Chemistry Middle School

6. Different liquids have different freezing points mainly because

• a) Freezers are at different temperatures

• b) Some winters are colder than others

• c) The less liquid you use, the faster it freezes

• d) Molecules of different liquids have a different amount of attraction

Tags

NGSS.MS-PS1-4

If two objects have the same volume but one has a greater mass, the one with greater mass

• Has a lower density

• Has a higher density

• Will float

• Will sink

An object should float in a liquid if it is

• More dense than the liquid

• Less dense than the liquid

• Lighter than metal

• Shaped like a ball

Protons are located in the nucleus of the atom. A proton has

• No charge

• A negative charge

• A positive and a negative charge

• A positive charge

12. Neutrons are in the nucleus of the atom. A neutron has

• a) A positive charge

• b) No charge

• c) A negative charge

• d) Twice as much positive charge as a proton

An electron is in a region outside the nucleus. An electron

• Is larger than a proton and has no charge

• Has less mass than a proton and has a negative charge

• Is smaller than a proton and has no charge

• Has a positive charge

The atomic number of nitrogen is 7. The atomic mass is 14.01. This means that

• All nitrogen atoms have exactly 7 neutrons.

• A small percentage of nitrogen atoms have fewer than 7 neutrons

• A small percentage of nitrogen atoms have more than 7 neutrons

• Some nitrogen atoms have fewer than 7 electrons

Tags

NGSS.MS-PS1-1

The water molecule is a polar molecule. A water molecule is polar because

• The electrons are shared equally

• Oxygen has a stronger attraction for electrons than hydrogen

• It is very cold

• Hydrogen atoms have a stronger attraction for electrons than oxygen

19. One clue of a chemical change is the formation of a precipitate. A precipitate is formed when

• a) Two liquids react and a gas is produced

• b) A solid dissolves in a liquid

• c) One liquid dissolves in another

• d) Two liquids react and a solid is formed

Tags

NGSS.MS-PS1-2

When the pH of a solution becomes more acidic, the number on the pH scale

• Decreases

• Increases

• Stays the same

• Doubles