Chemical Formulas, Reactions, Naming, Law of Conservation of Mass

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

Tags

NGSS.HS-PS1-7

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

Tags

NGSS.HS-PS1-7

The number in front of a compound or element is a 

• Subscript
• Coefficient
• Superscript
• Charge

The number to the lower side of an element is a 

• Subscript
• Superscript
• Coefficient
• Charge

Tags

NGSS.MS-PS1-1

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

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

Tags

NGSS.HS-PS1-7

Which is Chemical Equation is Balanced?

• CH₄+O₂------CO₂+2H₂O
• H₂+O₂-----2H₂O₄
• 4Al+3O₂-----2Al₂O₃

Tags

NGSS.MS-PS1-5

Is this equation balanced or unbalanced? 
2Fe₂O₃ + 3C --> 4Fe + 3 CO₂

• balanced
• unbalanced

Tags

NGSS.HS-PS1-7

If a reaction starts with a total 75g of reactants it should produce 

• a total of 40g of products
• a total of 75g of products
• a total of 180 g of products
• None of the above

Tags

NGSS.HS-PS1-7

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

Tags

NGSS.HS-PS1-7

Which of the following is the best description of the results of a chemical reaction?

• The substance seems to disappear after dissolving in water.
• The substance changes from liquid to solid at a low temperature.
• The reaction can be reversed to get back the original substance.
• A new substance with different properties is formed.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5