Chemistry review

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

In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B should have? 

• 4g
• 5g
• 9g
• 14g

In the reaction AB-----> A + B reactant AB has 12g and product B has 5g. How many grams should product A have?

• 17g
• 2g
• 7g
• None of the above

A chemical reaction is balanced when

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

Which of these is not a chemical reaction?

• Burning of wood
• Milk going bad
• Mixing vinegar and baking soda
• Melting of ice

24 g of magnesium reacts with 38 g of fluorine to produce _____ g magnesium fluoride

• 62 
• 38
• 24
• 14

A substance that contains only one type of atom is a(n)

• compound
• element
• heterogeneous mixture
• homogeneous mixture

Contains two or more atoms combined

• Elements
• Compounds
• Mixtures

Examples are milk and gasoline.

• elements
• mixtures
• compounds

Examples are diamonds (C) and Uranium (U)

• elements

• mixtures

• compounds