Final Review

Match the following:

• heterogeneous mixture

• salt water (NaCl and H2O)

• homogenous mixture

• carbon (C)

• element

• taco salad

• compound

• carbon monoxide (CO)

Answer explanation

Elements are made of only 1 type of matter. Their symbols will have only one capital letter. Compounds are 2 or more elements chemically combined. The symbol will have more than 1 capital letter. Mixtures are physically combined. Heterogeneous mixtures are different throughout. Homogeneous mixtures are the same throughout,

taco salad

• compound

• element

• heterogeneous mixture

• homogeneous mixture

Answer explanation

Mixtures can be physically separated. "Hetero" means different. Heterogeneous mixtures are not the same throughout.

Steel has a density of 7.8 g/cm3. What is the mass of a block of steel with a volume of 600 cm3?____ g

Mathematical Equivalence

ON

Which scientist developed the model of the atom shown here?

• Bohr

• Chadwick

• Rutherford

• Thomson

Answer explanation

Thomson experimented with cathode ray tubes and discovered electrons. He explained atoms as being positively charged with negative charges embedded within it - like plums in plum pudding.

Which scientist used the gold foil experiment to determine that an atom contains a dense positively charged core with a lot of empty space?

• Chadwick

• Bohr

• Thomson

• Rutherford

Answer explanation

Ernest Rutherford fired alpha particles at a thin sheet of gold foil. Most of the alpha particles went straight through but some were deflected and some were reflected. This led Rutherford to change the model of the atom to one having a dense positively charged nucleus surrounded by empty space.

Which of the following is a chemical change?

• Dog tore up homework.

• Ice melted

• Milk turned sour

• Glass broke.

Answer explanation

A chemical change creates a new substance which has different properties. Signs of a chemical change are a change in color or odor, gas forms, precipitate formed, change in heat or light. Physical changes do not create new substances.

Match the following

• melting

• solid directly to a gas

• freezing

• liquid to gas

• condensation

• solid to liquid

• evaporating

• gas to liquid

• sublimation

• liquid to solid

A substance has a mass of 360 g and a volume of 7.5 cm3.  What is its density?____ g/cm3

Mathematical Equivalence

ON

Answer explanation

D=m/v

Lead has a density of 11.3 g/cm3.  What is the volume of a block of lead with a mass of 282.5 g?____ cm3

Mathematical Equivalence

ON

This element's atomic number is ​ (a)   . It has a mass number of ​ (b)   . It's charge is ​ (c)   . What element is it? ​ (d)  

• 4
• 9
• neutral
• beryllium
• 13
• positive
• negative
• boron
• fluorine

Answer explanation

Atomic number is the number of protons. Mass number is the number of protons plus neutrons. Charge equals protons minus electrons. The atomic number determines the element. Atomic number 4 is beryllium.