Law of Conversation of Mass

In a chemical reaction the total mass of the reactant

• exactly equal to the total mass of the product

• unrelated to the total mass of the product

• less than the total mass of the product

• greater than the total mass of the product

Tags

NGSS.MS-PS1-5

The best evidence for a chemical reaction is

• a change in color

• the formation of a new substance

• the production of a gas

• the production of a solid

Tags

NGSS.MS-PS1-2

The law of conservation of mass states

• during a chemical reaction, matter is created and destroyed

• during a chemical reaction, matter is created

• during a chemical reaction, matter is neither created nor destroyed

• during a chemical reaction, matter is destroyed

Tags

NGSS.MS-PS1-5

Sara adds 10g of baking soda to 100g of vinegar. The mixture begins to bubble. When the bubbling stops, Sara finds the mass of the resulting mixture. She determines the mass to be 105g. Why has the mass changed?

• vinegar evaporated during the experiment

• a gas formed and left the mixture

• mass was destroyed when the vinegar was added

• the production of a new gas

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

A solid magnesium, Mg, reacts with oxygen gas, O₂. Which equation is a balanced chemical equation for this chemical change?

• 2Mg+O------> Mg+O₂

• Mg+O₂---------->MgO₂

• MgO------>Mg2O

• 2Mg_{2 +}O--------->MgO₂

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

NGSS.MS-PS1-2

The starting materials in a chemical reaction

• Reactants

• Products

• Subscript

• Chemical Equation

Tags

NGSS.MS-PS1-5

What is the ending material in a chemical equation?

• reactant

• product

• chemical equation

• subscript

Tags

NGSS.MS-PS1-5

The balanced chemical equation below shows water breaking down (decomposing) into hydrogen and oxygen gas. How many atoms are in the reactants?

2H₂O ----------> O_{2 +} 2H₂

• 4

• 6

• 8

• 2

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

NGSS.MS-PS1-2

The balanced chemical equation below shows water breaking down (decomposing) into hydrogen and oxygen gas. How many atoms are in the product?

2H₂O ----------> O_{2 +} 2H₂

• 2

• 6

• 4

• 8

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

The balanced chemical equation below shows water breaking down (decomposing) into hydrogen and oxygen gas. How many hydrogen atoms are in the reactants?

2H₂O ----------> O_{2 +} 2H₂

• 2

• 4

• 6

• 8

Tags

NGSS.MS-PS1-1