Chemistry Chapter 1

Chemicals Used When Cooking

-Silicon dioxide (glass) -chemically treated water -metal alloy -natural polymers -natural gas -fruits grown with fertilizers and pesticides

Scientific Method

1.Make observations about nature and ask questions about what you observe .2.Propose a hypothesis, which states a possible explanation of the observations. 3.Several experiments may be done to test the hypothesis. 4.When results of the experiments are analyzed, a conclusion is made as to whether the hypothesis may be true or false.

When a positive number and a negative number are added, the smaller number is subtracted from the larger number, and the result has the same sign as the larger number.

12+(−15)=−3

A premature baby has a mass of 2518 g. We can indicate the place values for the number 2518 as follows:

2-thousands 5-hundreds 1-tens 8-ones

4+(−10)−5=

4 ++ 10 +/− −− 5== −11 2 negatives you ADD

When a value is described as a percentage (%), it represents the number of parts of an item in 100 of those items. If the percentage of red balls is 5, it means there are 5 red balls in every 100 balls. If the percentage of green balls is 50, there are 50 green balls in every 100 balls.

5%red balls=5red balls/100balls 50%green balls=50green balls/100balls

silver coin has a mass of 6.407 g. We can indicate the place values for the number 6.407 as follows:

6-ones 4-tenths 0-hundredths 7-thousandths

0.00086

8.6x10(-4)

A bullet found at a crime scene contains 0.925 g of lead. What are the place values for each of the digits in the mass of the lead?

9-tenths 2-hundredths 5-thousandths

Using Positive and Negative Numbers in Calculations

A positive number is any number that is greater than zero and has a positive sign (+). Often the positive sign is understood and not written in front of the number. For example, the number +8 can also be written as 8. A negative number is any number that is less than zero and is written with a negative sign (−). For example, a negative eight is written as −8.

Predict which student will obtain the best exam score. A student who reads the chapter four times. A student who reads the chapter two times and works all the problems at the end of each Section. A student who reads the chapter the night before the exam.

A student who reads the chapter two times and works all the problems at the end of each Section has interacted with the content in the chapter using self-testing to make connections between concepts and practicing retrieving information learned previously.

Standard number

A whole number or decimal 10,000 0.1 -whatever it is that you are converting to scientific notation is a standard number

Which of the following activities should be included in your study plan for learning chemistry?

A. Skipping lectures will not help you to understand the concepts. B. Forming a study group will be helpful for learning chemistry. C. Keeping a problem notebook will help you to understand and organize the concepts. D. Reading the text as an active learner will help you understand and remember the concepts.

ASK YOURSELF QUESTIONS AS YOU READ

Asking yourself questions as you read requires you to interact continually with new material. For example, you might ask yourself how the new material is related to previous material, which helps you make connections. By linking new material with long-term knowledge, you make pathways for retrieving new material.

Toothpaste chemicals

Calcium Carbonate, Sorbitol, Sodium lauryl sulfate, titanium dioxide, triclosan, sodium fluorophosphate, methyl salicylate

length

Distance between two points metric: meter (m) SI unit: meter (m) The centimeter (cm), a smaller unit of length, is commonly used in chemistry and is about equal to the width of your little finger 1 m = 100 cm 1 m = 39.4 in 1 m = 1.09 yd 2.54 cm = 1 in.

Identify each of the following as an observation (O), a hypothesis (H), an experiment (E), or a conclusion (C): A. During your visit to the gym, your trainer records that you ran for 25 minutes on the treadmill .B. Scientific studies show that exercising lowers blood pressure. C. Your doctor thinks that your weight loss is due to increased exercise.

Identify each of the following as an observation (O), a hypothesis (H), an experiment (E), or a conclusion (C): A. During your visit to the gym, your trainer records that you ran for 25 minutes on the treadmill. Observation (O) B. Scientific studies show that exercising lowers blood pressure. Conclusion (C) C. Your doctor thinks that your weight loss is due to increased exercise. Hypothesis (H)

Triclosan

Inhibits bacteria that cause plaque and gum disease

metric system

It is also the common measuring system in all but a few countries in the world

Once a theory is proven it becomes law

Newtons theories is now Newtons Law

STUDY AT A REGULAR PACE RATHER THAN CRAMMING.

Once you have tested yourself, go back in a few days and practice testing and retrieving information again. We do not recall all the information when we first read it. By frequent quizzing and retesting, we identify what we still need to learn. Sleep is also important for strengthening the associations between newly learned information. Lack of sleep may interfere with retrieval of information as well. So staying up all night to cram for your chemistry exam is not a good idea. Success in chemistry is a combined effort to learn new information and then to retrieve that information when you need it for an exam.

Sodium fluorophosphate

Prevents formation of cavities by strengthening tooth enamel with fluoride

DO NOT KEEP REREADING TEXT OR NOTES.

Reading the same material over and over will make that material seem familiar but does not mean that you have learned it. You need to test yourself to find out what you do and do not know.

Standard number 0.000 008 m 100 000 hairs

Scientific Notation 8×10(−6m) 1×10(5hairs)

1.2

Scientific method

Using the Scientific Method

Suppose you visit a friend in her home, and soon after you arrive, you begin to sneeze. •You observe that your friend has a new cat. •You ask yourself why you are sneezing and form a hypothesis that you are allergic to cats. •You perform experiments to test your hypothesis by visiting other friends with cats. •If you sneeze after leaving the other homes with cats, you come to the conclusion that your hypothesis is correct.

Volume

The amount of space an object takes up metric: L (Liter) SI unit: cubic meter (m3) In a laboratory or a hospital, chemists work with metric units of volume that are smaller and more convenient, such as the milliliter (mL) There are 1000 mL in 1 L. 1 L = 1000 mL 1 L = 1.06 qt 946 mL = 1 qt

The Scientific Method

The scientific method is a set of general principles that helps to describe how a scientist thinks.

SELF-TEST BY GIVING YOURSELF QUIZZES.

Using problems in the text or sample exams, practice taking tests frequently.

STUDY DIFFERENT TOPICS IN A CHAPTER AND RELATE THE NEW CONCEPTS TO CONCEPTS YOU KNOW.

We learn material more efficiently by relating it to information we already know. By increasing connections between concepts, we can retrieve information when we need it.

Which of the following contains chemicals? A. sunlight B. fruit C. milk D. breakfast cereal

Which of the following contains chemicals? A. Sunlight is energy given off by the Sun and therefore does not contain chemicals .B. Fruit contains chemicals that have the same composition and properties wherever found. C. Milk contains chemicals that have the same composition and properties wherever found. D. Breakfast cereal contains chemicals that have the same composition and properties wherever found. Therefore, only B. Fruit, C. Milk, and D. Breakfast cereal contain chemicals.

Which of the following activities should you include in your study plan for learning chemistry successfully? -reading the chapter over and over until you think you understand it going to the professor's office hours -self-testing during and after reading each Section -waiting to study until the night before the exam -trying to work the Sample Problem before looking at the Solution -retesting on new information a few days later

Your success in chemistry can be improved by: b. going to the professor's office hours c. self-testing during and after reading each Section e. trying to work the Sample Problem before looking at the Solution f. retesting on new information a few days later

the significant figures (SFs)

are all the digits including the estimated digit. Significant figures are •used to represent the amount of error associated with a measurement •all nonzero digits and zeros between digits •not zeros that act as placeholders before digits zeros at the end of a decimal number

Measured numbers

are the numbers obtained when you measure a quantity such as your height, weight, or temperature.

Which of the following will help you learn chemistry? skipping review sessions working problems as you read a Section staying up all night before an exam reading the assignment before class

b and d

plural

conclusion bc that means its supported by many

We also identify place values such as the tenths place

first place to the right of the decimal point) and the hundredths place (second place to the right of the decimal point).

methyl salicylate

gives toothpaste a pleasant wintergreen flavor -coolnes

Linus Pauling won the Nobel Prize in Chemistry in 1954

he is responsible for 99.9% of structure of DNA and he is associated with vitamin C

The study habits that are not very helpful in retrieval include

highlighting, underlining, reading the chapter many times, memorizing key words, and cramming.

thinks

hypothesis

titanium dioxide

makes toothpaste white and opaque

Temperature

metric: degree Celsius (C) SI unit: kelvin (k) In the metric system, temperature is measured using Celsius temperature. On the Celsius (°C) temperature scale, water freezes at 0 °C and boils at 100 °C, whereas on the Fahrenheit (°F) scale, water freezes at 32 °F and boils at 212 °F. In the SI system, temperature is measured using the Kelvin (K) temperature scale on which the lowest possible temperature is 0 K. A unit on the Kelvin scale is called a kelvin (K) and is not written with a degree sign.

Time

metric: seconds (s) SI unit: seconds (s)

Sorbitol

prevents loss of water and hardening of toothpaste

My study plan for learning chemistry will include the following:

reading the chapter before class going to class reviewing the Learning Goals keeping a problem notebook reading the text working the Test problems as I read each Section answering the Engage questions trying to work the Sample Problem before looking at the Solution working the Practice Problems at the end of each Section and checking answers studying different topics at the same time organizing a study group seeing the professor during office hours reviewing Key Math Skills and Core Chemistry Skills attending review sessions studying as often as I can

Learning something requires us to place new information in our long-term memory, which allows us to remember those ideas for an exam, a process called

retrieval

scientific notation

right to left- positive left to right-negative decimal appears after 1st non zero digit A number written in scientific notation has two parts: a coefficient and a power of 10. For example, the number 2400 is written in scientific notation as 2.4×10(3). The coefficient, 2.4,

Toothpaste has

sand and many other harsh chemicals. It is sweetened to hide chemicals

Before decimal

tens, ones

After decimal

tenths, hundreths

Mass

the amount of matter in an object metric: gram (g) SI unit: kilogram (kg) In the metric system, the unit for mass is the gram (g), which is used for smaller masses. There are 1000 g in 1 kg. One pound (lb) is equal to 454 g. Some relationships between units for mass are 1 kg = 1000 g 1 kg = 2.20 lb 454 g = 1 lb

calcium carbonate

used as an abrasive to remove plaque

sodium lauryl sulfate

used to loosen plaque-detergent

Matter is another word for all substances that make up our world

•Antacid tablets are matter. •Water is matter. •Glass is matter. •Air is matter. -LIGHT IS NOT MATTER

At the end of the chapter there are study aids that complete the chapter, such as

•Chapter Reviews, which provide a summary •Concept Maps, which show connections between important concepts •Key Terms, which are listed with their definitions •Understanding Concepts, which help you visualize concepts •Additional Questions and Problems and Challenge Problems, which provide a means to assess your understanding

What Is Chemistry?

•is the study of composition, structure, properties, and reactions of matter (CRPS) •happens all around you every day-the basis of life Antacid tablets undergo a chemical reaction when dropped in water.-chemicals arranged differently so they react differently

A graph

•represents the relationship between two variables •contains two perpendicular axes •has a horizontal axis or x axis has a vertical axis or yaxis

Chemicals are

•substances that have the same composition and properties wherever found •often substances made by chemists that you use every day Toothpaste is a combination of many chemicals.

Many figures and diagrams use micro-to-macro illustrations

•to depict atomic level of organization •to illustrate the concepts in the text •to allow you to see the world in a microscopic way