Practice Problems Solutions for Midterm 1 - General Inorganic Chemistry | HCHE 111G, Exams of Inorganic Chemistry

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Chemistry 111 – Elementary Inorganic Chemistry

Midterm Examination #1 — Solutions to

PRACTICE PROBLEMS

Name: ________________________

1. For each of the following questions, circle the BEST answer (no explanation is required for full credit).

a. A particular model of “hybrid” car can travel 53.0 miles/gallon of gas. What is this fuel efficiency expressed in metric units (km/L)? Recall that 1 gal = 3.78 L.

22.5 km/L 20.2 km/L 8.71 km/L 20.2 km/gal 90 km/L

b. Which of the following instruments is used to measure the pressure of a gas sample?

an altimeter a barometer an odometer a manometer a graduated cylinder

A manometer measures the pressure of a gas relative to the external atmospheric pressure.

c. An ideal gas at STP in a sealed container expands at constant temperature until its volume ( V ) has quadrupled. That is, Vfinal = 4Vinitial. Which of the following is true?

nfinal = 4ninitial Pfinal = ¼Pinitial Tfinal = ¼Tinitial Pfinal = 4Pinitial Tfinal = 4Tinitial

Boyle’s law (constant n,T) tells us that the pressure of a gas sample is inversely related to it’s volume.

d. At constant pressure the temperature of a 4.00 L sample of gas is increased from 25 °C to 50 °C. What is the new volume of the gas sample?

8.00 L 2.0 L 0.25 L 4.34 L 3.69 L

e. An object weighs 75.7 kg. What is the weight of this object expressed in the English system? Recall that 1 kg = 2.204 lb.

343 lbs 167 lbs 167 g 16.7 lbs 34.3 lbs

gal

2 2.5km 1000 m

1 km 100 cm

1 m 1 in

2 .54cm 1 ft

12 in 1 mile

5280 ft 3.78L

1 gal gal

53. 0 miles × × × × × × =

4. 34 L

(298K)

(4.00L)(323K)

T

VT

orV T

V

T

V

Sincen,Pareconstant,applyCharles'Law: 1

1 2 2 2

2 1

167 lb 1 kg

2.204lb

75. 7 kg× =