Spring 22 Final Review

Matter can not be created nor destroyed: it can only be

• Destroyed a little bit
• Invisible
• Transformed, changed
• None of the above

The number in front of a compound or element is a 

• Subscript
• Coefficient
• Superscript
• Charge

A chemical reaction is balanced when

• both sides have the same elements
• Both sides have the same  number of atoms
• Same subscripts
• Same coefficients

The coefficient in  3H₂O is

• 6
• 2
• 3
• 5

If reaction starts with 20g of reactants it should produce 

• a total of 40g of products
• a total of 10g of products
• a total of 80 g of products
• a total of 20g of products

Measure of the amount of matter 

• mass
• volume
• weight
• density

What is the Law of Conservation of mass?

• Mass is created in a chemical reaction
• Mass is created in a physical change
• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
• Mass is never created or destroyed

2 KClO₃ → 2 KCl + 3 O₂
How many moles of oxygen are produced when 6.7 moles of KClO₃ decompose completely?

• 6.7 mol
• 1.0 mol
• 10.1 mol
• 4.5 mol

2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

• 5.2 g
• 2.6 g
• 690 g
• 45 g

Using the following equation:
Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l)
How many moles of iron (Fe) can be made from  6 moles H₂? 

• 4 moles Fe
• 6 moles Fe
• 9 moles Fe
• 2 moles Fe