Chemical Reactions Unit Exam

Which law tells us that the sum of the masses of individual elements is equal to the mass of the entire compound?

• Law of Conversation of Energy

• Law of Conservation of Mass

• Law of Conservation of Matter

• Law of Conversation of Momentum

Tags

NGSS.HS-PS1-7

Avogadro's number, or 6.022 x 10²³ is...

• the atomic mass of a compound

• number of particles in one gram of a substance

• number of particles in one mole of a substance

• number of particles in the total mass of a substance

Which of the following can be used to define molar mass?

• the mass in grams of one mole of a substance (g/mol)

• can be found by adding the average atomic masses of all atoms in a compound

• can be found using Avogadro's number

• the mass in grams of a single substance

How many moles are in 9.0 grams of C?

• 0.50

• 7.50

• 0.75

• 0.750

How many moles are in 32.0 grams of SO₂?

• 0.500

• 0.50

• 0.499

• 0.49

How do you know when a chemical equation is balanced?

• There are the same coefficients in both the reactants and products

• Subscripts of reactants are the same as the subscripts of the products

• The same amount (or number) of each kind of atom appears on both sides

• The coefficients add up to the same numbers on both sides

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Balance the following: Fe₂O₃ + C --> Fe + CO₂

• 2Fe₂O₃ + C --> 4Fe + CO₂

• 3Fe₂O₃ +3 C --> 6Fe + CO₂

• 2Fe₂O₃ + 3C --> Fe + 3CO₂

• 2Fe₂O₃ + 3C --> 4Fe + 3CO₂

Tags

NGSS.HS-PS1-7

What time of chemical reaction is in this unbalanced equation: Fe₂O₃ + C --> Fe + CO₂?

• Single replacement

• Double replacement

• Combustion

• Combination/Synthesis

What are the coefficients needed to balance this equation:

N₂ + H₂ --> NH₃ ?

• 2,3,2

• 1,3,2

• 1,3,1

• 2,3,1

What type of chemical reaction is this equation: N₂ + H₂ --> NH₃

• single replacement

• double replacement

• decomposition

• combination/synthesis