Chemical Reactions

Which statement provides evidence that mass is conserved in the reaction?

• Two new substances are formed in the products

• Water is one of the products, but not one of the reactants

• Two hydrogen atoms are in the reactants and two hydrogen atoms are in the products

• One chlorine atom pairs with one sodium atom in the products and one chlorine atom pairs with one hydrogen atom in the reactants.

Tags

NGSS.MS-PS1-5

Samara put a quantity of sulfur, a yellow powder, into a test tube. She gently heated the tube and observed that the powder turned black. What happened?

• The sulfur underwent a physical change called melting.

• The sulfur underwent a chemical change called burning.

• The sulfur underwent a chemical change called melting.

• The sulfur underwent a physical change called burning.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A chemical reaction in which calcium carbonate, CaCO₃, is decomposed results in the production of two simpler compounds. CaO (? g) + CO₂ (21.97 g) ₌ CaCO₃ (28.00 g) What is the mass of calcium oxide if it follows the Law of Conservation of Mass?

Tags

NGSS.MS-PS1-5

In which investigation is it least likely that the liquids reacted chemically?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

In an endothermic reaction, heat is ...

• taken in or absorbed

• given out or released 

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

When does a chemical reaction stop?

• When the lab is finished

• When the excess reactant is used up

• When the limiting reactant is used up

• Chemical reactions never stop

Tags

NGSS.MS-PS1-5

Which of the following shows the correct way to balance the chemical equation?
Fe + O₂ -> Fe₂O₃

• 4Fe + 3O₂ -> 2Fe₂O₃

• 2 Fe + 3O₂ -> Fe₂O₆

• 4 Fe + O₆ -> 2Fe₂O₃

• None of the options are correctly balanced.

Tags

NGSS.MS-PS1-5

Balance this equation...
HgO --> Hg + O₂

• It is balanced 

• 2HgO --> Hg + O₂

• 2HgO --> 2Hg + O₂

• I don't know...Oh well!

Tags

NGSS.MS-PS1-5

What happens in ALL chemical changes?

• Change in state of matter

• A new substance is formed

• Bubbles are produced

• An explosion

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

According to the law of conservation of mass, how does the amount of each element on the product side compare to each element on the reactant side?

• The amount of atoms on each side is equal

• The amount of atoms on the product side is greater

• The amount of atoms on the reactant side is greater

• Depends on the reaction

Tags

NGSS.MS-PS1-5