LUOA Chemistry: Test 1

Convert the following number to standard notation: 5.32 x 10-8 Remember to insert commas and decimals as needed.

.0000000532

Divide the following: (8.1 x 10-2) ÷÷ (9.0 x 102) Remember to insert commas and decimals as needed.

.00009

Solve the following math problem and report your answer using the correct number of significant figures. 2.614/12.4

.210

Divide the following: (7.8×103)÷(1.2×104)(7.8×103)÷(1.2×104) Remember to insert commas and decimals as needed.

.65

Solve the following math problem and report your answer using the correct number of significant figures. 1.81/2.1132

.857

Convert: 57 cm = _____ km

0.00057 km

How many cm are there in 1.23 x 10-6 km?

0.123 cm

Please solve this problem using dimensional analysis. Show your work below. To earn full credit, work must be shown. How many nanoliters are in 1 liter?

1 x 10^9 = 1,000,000,000 1 x 10^9

Solve the following problem: How many seconds are in 3 years? Please show your work. You will need to include the following conversion factors: 365 days/1 yr or 1 yr/365 days 1 day/24 hours or 24 hours/1 day 60 min/1 hour or 1 hour/60 min 1 min/60 sec or 60 sec/1 min

1 x 365/1 x 24/1 x 60/1 x 60/1 = 31,536,000/1 3.1535 x 10^7 (x 3)

Multiply the following: (4.3×108)×(2.8×102)(4.3×108)×(2.8×102) Remember to insert commas and decimals as needed.

1.2 x 1011

In the question, "How many cm are in 100 inches? (1 inch = 2.54 cm)," what is your starting point?

100 inches

Indicate the number of significant figures in the following measured number: 0.0020

2

Please solve this problem using dimensional analysis. Show your work below. To earn full credit, work must be shown. How many meters are in 2 gigameters?

2 x 10^9 = 2,000,000,000 2 x 10^9

Convert: 2390 mg to g

2.39 g

Convert: 2390 g to kg

2.39 kg

Convert: 0.250 kg = _____ mg

250,000 mg

12.5 / 12.5 pts Indicate the number of significant figures in the following measured number: 0.508

3

Match the calculation with the correct answer.

3.03 x 54.1 164 20.50 x 8.000 164.0 22.1 x .00114 0.0252 .2270 x .1110 0.02520 52.910 x .021 1.1 .277 x 4.01 1.11

How many km are there in 3.34 x 105 cm?

3.34 km

Multiply the following: (6.2×103)×(5.8×10−4)(6.2×103)×(5.8×10−4) Remember to insert commas and decimals as needed.

3.596

Solve the following math problem and report your answer using the correct number of significant figures. 15.2+16.215+2.2+2.77139

36.4

Indicate the number of significant figures in the following measured number: 30.08

4

Write the following number in scientific notation: 56,000,000

5.6 x 107

Solve the following math problem and report your answer using the correct number of significant figures. 12.45/2.1

5.9

Indicate the number of significant figures in the following measured number: 809.080

6

Convert: 65 kg to mg

65,000,000 mg

Convert the following number to standard notation: 7.68 x 103 Remember to insert commas and decimals as needed.

7,680

Convert: 8700 mL = _____ L

8.7 L

Types of Chemistry

Analytical Chemistry This field of chemistry is the science of obtaining and communicating information about the composition of matter. Analytical Chemists use their knowledge to solve problems in almost all areas of chemistry. Biological Chemistry This explores chemical processes in living organisms. Biochemists interact with other scientists on small problems that are part of a complex system. Inorganic Chemistry This is concerned with the properties of inorganic compounds. Inorganic Chemists' work is based on understanding of inorganic elements and the materials can be used. Physical Chemistry This deals with physics involved in chemical reactions. Physical Chemists try to understand compounds by using mathematical analytics and statistics. Organic Chemistry This is the study of carbon containing compounds. Organic Chemists create and explore molecules and compounds.

Describe two ways chemistry has benefited humankind. Please use complete sentences.

Chemistry has benifited humankind by allowing us to understand how to make different medecines, and also better products such as plastics.

In the graph below, what is the dependent variable?

Concentration

The measured value is also known as the ___________ value.

Experimental

A researcher mixes 10 grams of sodium hydroxide in a 100-ml flask, with different amounts of hydrochloric acid, to study the pH of the solution. The independent variable is ___________.

Hydrochloric acid

Using complete sentences, explain how a set of experimental data can be: a. Accurate, but not precise b. Precise, but not accurate c. Neither accurate nor precise Please do not use the target ideas from the lesson. Your explanations should be original.

If a set of experimental data is accurate, but not precise, that means that the answers recieved are not close to each other, but are all very close to the correct answer. If a set of experimental data is precise, but not accurate, that means that all the answers recieved are very close to one another but are not close to the correct answer. If a set of experimental data is neither accurate nor precise, that means that the answers recieved are neither close to one another or the correct answer.

What type of relationship is seen in the graph below?

Inverse relationship

Items that can be seen, touched, and measured directly can be described as ___________.

Macroscopic

Chemistry is the study of ___________ and the changes it undergoes.

Matter

Items that cannot be seen with the human eye can be described as ___________.

Microscopic

Explain in 2-3 sentences why scientists use scientific notation.

Scientists will use scientific notation because the numbers they use are usually very big or very small. Scientific notation helps make the number easier to write down and read.

Matter is anything that has mass and takes up ___________.

Space

The actual value is also known as the ___________ value.

Theoretical

In the graph below, what is the independent variable?

Time

A student calculates the volume of a graduated cylinder to be 43.26 ml. The actual volume is 42.32 ml. What is the percent error? Show your work below. Round your answer to two digits.

[43.26 - 42.32] / 42.32 x 100 .94 / 42.32 x 100 2.2 The percent error is 2.2%

The experimental mass is 51.5 grams and the theoretical mass is 50 grams. What is the percent error? Show your work below. Round your answer to two digits.

[51.5 - 50] / 50 x 100 1.5 / 50 x 100 3 The percent error is 3%

A student calculates the mass of a piece of copper to be 8.3 grams. The actual mass of the copper is 10 grams. What is the percent error? Show your work below. Round your answer to two digits.

[8.3 - 10] / 10 x 100 1.7 / 10 x 100 17 The percent error is 17%

In the question, "How many cm are in 100 inches? (1 inch = 2.54 cm)," what is your unit ending point?

cm

A researcher mixes 10 grams of sodium hydroxide in a 100-ml flask, with different amounts of hydrochloric acid, to study the pH of the solution. The dependent variable is ___________.

pH