, that can be formed when 2.50 grams of nitrogen gas, N2, reacts with 2.00 grams of hydrogen gas, H2.

3.04 g NH3, LR = NH3

How any O atoms are in 0.150 mole of aspirin, C9H8O4?

3.61X10^23 atoms O

Suppose we want to determine the mass (in grams) of NH3 that can be produced from 32 grams of N2 in the following equation: N2(g) + 3H2 (g) -> 2NH3(g)

39 grams NH3

What are the coefficients needed for C2H5 + O2 -> H2O + CO2?

4, 13, 10, 8

How many molecules are in 0.24 g of CH3OH?

4.5x10^21 molecules CH3OH

When N2 and 5.00 g of H2 are mixed, the reaction produces 16.0 g of NH3. What is the percent yield for the reaction?

56.8%

What does one mole equal?

6.02x10^23

Silicon carbide, SiC, is a ceramic material that tolerates extreme temperatures and is used as an abrasive and in the brake discs of sport cars. How many grams of CO are formed from 70.0 g of SiO2 and 50.0 grams of C? SiO2(s) + 3C(s) -> SiC(s) + 2CO(g)

65.3 g CO, LR = SiO2

What's the molar mass of Li2CO3? (may be off by a few depending on your periodic table)

73.89 g

The number of each type of atom in the reactant is equal to the number of each atom in the product.

A balanced chemical equation

The mass of product formed in a chemical (the number recorded in a laboratory)

Actual yield

Balance the equation for the combustion of C3H8.

C3H8 + 5O2 -> 3CO2 + 4H2O

Chemical changes can be recognized by what three things?

Change in color, formation of bubbles, and produce or absorb heat

This reaction occurs when two or more reactants combine to form a product.

Combination reaction

This reaction occurs when a carbon containing compound burns in oxygen from the air to produce CO2, H2O, and energy (heat).

Combustion reaction

When calculating heat changes, mole ratios and heat can be written as ______ _____

Conversion factors

Moles of Elements in a Formula: -Subscripts are used to write _____ _____ for moles of each element in 1 mole of a compound. -Fr 1 mole of asprin, C9H8O4, the possible conversion factors are what?

Conversion factors, 1 mol aspirin/9 mol C, 1 mol aspirin/8 mole H, 1 mole aspirin/4 mol O

In Law of Conservation of Mass indicates that in an ordinary chemical reaction, -Matter cannot be ______ or ______. -The total mass of reactants _____ total mass products.

Created, destroyed, equal

Given the following equation Cu(s) + 2AgNO3(aq) -> Cu(NO3)2(aq) -> 2Ag(s) Give the half equations by determining what's being oxidized and/or being reduced. Then give the overall reaction is written as what?

Cu is being oxidized, Ag is being reduced. Cu^0 + 2Ag^+ -> Cu^2+ + 2Ag^0

This reaction occurs when a substance splits into two or more products.

Decomposition reaction

This reaction occurs when the substance in the reactants change partners.

Double replacement reaction

Heat is absorbed.

Endothermic reaction

The reactant that does not completely react and is left over at the end of the reaction is called the what?

Excess reactant

Heat is released.

Exothermic reaction

Balance the chemical equation when solid Fe3O4 reacts with hydrogen gas to produce solid iron and water.

Fe3O4(s) + 4H2 (g) -> 3Fe (s) + 4H2O (l)

The sum of all the atomic masses in atomic mass units (amu) of all the atoms in a compound formula.

Formula weight (FW)

In an endothermic reaction, the energy of the products is _____ than the energy of the reactants. Heat is a _____

Greater, reactant

In an exothermic reaction, the energy of the products is _____ than the energy of the reactants. Heat is considered a _____

Less, product

Is a substance that gets used up first, limits how much product you can produce.

Limiting reactant

What's the first thing you do when you see an equation?

Make sure it's balanced

Is a rate of the moles (from the coefficients in the balanced chemical equation) for any two substances in an equation.

Mole-mole factor

Should only be used for molecular compounds

Molecular weight (MW)

Formula weight: -Can be used for ______ and ______ compounds. -It tells nothing about ______ _____

Molecular, ionic, bonding type

Is losing electrons

Oxidation

In biological systems, oxidation and reduction may involve what?

Oxidation may involve the loss of H or gaining of oxygen. Reduction may involve the gain of H or losing oxygen.

Any reaction in which any electrons are transferred from one species to another.

Oxidation-reduction (redox) reaction

How do you write a chemical equation?

Reactants are on the left and the products are on the right, separated by an arrow. If there are more than one products and/or reactants, they're separated by + signs.

During a chemical reaction -atoms are _____ -one or more new substances _____ -new _____ and _____ properties

Rearranged, formed, physical, chemical

Is gaining electrons

Reduction

This reaction occurs when a substance replaces one element in a compound.

Single replacement reaction

Study of mass relationships within a chemical reaction

Stoichiometry

The amount of heat absorbed or released during a reactant that takes place at constant pressure. The change in energy occurs when reactant interact, bonds break apart, and when produces are formed.

The heat of reaction

Is the difference between the enthalpy of the products and enthalpy of the reactants.

The heat of reaction or enthalpy change

The mass of a product that should form based on stiochiometry

Theoretical yield

On a space shuttle, LiOH is used to absorb exhaled CO2 from breathing air to form LIHCO3. What is the percent yield of the reaction of 50.0 g of LiOH gives 72.8 g of LiHCO3? LiOH(s) + CO2(g) -> LiHCO3(s)

Theoretical yield is 141.87 g LiHCO3 and the percent yield is 51.3%

Given the follow equation CuSO4(aq) + Zn (s) -> Cu(s) + ZnSO4(aq) Give the half equation by determining what's being oxidized and/or reduced. Then give the overall reaction is written as what?

Zn is being oxidized, Cu is being reduced. Zn^0 + Cu^2+ -> Zn^2+ + Cu^0

What is the formula for percent yield?

actual yield/theoretical yield x 100

What's the equation for enthalpy change?

change in heat = heat of products - heat of reactants

Identify each of the following reactions as a combination, a decomposition, a single replacement, a double replacement, or a combustion reaction. 1.) 3Ba (s) + N2 (g) -> Ba3N2 (s) 2.) Hg (l) + 2HCl (aq) -> HgCl2 (aq) + H2 (g) 3.) PbCl2 (aq) + K2SO4 (aq) -> 2KCl (aq) + PbSO4 (s) 4.) K2CO3 (s) -> K2O (s) + CO2 (g) 5.) CH4 (g) + 2O2 (g) -> CO2 (g) + 2H2O (g) + energy

combination, single replacement, double replacement, decomposition, combustion

In chemical equations, Triangle = S = l = g = aq =

heat is needed to start reaction, solid, liquid, gas, and aqueous