Honors Chemistry Midterm

What is the definition of matter?

Anything that has mass and takes up space

An example that is NOT matter

Time, sound, thoughts….etc

Steps of the Scientific Method (in order)

1. Ask a question/make observation

2. Make a hypothesis

3. Do an experiment

4. Record & analyze data

5. Form a conclusion

Qualitative Observation

Describe something using words

Quantitative Observation

Describe something using numbers and are usually made with instruments

What 2 words does a well written hypothesis USUALLY contain?

If/Then

What is the definition of a dependent variable?

Part of the experiment that the scientist observes or measures to see if the hypothesis is correct

What is the definition of an independent variable?

Part of the experiment that the scientist change

Chemistry is defined as the study of what?

Study of matter & the changes it undergoes

What is the definition of a physical change?

A change that does NOT produce a new substance (change in 1 or more physical properties)

What is the definition of a chemical change?

A change produces a new substance with different properties

Crushing a can is a…..

Physical change

Cutting a pizza is a…

Physical change

A silver ring tarnishing (Ag – Ag2S)

Chemical Change

Burning a log until it becomes ash is a….

Chemical Change

All phase changes (changing 1 substance from a solid-liquid-gas) are….

Physical

How are temperature and kinetic energy related?

Temperature is a measure of the average kinetic energy of particles

What happens to temperature during a phase change? What is happening to the particles during a phase change?

Temperature remains constant even though heat is being added or removed. Heat energy is being used to change the intermolecular forces

Which state(s) of matter expands to fill their container?

Gases

Which state(s) of matter take the shape of their container?

Liquids & gases

Which state of matter has the most kinetic energy? Why?

Gases - particles are moving the most/fastest

Which state of matter has the strongest intermolecular forces? Why?

Solids - particles are very close together & very attracted to neighbors

What is the definition of a compound?

Atoms of 2 or more different elements that are chemically combined

What is the definition of a mixture?

2 or more elements and/or compounds that are physically combined

What is an extensive property?

Depends on amt. of matter (Mass & Volume)

What is an intensive property?

Only depends on type of matter

Compound

Compound

Compounds and Elements

Pure element

Determine the number of atoms of each element is Ca(NO3)2

Ca = 1, N = 2, O = 6

What is the law of conservation of matter and how is it upheld in chemical equations?

Matter/atoms are neither created nor destroyed during chemical reactions. They are rearranged. This is why chemical equations must be balanced.

What is the symbol for the states of matter (solid, liquid, gas, and aqueous solution) in a chemical equation?

• Solid - (s)

• Liquid - (l)

• Gas - (g)

• Aqueous solution - (Aq)

What is the definition of a reactant? Where are they located in a chemical equation?

Starting substance in a chemical reaction / before the arrow

What is the definition of a product? Where are they located in a chemical equation?

Substance that is made/produced during a chemical reaction / after the arrow

What is accuracy?

How close a measurement is to the true value

What is precision?

How close a group of measurements are to each other

What is the equation for calculating density?

*Hint: think of 6=3/2

D=M/V

What is the equation for calculating volume?

V=M/D

What is the equation for calculating mass?

M=DxV

What is a proton?

A positively charged subatomic particle

What is an electron?

A negatively charged subatomic particle

What is a neutron?

A neutral subatomic particle

Where is the nucleus located in an atom?

The center

What 2 subatomic particles are located in the nucleus?

Protons and neutrons

Who discovered the nucleus?

Rutherford

What was the name of his experiment?

Gold Foil experiment

What is the definition of an atom?

Smallest part of an element that has its physical and chemical properties