Intro to Chem Exam 1

You go out to dinner and the bill comes to $43.62. How much should you tip if you want the tip to be 20.0 % of the bill?

$8.72

A bag of gumdrops contains 16 orange gumdrops, 8 yellow gumdrops, and 15 black gumdrops. 1. What is the percent of yellow gumdrops? 2. What is the percent of black gumdrops?

1. 21% 2. 38%

In order to test a hypothesis, what should the order of the following steps be? - Analyze data - Confirm or revise the experiment - Collect data - Design an experiment

1. Design an experiment 2. Collect Data 3. Analyze Data 4. Confirm or revise the experiment

Do the following contain chemicals, are chemical reactions, or neither? 1. Heat 2. Neutralization 3. Limestones 4. Combustion 5. Rusting 6. Rainbow 7. Photosynthesis 8. Protein 9. Avocado 10. Sunlight 11. Vitamin E

1. Neither 2. Chemical reaction 3. Contain chemicals 4. Chemical reaction 5. Chemical reaction 6. Neither 7. Chemical reaction 8. Contain chemicals 9. Contain chemicals 10. Neither 11. Contain chemicals

The scientific method is made up of four basic steps: 1. Make an ______, which leads to a _______. 2. Propose a _______, which attempts to explain the _______. 3. Conduct an _______, which tests the _______. 4. Make a _______ about the hypothesis, based on the ______ of your experiment.

1. Observation, question 2. Hypothesis, observation 3. Experiment, hypothesis 4. Conclusion, results

Significant Vs. Not Significant 1. All nonzero digits 2. Trailing zeros when a decimal point is shown 3. Trailing zeros when no decimal point is shown. 4. Showing the decimal point indicates that the preceding zeros are ______ 5. Zeros between nonzero digits 6. Leading zeros

1. Significant 2. Significant 3. Not significant 4. Significant 5. Significant 6. Not significant

You have 125 g of a certain seasoning and are told that it contains 18.0 g of salt. What is the percentage of salt by mass in this seasoning?

14.4% mass

2a+4=40

18 1. Take away 4 from both sides 2. Divide by 2 on both sides

A collection of coins contains 12 nickels, 7 quarters, and 8 dimes. What is the percent of dimes in the collection? Express your answer to the ones place.

30% 1. 12+7+8 = 27 2. 8x100/27 = 30%

Consider the numbers 0, 10, 20, 30, and 40. Multiply each by 4 and compare the result to 60 to determine into which of the following intervals the answer to the question "What number can you multiply by 4 and then add 8 to the product to get 60?" should fall. Select the interval into which the answer should fall: A. 0 to 10 B. 10 to 20 C. 20 to 30 D. 30 to 40

4x+8=60? B. 10-20 4x+8=60 1. Divide by 4 on each side (60/4 = 15) 2. Subtract 8 from each side (15-8 = 7) 3. x=7

What does scientific notation look like?

5.05x10^3

What does standard notation look like?

5050

An alloy contains 52 g of pure silver and 19 g of pure copper. What is the percent silver in the alloy? Express your answer to the ones place.

73% 1. 52+19 = 71 2. 52x100/71 = 73%

A test has 25 questions. If a student has 20 answers correct, what percent of the questions was correct? Express your answer to the ones place.

80%

In a college of exactly 2860 students, exactly 70 % are male. What is the number of female students?

858 students are female

After the exam has been completed, you have the students anonymously fill out a questionnaire asking about their study habits for the exam and the grade they earned on the exam. From the surveys, you randomly select 10 students who studied for the exam and 10 students who did not study for the exam. You create the table showing the students' exam grades given here: 10 students who studied: 93 96 90 87 89 99 78 96 97 95 10 students who did not study: 65 72 71 64 55 49 88 67 76 63 What was the average exam grade for each set of students? Enter the average exam grade of students who studied, followed by the average exam grade of the students who did not study, using two significant figures, separated by a comma.

92,67 Add all 10 scores, and divide by the number of students, in this case 10.

Experiment

A procedure that tests the validity of a hypothesis

Which of the following experiment setups would be the best way to test your hypothesis? A. After the exam, give students a survey questioning their study habits and what grade they made on their exam. B. Before the exam, give students a survey questioning their study habits. C. After the exam, give students a survey questioning their study habits and what grade they think they made on the exam. D. Before the exam, give students a survey questioning their study habits and what grade they think they will make on the exam.

A. After the exam, give students a survey questioning their study habits and what grade they made on their exam.

Recall that the equation 4x+8=60 was restated in words as, "What number multiplied by 4 and then added to 8 gives 60?" Which of the following would be an equivalent way to write this? A. What number can you multiply by 4 to get a number 8 less than 60? B. What number can you subtract 60 from and then divide by 4 to get 8? C. What number can you multiply by 4 to get a number 8 larger than 60? D. What number can you divide by 4 to get a number 8 less than 60?

A. What number can you multiply by 4 to get a number 8 less than 60?

Theory

An explanation of an observation that has been validated by repeated experiments that support a hypothesis

Hypothesis

An unverified explanation of a natural phenomenon

In multiplication or division, the result carries the same number of significant figures as the factor with the ______ significant figures.

Fewest

Observation

Information determined by nothing and recording a natural phenomenon

When dealing with scientific notation, a negative exponent shows that the decimal point is shifted that number of places to the ______.

Left

A chemical is...

Made of particles with a measurable mass.

When dealing with scientific notation, a positive exponent shows that the decimal point is shifted that number of places to the ______.

Right

A general term for a chemical is a(n) __________.

Substance

Scientific method

The process of making observations, proposing a hypothesis, testing the hypothesis, and developing a theory that explains a natural event

Chemistry

The study of the composition, structure, properties, and reactions of matter

You know that a number 8 less than 60 is the number 52. So, you could rewrite your answer from the previous part as, "What number can you multiply by 4 to get 52?" This is just the definition of 52 divided by 4! So, what is the number x you are looking for?

x=13