Chem midterm

pt. 1

6 postulate of Kinetic Molecular Theory

1. Gasses are in a constant random motion

2. Gasses move in a straight line, until they collide with another particle or wall

3. Much empty space in gas/particles are smaller than distance between them

4. no force of attraction

5. collisions are elastic(no energy lost)

6. speed depends on temp of gas

table

solid

How is plasma different than a gas?

Plasma is different from a gas because it is so extremely hot, that it ionizes, meaning the electrons are unable to relax onto the atoms that make up the plasma matter.

Aluminum, Lead, Helium, Lithium

ELEMENTS

Water, Sulfuric Acid, Rust, Nitrous Oxide

Compounds

M&Ms, Humans, Beach Sand, Oobleck, Gasoline

Hetergenous

Air, Aluminum Foil, Grape Juice, Tea

Homogenous

What is the difference between a pure substance and a mixture

A pure substance consists of elements of the same kind or 2 or more elements of different kinds that are CHEMICALLY BONDED TOGETHER, in a mixture, compounds of pure substances are joined together but are NOT CHEMICALLY BONDED.

3 physical properties of a lime

green, oval, sour

State 3 chemical properties of plutonium

Combustibility, reactivity, radioactivity

(7) State ALL evidence that supports physical change has occurred:

- change in shape

- change in size

- change in mass

- change in volume

- change in density

- change in state of matter (phase change)

- change in superficial appearance (coloring a picture, painting a wall, etc.)

(9)State ALL evidence that supports a chemical change has occurred:

- change in color

- formation of bubbles

- endothermic

- exothermic

- release of gas

- formation of a precipitate(rain, hail)

- oxidation

- change in odor

- decomposition

chemical or physical- cracking an egg

physical

chemical or physical- a rusting nail

chemical

chemical or physical- bomb exploding

chemical

chemical or physical- making a sandwich

physical

chemical or physical- AS+ Water

Chemical

chemical or physical- book page rips

physical

chemical or physical- digesting a pizza

chemical

chemical or physical- painting a wall

physical

chemical or physical- frying an egg

chemical

What is the density of the following cube if it has a mass of 120 g?(7.6 length)

2.7 x 10^-1 g/cm³

if an object is hot it is moving…

fast

If an object is really hot it does not have a lot of energy!

NO it has a lot of energy

how many kinetic postulates are there?

6

What do the slopes on the phase change diagram represent?

Temperature and Energy increasing in a single phase

what is plasma?

hot gas with high energy and charged ions

Which of the following is NOT a heterogeneous mixture?

Saltwater

how much is measured in the glass

36.0 mL

what are the 4 basic units of the metric system?

m, L, g. s

0.00009023 4 sf

9.023 × 10^-5

84600000 3sf

8.46 × 10⁷

(23.44+6)/(902×4.5)

2.2 × 10^-2

Write 4 different numbers that follow each of the 4 rules of significant figures, as if you were teaching it to someone else.

1. Zeros DO count if there is a decimal ex. 13.00, 4 sf

2. All nonzeros are significant

3. Zeros in between nonzeros are always significant

4. Leading zeros are NEVER significant

How many sig figs in 24?

2 sf

How many sig figs in 8009

4sf

How many sig figs in 0.992034

6 sf

How many sig figs in 30.40020

7sf

How many sig figs in 800000000

1sf

How many sig figs in 0.9000

4sf

23.4×14

3.2 × 10²

7.895 +3.4

11.2

0.0945 ×1.47

1.38×10^-1

689g to ug

6.89×10^-4 ug

where does the 1 go when you do pick fencing? (prefix or no prefix?)

Prefix

400.99Mg to g

4.0099 × 10⁹g

58.9×10^-5pg to cg

5.89 × 10^-14cg

density equation

d=m/v

How can you determine whether an object will sink or float?

if it is less than 1

Closely packed together, has a definite shape and volume (tightly compact)

solid

can move past each other

liquid

particles moves freely

gas

charged particles; electrons unable to relax

plasma

is the formation of bubbles chemical or physical?

chemical

chemical or physical: change in shape/size

physical

chemical or physical:change in mass/volume/density

physical

chemical or physical: change in state of matter

physical

chemical or physical: change in superficial appearance (paint on wall)

physical

chemical or physical: release of gas

chemical

Is Windex a homogeneous mixture?

Yes

Is water homogeneous?

no compound

Is salad dressing heterogeneous, homogeneous, compound, or element?

hetergenous

Air is homogeneous?

Yes

Which is NOT a phyiscal property: acidity/taste/color/solubility

acidity

Which is NOT a chemical property combustibility/flammability/mallability/oxidation?

malleability

how many protons does calcium have

20

how many electrons does calcium have?

20

The goal is 50 g; the results show 49 g, 50 g, 48 g, 51 g, 50 g. The results were:

accurate and precise

How many sig figs are in the following value: 0.0000300405000

9

A 12 g object is placed in a grad cyl that read 10 mL but after placement reads 16 mL. Density of object?

2 g/mL

how to find density for a cube?

m/s³

What do the slopes on the phase change diagram represent?

Temperature and Energy increasing in a single phase

composed of only one type of atom or molecule

pure substance; elements/compounds

composed of only one type of atom

element

composed of 2 or more different elements that are chemically bonded

compounds

composed of 2 or more pure substances

mixtures

non uniform consistency throughout; can be separated by physical means

heterogeneous

uniform mixture, can’t be separated physically

homogenous

gold, diamond, iron, helium, and uranium are examples of??

elements

water, glass, salt, sugar, hydrochloric acid, rubbing alcohol, carbon dioxide, homoglobin, meth are examples of

compounds

gasoline, chexmix, salad, beach sand, paint, milk, soda, soup, people are examples of

Heterogeneuos

air, steel, milk, coffee, wine, and lemon juice are examples of

homogeneous

accuracy is…

how close you are to the true value

precision is…

mutiple values within the range of one another

how does temperature affect the energy of particles?

the higher the temperature, the higher the energy and therefore higher speed of the particles

Solid-melts-liquid-vaporization-gas (opposite?)

gas-condensation-liquid-freezing-solid

200.00 how many sf

5 sf

89.7 g sample of lead is placed in a cylinder of water that first reads 45.3mL, after it reads 53.2. What is the density of lead sample?

1.1 × 10¹ g/mL

what else is plasma other than stars?

lightning

examples of gasses?

oxygen, carbon dioxide, nitrogen, hydrogen, helium, steam