CHEM 120 Exam 3 Latest Update 2025-2026
Exam Questions with 100% Verified Correct
Answers Guaranteed A+
A catalyst is distinguished by - CORRECT ANSWER: having the same amount present
at the end of the reaction as there was before the reaction
Avogadro's number is the number of - CORRECT ANSWER: particles in one mole of a
substance
Exothermic reactions - CORRECT ANSWER: release heat
Heptane is always composed of 84% carbon and 16% hydrogen. Which law does this
illustrate? - CORRECT ANSWER: Law of Definite Proportions
How does Dalton's atomic theory explain that compounds always have the same mass
ratio of elements (such as silver sulfide always being 7 parts silver and 1 part sulfide by
weight) - CORRECT ANSWER: Compounds are formed by atoms combining in fixed
proportions.
How many atoms of C are in 1 mole of CO2 - CORRECT ANSWER: 6.02 x 1023
How many moles are in 480 g of CaCl2? The molar mass of CaCl2 is 111.16 g/mol. -
CORRECT ANSWER: 4.3 moles
In the following balanced reaction: CH3CH2OH + 3 O2 --> 2 CO2 + 3 H2O how many H
atoms are in the products? - CORRECT ANSWER: 6
Exam Questions with 100% Verified Correct
Answers Guaranteed A+
A catalyst is distinguished by - CORRECT ANSWER: having the same amount present
at the end of the reaction as there was before the reaction
Avogadro's number is the number of - CORRECT ANSWER: particles in one mole of a
substance
Exothermic reactions - CORRECT ANSWER: release heat
Heptane is always composed of 84% carbon and 16% hydrogen. Which law does this
illustrate? - CORRECT ANSWER: Law of Definite Proportions
How does Dalton's atomic theory explain that compounds always have the same mass
ratio of elements (such as silver sulfide always being 7 parts silver and 1 part sulfide by
weight) - CORRECT ANSWER: Compounds are formed by atoms combining in fixed
proportions.
How many atoms of C are in 1 mole of CO2 - CORRECT ANSWER: 6.02 x 1023
How many moles are in 480 g of CaCl2? The molar mass of CaCl2 is 111.16 g/mol. -
CORRECT ANSWER: 4.3 moles
In the following balanced reaction: CH3CH2OH + 3 O2 --> 2 CO2 + 3 H2O how many H
atoms are in the products? - CORRECT ANSWER: 6
