8th Grade Science Review

AMEC

100

What does the atomic number tell us on the periodic table?

The number of protons an atom has

200

What is the difference between a heterogeneous and homogeneous mixture?

heterogeneous- has "chunks" not uniform- fruit salad

homogeneous- uniform/one consistency- milk

300

What is the charge of a proton, neutron, and electron?

proton- positive +

neutron- no charge 0

electron- negative -

400

How can you find the number of neutrons from a box on the periodic table?

atomic mass-atomic number

500

What is the difference between an ion and an isotope?

ion- an atom that lost or gained an e- (has a net charge)

isotope- an atom with a varying number of neutrons

Physical and Chemical Change

100

What is the difference between a physical and chemical change?

physical- does not change the identity of a substance (ex: changing state of matter)

chemical- changes the identity of a substance (cannot get back to original)

200

What does the Law of Conservation of Mass say?

Matter/Mass cannot be created or destroyed.

300

What is the difference between an open and closed system?

open- interacts with the environment

closed- does not interact with the environment

400

What is the difference between a coefficient and a subscript

coefficient: 2CO (in front)

subscript: CO₂  (below) 

500

Balance the following equation: 

____Xe + ____F_{2-----> _____}XeF₆

_1___Xe + __3__F_{2-----> ___}1_{__}XeF₆

Measurement

100

How many centimeters are in a meter?

100 cm

200

What is the best piece of equipment to measure a small amount of liquid precisely?

A small graduated cylinder.

300

What is the difference between mass and weight?

mass- the amount of "stuff" an object has. Does NOT change based on what planet you are on

weight- depends on gravity (m x g= weight)

400

What tools could I use to measure mass?

triple beam balance

electronic balance 

500

Explain how to find the volume of an irregularly shaped object?

water displacement 

Energy and Heat Transfer

100

What unit is energy measured in?

Joules

200

How do you find total mechanical energy?

Potential energy + Kinetic energy

300

What factors affect GPE?

mass and height

400

Give an example of each type of heat transfer

conduction: a pot on a stove

radiation: the sun warming the earth

convection: ocean currents/boiling soup

500

Give 2 examples of chemical energy.

gasoline

food

Forces and Motion

100

What factors affect gravity and how?

mass- more mass= greater gravity

distance- further distance= less gravity

200

What is the difference between speed and velocity?

speed- distance/time

velocity- has direction

300

What factors affect friction?

mass and surface material

400

Describe inertia and give an example.

The tendency for an object to keep doing what its doing.

When you hit the brakes in a car your body flies forward.

500

If you are driving 40mph north and pass a car on the highway going 35 mph north, what is that car's motion from your frame of reference?

5 mph south