Intro to Chemical Rxns
Conservation of Mass
Stoichiometry (mole to mole calcs)
Types of Chemical Reactions
Mole Unit Review
100
Which statement describes a chemical change?
(1) Alcohol evaporates
(2) Water vapor forms snowflakes
(3) Table salt (NaCl) is crushed into powder
(4) Glucose and oxygen produce CO2 and H20
(4) Glucose and oxygen produce CO2 and H20
100
Given the balanced equation representing a reaction:
NH3(g) + O2(g) →N2(g) + H2O(g) + energy
What mass of ammonia completely reacts with 15g of oxygen to produce 32 g of nitrogen and 40g of water?
57g
100
The coefficients in a balanced chemical equation represent
(l ) the mass ratios of the substances in the reaction
(2) the mole ratios of the substances in the reaction
(3) the total number of electrons in the reaction
(4) the total number of elements in the reaction
(2) the mole ratios of the substances in the reaction
100
Given the balanced equations representing two chemical reactions:
2 NaBr → 2 Na + Br2
AgNO3 + NaCl → NaNO3 + AgCl
Which types of chemical reactions are represented by these equations?
(1) single replacement and decomposition
(2) single replacement and double replacement
(3) synthesis and decomposition
(4) decomposition and double replacement
(4) decomposition and double replacement
100
Show a numerical setup for calculating the percent composition by mass of oxygen in Al2O3 (gram-formula mass = 102 g/mol).
(54/102) x 100
200
For the following reaction, state whether it is exothermic or endothermic AND state evidence from the equation:
S(s) + O2(g) --> SO2(g) + energy
Exothermic because energy is on the right OR because energy is being released
200
Finish balancing the following equation using the smallest whole-number coefficients:
2Sb2S3(s) + O2(g) → Sb2O3(s) + SO2(g)
2Sb2S3(s) + 9O2(g) → 2Sb2O3(s) + 6SO2(g)
200
The balanced equation below represents the reaction between carbon monoxide and oxygen to produce carbon dioxide.
Determine the number of moles of O2(g) needed to completely react with 8.0 moles of CO(g).
4 moles
200
Given the balanced equation representing a reaction:
2H2 + O2 → 2H2O + energy
Which type of reaction is represented by this equation?
Synthesis
200
Vitamin C, also known as ascorbic acid, has a molecular formula of C6H8O6 and a gram-formula mass of 176 grams per mole.
Determine the number of moles of vitamin C in an orange that contains 0.071 gram of vitamin C.
4.03x10-4 or 0.000403 moles
300
What three things must be conserved during a chemical reaction?
mass, energy, and charge
300
What is the missing product in the following equation? Pb(NO3)2 + 2NaI --> PbI2 + 2______
1) Na2O
2) Na2NO3
3) NaNO3
4) Na2(NO3)2
3) NaNO3
300
What is the mole-to-mole ratio between Al and Al2O3 in the following balanced equation?
8 Al + 3 Fe3O4 ---> 4 Al2O3 + 9 Fe ?
2:1
300
What is the name of the group that contains nonmetals that are most likely to undergo a chemical reaction?
Halogens
300
What is the chemical formula for ammonium sulfide?
(NH4)2S
400
Which balanced equation represents a chemical change?
(1) H2O(l) + energy → H2O(g)
(2) 2H2O(l) + energy → 2H2(g) + O2(g)
(3) H2O(l) → H2O(s) + energy
(4) H2O(g) → H2O(l) + energy
(2) 2H2O(l) + energy → 2H2(g) + O2(g)
400
Explain why the balanced equation below represents a conservation of atoms.
6Li + N2 → 2Li3N
Same # of atoms of each element on both sides of the equation
400
Given the equation: CH4 + 2O2 --> CO2 + 2H2O
How many moles of oxygen are needed for the complete combustion of 3.0 moles of methane?
6 moles
400
The equation below is best classified as which type of chemical reaction?
2C2H2 + 7O2 --> 4CO2 + 6H2O
Combustion
400
Determine the molecular formula for a compound that has the empirical formula CH2O and a molar mass of 120. grams per mole.
C4H8O4
500
When an exothermic reaction occurs in a water solution, the temperature of the solution
a)Increases because energy is given off by the reaction
b)Increases because energy is absorbed by the reaction
c)Decreases because energy is given off by the reaction
d)Decreases because energy is absorbed by the reaction
a)Increases because energy is given off by the reaction
500
Given the unbalanced equation: Ca(OH)2 + (NH4)2SO4 ---> CaSO4 + NH3 +H2O.
What is the sum of the coefficients when the equation is completely balanced using the smallest whole-number coefficients?
5. When
7
500
Given the reaction: 2C2H2(g) + 5O2(g) --> 4CO2(g) + 2H2O(g), what is the total number of grams of O2(g) needed to react completely with 13 grams of C2H2(g)?
40 grams of O2(g)
500
For the following reaction, identify the type and state why.
2NaHCO3 + heat --> Na2CO3 + H2O + CO2
Decomposition because one reactant is breaking down into several products
500
What is the empirical formula of a compound that contains 85% Ag and 15% F by mass?
AgF