Chemical reactions and equations

Which of the following would indicate that a chemical reaction has occurred?

• A new element has been created

• A different substance has formed

• The total mass has either increased OR decreased

• The total number of elements has either increased OR decreased

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

In a chemical reaction, ________________________ are changed into _______________________.

• Reactants; Products

• Electrons; Molecules/Compounds

• Coefficients; Subscripts

• Original Elements; New Elements

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is a chemical reaction?

• Water freezes.
• Sugar dissolves in water.
• Salt and pepper are mixed in a dish.
• Iron rusts.

Tags

NGSS.MS-PS1-2

When two substances were combined, bubbles were produced and the temperature dropped.  This most likely means that:

• a chemical reaction took place
• the two substances had low boiling points
• one substance dissolved in the other
• the two substances are non-reactive

Tags

NGSS.MS-PS1-2

Before a chemical reaction, the total mass of two reactants is measured to be 40 grams.  After the reaction, what should be the total mass of the products?

• 0 grams
• 20 grams
• 40 grams
• 80 grams

Tags

NGSS.MS-PS1-5

Suppose two substances were combined together in a beaker. You know that a chemical reaction occurred if:

• new substances were created.
• one substance dissolved in the other.
• one substance melted in the other.
•  the two substances remained separate.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

All of the following are indicators of a chemical reaction except one.  Which one is NOT an indicator that a chemical reaction has taken place?

• he production of heat or light
• a color change
• the production of gas bubbles
• the dissolving of one substance in another

Tags

NGSS.MS-PS1-2

The law of conservation of matter states that:

• matter is neither created nor destroyed.
• the mass of the products is always greater than the mass of the reactants.
•  the mass of the products is always less than the mass of the reactants.
• matter is always converted into an equal amount of energy.

What type of chemical reaction is burning paper?

• Chemical

• Physical

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following 2 are chemical reactions?

• sugar dissolving in water

• water turning into steam

• burning wood

• mixing baking soda and vinegar

• tearing paper

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5