CHM 251-CHAP 1

Properties of matter

100

Which term does not describe a conversion between states of matter? Also explain why:

a.) condensation

b.) melting

c.)evaporation

d.)freezing

e.)mixing

e.) mixing

 because when you mix substances, you are simply combining them without changing their individual states of matter.

200

Which elements belong in same group?

1.) C, N, O

2.) Al, Ge, sb

3.) F, Cl, Br

4.) B, Si, As

5. Fe, Cu, Ni

3.) F, Cl, Br

groups are vertical lines (18) on periodic table

300

Which element is represented by chemical symbol K?

kaolin

sodium

potassium

silver

phosphorus

potassium

400

Air, which contains nitrogen, oxygen, and other gases, is an example of:
A) Mixture
B) Compound
C) Element
D) Solution

A) Mixture

500

 Oil floating on water is an example of:
A) Homogeneous mixture
B) Heterogeneous mixture
C) Compound
D) Pure substance

B) Heterogeneous mixture

scientific notation

100

write in scientific notation

61500 cm

6.15 x 10⁴ cm

200

write in scientific notation

0.0355 m

3.55 x 10^-2 m

300

Write in standard notation 

9.595 x 10⁵

959500

400

Write in standard notation

7.98 x 10^-6

0.00000798

500

Calculate and then convert to standard notation

(5.3 x 10⁹)(3.1 x 10^-3) / (5.0214 x 10⁵)

3.27×10¹=     32.7

SIG FIGs

100

how many SIG FIGs?

55

2

200

how many sig figs?

50

1

300

how many sig figs?

0.620

3

400

how many sig figs?

2056

4

500

how many sig figs?

0.00560

3

SIG FIGS with operations

100

calculate and use proper sig figs

123.456 + 7.8 + 0.0091 

131.3

200

calculate and round to proper sig figs:

0.00456 + 0.0789 − 0.00032=

0.0831

300

calculate and round to proper sig figs

0.0567 × 12.34= 

0.700

400

calculate and round to proper sig figs

14570 kg ÷ 5.81 L

2510 kg/L

500

calculate and round to proper sig figs

(12.345 + 0.6789) ÷ 3.21=

4.06

Unit conversions

100

8.88 km to nm 

8.88 x 10¹² nm

200

If 25.0 g of olive oil has 850 cal of heat added to it at a room temperature of 24.0 °C, what will be the final temperature of the olive oil?
The specific heat of olive oil is 2.19 cal/g °C.
Submit your answer in standard notation in °C and with proper significant figures.

Use the formula:

Tf = Ti + q / (m × c)

 

 q is heat

= 24.0 + 850 / (25.0 × 2.19)
= 24.0 + 850 / 54.75
= 24.0 + 15.5
= 39.5 °C  

300

What is the volume in cm³ of a gold nugget that weighs 15 kg? The density of gold is 19.0 g/cm³. Report your answer with the proper significant figures in standard notation.

Given
Mass = 15 kg = 1.5 × 10⁴ g
Density = 19.0 g/cm³

Volume = mass ÷ density
1.5 × 10⁴ g ÷ 19.0 g/cm³ 

= 7.9 × 10² cm³

400

The dosage of quinine when a 125 Ib adult takes a 2.5 mg tablet is mg drug per kg of body weight. (2.20 pounds = 1.00 kg). Report your answer in standard notation with proper significant figures.

125 lb × (1 kg / 2.20 lb) = 56.8 kg
2.5 mg ÷ 56.8 kg = 0.044 mg/kg (2 sig figs)

Answer: 0.044 mg/kg

500

An extra-strength aspirin contains 0.500 g of aspirin. How many grains is this?

(1 grain = 64.8 mg)

Given
0.500 g aspirin
1 grain = 64.8 mg

Convert g → mg
0.500 g × 1000 mg/g = 500 mg

Convert mg → grains
500 mg ÷ 64.8 mg/grain = 7.72 grains

0.500 g has 3 sig figs, so:

Answer: 7.72 grains