Chemistry Middle School

14. The atomic number of an atom is

• a) The mass of the atom

• b) The number of protons added to the number of neutrons

• c) The number of protons

• d) Negatively charged

Tags

NGSS.MS-PS1-1

The atoms in a water molecule are held together by covalent bonds. This means that the bonded atoms

• Lose protons

• Lose electrons

• Share electrons

• Switch neutrons

Some chemical reactions require a substance called a catalyst. The main purpose of a catalyst is

• To warm up the reaction

• To speed up the reaction

• To create more reactants

• To stop the reaction

If two substances react and the temperature of the mixture increases, the reaction is

• Endothermic

• Not one that produces anything new

• One that needs a catalyst

• Exothermic

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

If two substances react and the temperature of the mixture decreases, the reaction is

• Endothermic

• Never going to happen unless it is heated

• Exothermic

• one that causes atoms to be destroyed

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

In a chemical reaction, if the reactants are heated, the reaction usually happens

• Faster

• Slower

• At the same rate

• In a smaller volume

When a thermometer is heated, the red liquid inside the thermometer moves up.This is mainly because:

• The red liquid is thin.

• The molecules of the liquid move faster and get a little further apart

• Hot liquid is lighter

• The glass of the thermometer gets hot

Tags

NGSS.MS-PS1-4

2. When you heat a sample of a solid, the sample gets a little bigger.This is mainly because:

• a) The particles move faster and get a little further apart
• b) Heat helps the particles grow
• c) Heating the sample makes it lighter
• d) Heating helps the particles slide past each other

Tags

NGSS.MS-PS1-4

In the process of conduction

• Fast-moving particles get larger

• Slow-moving particles get smaller

• Fast-moving particles transfer energy to slower-moving particles

• Slow-moving particles transfer energy to faster-moving particles

Tags

NGSS.MS-PS3-5

Hot water evaporates faster than room temperature water. This is mainly because

• Molecules of hot water are lighter

• More water molecules move fast enough to break away from other water molecules

• Room temperature water has more mass

• The molecules in room temperature water are moving faster

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4