1st Quarter Chemistry 2012: Unit Conversion

Unit Conversions Worksheet

1)        How many inches are there in 45.6 cm?  (There are 2.54 cm in 1 inch)

2)        How many centimeters are there in 1.23 x 10^-6 kilometers?

3)        How many hours are there in 34.5 years?

4)        How many inches are there in 355 millimeters?

5)        How many milliliters are in a cubic meter?  (There are 1,000 L in 1 m³)

6)        How many miles are there in 3.44 x 10⁸ inches?  There are 0.61 miles in 1 km).

Unit Conversions Worksheet - Solutions

1)        How many inches are there in 45.6 cm?  (There are 2.54 cm in 1 inch)

            18.0 inches

2)        How many centimeters are there in 1.23 x 10^-6 kilometers?

            0.123 cm

3)        How many hours are there in 34.5 years?

            3.02 x 10⁵ hours

4)        How many inches are there in 355 millimeters?

            14.0 inches

5)        How many milliliters are in a cubic meter?  (There are 1,000 L in 1 m³)

            1.00 x 10⁶ mL

6)        How many miles are there in 3.44 x 10⁸ inches?  There are 0.61 miles in 1 km).

            5.33 x 10³ miles

1st Quarter Chemistry 2012: Reviewer

Time Frame: 5 mins
Source: http://www.avon-chemistry.com/nuclear_practice.htm

Hi everyone! 
This is a quick test for chapters 4 and 5 of our textbook. Have fun!

MULTIPLE CHOICE:

1. 1.      Cathode rays are:

A

negatively charged particles

B

positively charged particles

C

nuclei of a helium atom

D

fast moving neutrons

1. 2.     The neutral atoms of all of the isotopes of the same element have:

A

the same mass numbers

B

equal numbers of neutrons

C

the same number of electrons

D

different number of protons

1. 3.      Which statement is true about an isotope?

A

There can be more than one type of isotope for an element.

B

All isotopes for an element has the same number of protons and the same mass number.

C

Isotopes can have different numbers of protons.

D

All isotopes are not radioactive.

1. 4.      How many electrons are in an oxygen atom?

A

2

B

6

C

8

D

10

1. 5.  Copper has an atomic mass of 63.5 amu. Why is the atomic mass NOT a whole number?

A

All copper atoms have identical chemical properties.

B

The fractional number results from the fact that protons and neutrons have different masses.

C

Every copper atom has an atomic mass of 63.5 amu.

D

There are at least two naturally occurring isotopes of copper.

1. 6.      Which symbol represents an atom that contains the largest number of neutrons?

 

A

U-235

B

Pa-231

C

Np-239

D

Pu-240

E

U-239

7. The number of protons in fluorine-23 is 

A

6

B

8

C

9

D

14

E

23

8. Find the average mass of an element if the relative amounts are as follows:
   Isotopic Mass: Percentage:
   75 amu ----------- 2.3%
   77 amu ----------- 15.7 %
   78 amu ----------- 4.5 %
   80 amu ----------- 7.1 %
   81 amu ----------- 70.4 % 

A

77.25 amu

B

78.01 amu

C

79.09 amu

D

80.03 amu

E

81.09 amu

9. Which of the following is NOT true about chemical reactions? 

A

After a chemical reaction, the protons and neutrons within the atom have not changed.

B

After a chemical reaction, there are new bonds formed while others bonds were broken.

C

After a chemical reaction, an electron may enter the nucleus and change a proton to a neutron.

D

After a chemical reaction, the boiling points and melting points of the new products are different.

10. How many protons, neutrons, and electrons are in one atom of Pb-212 (atomic number 82)?

A

212 p+, 82 n0, 212 e-

B

82 p+, 212 n0, 212 e-

C

82 p+, 212 n0, 82 e-

D

82 p+, 82 n0, 212 e-

E

none of the above are correct

Did you have fun? Here are the answers!

1. a

2. c

3. a

4. c

5. d

6. e

7. d

8. d

9. c

10. e

1st Quarter Chemistry 2012: Significant Figure Calculations

Significant Figure Calculations

Figure out how to do calculations using the magic of significant figures. 

Solve the following mathematical problems such that the answers have the correct number of significant figures:

1)        334.54 grams + 198 grams = ___________________

2)        34.1 grams / 1.1 mL = ___________________

3)        2.11 x 10³ joules / 34 seconds = ___________________

4)        0.0010 meters – 0.11 m = ___________________

5)        349 cm + 1.10 cm + 100 cm = ___________________

6)        450 meters / 114 seconds = ___________________

7)        298.01 kilograms + 34.112 kilograms = ___________________

8)        84 m/s x 31.221 s = ___________________

SPOILER ALERT!!!     SPOILER ALERT!!!    SPOILER ALERT!!!     SPOILER ALERT!!!     SPOILER ALERT!!!

     

Significant Figure Calculations – Answers

Solve the following mathematical problems such that the answers have the correct number of significant figures:

1)        533 grams (rounded from 532.42 grams)

2)        31 g/mL (not rounded)

3)        62 J/s (rounded from 62.0588 J/s)

4)        -0.11 m (rounded from -0.109 m)

5)        500 cm (rounded from 450.1 cm)

6)        3.9 m/s (rounded from 3.9474 m/s)

7)        332.12 kg (rounded from 332.122 kg)

8)        2600 m (rounded from 2622.564 m)