test

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

What are the REACTANTS :

H₂O + CO₂ → HCO + HO

• H₂O + CO₂

• HCO + HO

• H₂O ONLY

• HCO ONLY

Does this follow the law of conservation of mass:

Yes No

2Fe₂O₃ + 3C --> 4Fe + 3 CO₂

• Yes

• No

Does this follow the law of conservation of mass:

Yes No

Al + O₂ → 2Al₂O₃

• Yes

• No

How many Elements are in the compound C₂H₈O ?

• 2
• 1
• 3
• 0

The number of Na's in Na₂CO₃

• 1
• 2
• 3
• 6

Number of C's in 2Na₂CO₃

• 1
• 2
• 3
• 5

How many Sodium (Na) are in 6NaCl?

• 1
• 12
• 6

What are the REACTANTS :

H₂O + CO₂ → HCO + HO

• H₂O + CO₂

• HCO + HO

• H₂O ONLY

• HCO ONLY