REVIEWUnit 1: Measurement & Matter

IMPORTANT DATES Unit 1 exam on Wed. Oct. 1

Lab tomorrow: Tues. Sept. 30

Pre-lab quiz (online) due by tomorrow 8am

1) 273K = __________ °C0

273 K - 273 = 0°C

2) How many sig figs are in: 0.00350

3 sig figs

Decimal PresentCount from Pacific (left side)

disregard initial zeros

3) How many sig figs are in: 750000

2 sig figs

Decimal AbsentCount from Atlantic (right side)

disregard initial zeros

4) A metal block has the following dimensions:

L = 0.5 cm W = 0.15 cm H = 0.25 c m

How many sig figs should appear in the final answer for the volume of the metal block?

1 sig fig

5) What are two ways to measure volume?

1) Water displacement2) Multiplying dimensions

(LxWxH)

6) What is the density in g/cm3 of a metal block that has a mass of 1000 mg and a volume of 10 cm3?

1000 mg = 1 g

D = 1 g / 10 cm3 = 0.1 g/cm3

7) Will the metal block from the previous question (d=0.1 g/cm3) sink or float when placed in water?

It will float when placed in water because its density is less than the density of water, 1.0 g/cm3.

8) A copper penny has a density of 8.9 g/cm3 and a volume of 0.35 cm3. What is the mass of the copper penny? Round your answer to the appropriate number of significant figures.

m = d*v = 8.9 g/cm3 x 0.35 cm3

m = 3.115 g 2 sig figs 3.1 g

9) Calculate the percent error in the last problem (we calculated 3.1 g) if the accepted mass of a copper penny is 3.2 g. Round your answer to the appropriate number of significant figures.

% error = (3.2-3.1)/3.2 * 100%% error = 3.125% 2 sig figs 3.1%

10) Give one physical property and one chemical property of the element copper, Cu.

Physical property = color; density; BP; MP (from Table S)

Chemical property = ability to oxidize//rust

11) What is one difference between a compound and a mixture?

Compounds are homogeneousMixtures can be both homogeneous & heterogeneous.

In a compound, the properties of the individual components are different when separatedIn a mixture, the individual components retain their properties.

Mixtures can be physically separated.Compounds cannot be physically separated.

12) What is one difference between an element and a compound?

Elements cannot be broken down chemically.Compounds can be broken down chemically.

Elements are made of atoms of the same element.Compounds are atoms of different elements chemically bonded.

13) What does (aq) represent?EX: NaCl(aq)

Aqueous = NaCl(s) dissolved in H2O(l)

AKA solution

AKA homogeneous mixture

14) How could you physically change a piece of paper?

Crumple it; tear it; fold it; etc…

15) How could you chemically change a piece of paper?

Burn it

16) Is the water cycle considered a chemical change or physical change? Explain.

Physical change because the water undergoes changes in phases (or states) of matter. Therefore, the composition remains the same.

H2O (s) ↔ H2O (l) ↔ H2O (g)

17) Define the Law of Conservation of Mass & give an example.

Mass is neither created nor destroyed.

Examples vary…

18) Which of the following represents a mixture?

A. HCl (s)B. HCl (l)C. HCl (g)D. HCl (aq)

D

19) What is always the first step of the Scientific Method?

Identify the problem or question to be answered.

20) What is always the last step of the Scientific Method?

Write a conclusion statement.

21) How could you separate a mixture of salt water?

Distill or evaporate the water.

22) Explain the effectiveness of a distillation for a mixture of two substance with boiling points of 80°C and 90°C.

A distillation would not be effective because the boiling points are too close together.

23) You filter a mixture of oil and vinegar. What will pass through the filter?

Both the oil & vinegar.

24) You filter a mixture of mud (water and dirt). What will pass through the filter?

Just the water

25) You distill a mixture of acetone (BP=56°C) and water (BP=100°C). Which of the substances will distill first & be collected in the receiving flask?

Acetone

TEST ON WED. 10/1

TOPICS TO REVIEW Temperature

conversions (K & °C) Sig Figs Sig Figs in calculations Scientific Method –

know the steps Matter Substances aka pure

substances Elements Compounds Mixture Mixtures versus

compounds

Solutions (aq) Heterogeneous Homogeneous Physical property Chemical property Physical change Chemical change Law of Conservation

of Mass Mass, Volume, and

Density calculations Percent error

calculations