Chemistry Unit Test

Phys/Chem properties and changes

100

Two examples of Physical properties

Color

smell

mass

temp

Boiling point  or Melting point

200

Phase change is a physical change. Explain why

Because Nothing New is Formed!

300

 Dissolving a physical change. Prove it. 

For example,  dissolve sugar in water, if you evaporate the water, crystals of sugar will be left behind. Nothing new is Formed, so it is a physical change.

400

What is Chemical change? What are some signs of chemical change?

Chemical change is when substances react and something new is produced . Signs of Chemical change:

color change, smell change, fizzing/bubbling, light produced, heat given off or taken in.

500

When baking soda and vinegar combine they fizz and bubble. This is a sign of chemical change. Explain why.

The fizzing and bubbling when baking soda and vinegar combine show that a gas is produced. Any time a new substance is produced , it is a chemical change. 

E, C, M

100

Smallest part of an Element

Atom

200

Smallest part of a compound 

Molecule

300

Difference between Mixture and Compound

In a compound the substances that make it are bonded together but in a Mixture the substances are not bonded together

400

Kumar adds salt to water till the salt disappears. Is this a Mixture ? If so, what type of mixture (choose a/b):

a. Homogeneous

b.Heterogeneous

Yes 

a. Homogeneous

500

Why are elements and compounds called pure substances

They are made up of only one type of particle

Atomic Structure

100

What subatomic particles make up an atom's nucleus

Protons and Neutrons

200

What is atomic number? 

The identity of an atom which is the number of protons ( also the number of electrons)

Protons are Positive particles and Electrons are Negative particles . An Atom is Neutral when they have an equal number of Protons and Electrons. 

300

What is atomic mass (a.k.a atomic weight) ? 

Protons + Neutrons

400

How many electrons does Oxygen have ? How do you know

Oxygen has 8 electrons 

Atomic number of Oxygen = 8 

Atomic number = Number of protons  (and also the Number of electrons)

500

Outermost  electrons for an atom is called the _______ electrons. 

How do they relate to reactivity? 

Valence electrons

Atoms want full valence shell, if they don't have full valence shell they react to get a full valence shell.

Bonding

100

An atom becomes an ion when it gains or loses _______

Electrons

200

Giving or Taking electrons which happens between metals and non-metals is called ________ bond

Ionic

300

Sharing of valence electrons to get a full valence shell is called __________ bonding

Covalent

400

Draw Bohr Model for Sodium (Na)

On the white board

500

Draw Lewis Dot model for Aluminum (Al)

Draw on the white board

Chem Formulas and Equations

100

Identify the reactants in this chemical reaction:          Zinc + Hydrochloric acid --> Zinc chloride + Hydrogen gas

Zinc and Hydrochloric acid

200

What is true about the equation :

H₂O_{2 ----->} H_{2  +} O₂

It represents  a chemical reaction

300

What does the subscript 2 in Na₂SO₄ mean?

There are 2 atoms of Na bonded into Na₂SO₄

400

Matter is neither created nor destroyed. In a chemical reaction you always end up with the same amount of stuff as you started with. What is this law? 

Law Of Conservation of Mass

500

Chemical Formula for Propane

Teacher will draw the molecule on the whiteboard and the students have to identify the chemical formula