Miami Dade College, Miami - CHEM 1025 Unit 1 Review (Chapters 1-3) 1)Write the following numbers in scientific notation

Miami Dade College, Miami - CHEM 1025

Unit 1 Review (Chapters 1-3)

1)Write the following numbers in scientific notation.

 a.   770000000=

b. 2520=

c.   0.000002224=

d. 0.004=

2. Express each number in decimal notation

 a.   1.5 X 10²=

b. 3.0 X 10^-5=

3. How many significant figures are there in each of the following values? a) 6.07 X 10^-22; 3

b) 0.00038400;

c) 17.00;

d) 8;

e) 854000;

f)    8.2;

4. Evaluate each of the following and write the answer to the appropriate number of significant figures.

a) 212.201 + 26.7 + 402.09 =

b) 1.00028 + 0.221 + 0.10337 =

c) 5.43 X 6.7 ÷ 2 =

d) (10.567 - 3.23 – 1.1) X 0.0005 =

5. Convert the following:

a.   8.43 cm =

b.  1.445 X 10⁴ m =

c.   903.3 DL =

6. A recipe for making pasta calls for 0.75 L of cream. Your measuring cups only measures in cups. How many cups of cream should you use?

7. A circle has an area of 25 cm². What is the area in m²?

8. Acetone (nail-polish remover has a density of 0.7857g/cm³.
   1. What is the mass in grams of 17.56 mL of acetone?
   2. What is the volume in milliliters of 7.22 g of acetone?

9. Classify each as a pure substance or a mixture. If it is a pure substance is it an element or a compound. If it’s a mixture is it homogenous or heterogeneous.
   1. Pure water- PS-
   2. Italian dressing-
   3. Salt and water-
   4. Helium gas-

10. Determine whether each is a chemical change or a physical change.
    1. Acetone evaporates
    2. Burning of charcoal
    3. Copper metal turns green on exposure to air
    4. Dry ice sublimes

11. A candy bar contains 225 Calories.
    1. How many calories does it contain?
    2. How many joules does it contain?

12. Determine whether the process is endothermic or exothermic?

a.         Ice melts

b. Match burning

13. Convert the following temperatures.

Ans:

a)   -459 °F =

b)   68 °F =

c)   - 25°C =

d)   801°C =

14. An iron nail with a mass of 12g absorbs 15 J of heat. Calculate the temperature change that takes place.