Chem B11: Intro to General, Organic, and Biochemistry

Exam 1 (Ch 1-4) Study Guide

Chemistry

Is the science that seeks to understand what matter does by studying what atoms and molecules do.

What is Chemistry the study of?

Is the study of composition, structure, properties, and reactions.

Matter

Is anything that has mass and volume

Atoms

The fundamental building blocks of all matter.

Molecules

Are made of 2 or more atoms attached via chemical bonds.

The Scientific Method

Is a way of learning that emphasizes using to the senses produce knowledge through observations and experiments.

True or False: The Scientific method is a set of general principles that helps to describe how a scientist thinks.

True

Observation

Involve measuring or observing some aspect of nature.

Laws

Are summaries of the results of a large number of observations.

Hypotheses

Are tentative interpretations of the observations.

Experiments

Are highly controlled procedures designed to validate or invalidate hypotheses.

Theories

Are models that explain and give the underlying causes for observations and laws

Example) A blender doesn’t work when plugged in.

What scientific method is being used?

Observation

Example) The blender motor is broken.

What scientific method is being used?

Hypothesis

Example) The blender does not work when plugged into different outlets.

What scientific method is being used?

Experiment

Example) The blender needs repair.

What scientific method is being used?

Theory

Scientific Notation

Is a way of writing very large and very small numbers

The number 98000 written in scientific notation would be?

9.8 × 10⁴

The number 0.000008706 written in scientific notation would be?

8.706\cdot10^{-6}

Significant Figures

Is the system we use to write measurements.

How many Significant Figures does the number 1.006 × 10⁷ have?

4

How many Significant Figures does the number 23.070 have?

5

How many Significant Figures does the number 0.054901 have?

5

How many Significant Figures does 100 cm/m have?

Unlimited

How many Significant Figures does 10,000 kg have?

1

How many Significant Figures does 1 dozen = 12 have?

Unlimited

How many Significant Figures does the number 0.0035 have?

2

How many Significant Figures does 100 pens have?

Unlimited

How many Significant Figures does the number 120400 have?

4

How many Significant Figures does the number 130. have?

3

Accuracy

How close a measurement is to the accepted value.

Precision

How close a series of measurements are to each other.

16.84

Complete the operation: 5.74 + 0.823 + 2.6 =

Use the correct number of Significant Figures.

Answers:

A) 9.163

B) 9.160

C) 9.2

D) 9.1

C

Complete the operation: 1624 + 52.8 + 121.23 - 6.459 =

Use the correct number of Significant Figures.

Answers:

A) 1792

B) 1790

C) 1791.571

D) 1791.57

A

What is the answer for : 3.489 × ( 5.68 - 2.3 ) =

a) 11.79

b) 11.8

c) 12

d) 11.79282

C

tera-

Symbol: T

Meaning: trillion

(10¹²⁾

giga-

Symbol: G

Meaning: billion

(10⁹)

mega-

Symbol: M

Meaning: million

(10⁶)

kilo-

Symbol: k

Meaning: thousand

(10³)

deci-

Symbol: d

Meaning: tenth

(10^-1)

centi-

Symbol: c

Meaning: hundredth

(10^-2)

milli-

Symbol: m

Meaning: thousandth

(10^-3)

micro-

Symbol: μ

Meaning: millionth

(10^-6)

nano-

Symbol: n

Meaning: billionth

(10^-9)

Kelvin

Absolute scale

Celsius

Used in other countries

Fahrenheit

Used in the United States

Equation: Density

Density= Mass/Volume

Equation: Mass

Mass= Density x Volume

Equation: Volume

Volume= Mass/Density

Question: For a liquid substance with a density of 1.32 g/cm^3, what volume should be measured to deliver a mass of 68.4 g?

51.8\operatorname{cm}^3

Dimensional Analysis

Is a system that uses units as a guide to problem solving.

Question: Convert 25.3 in^3 to m^3? ( 1 in = 2.54 cm )^3 and ( 1 m = 100 cm )^3

A) 3.72 × 10^-4 m^3

B) 4.15 × 10^-4 m^3

C) 9.23 × 10^-4 m^3

D) 6.20 × 10-1 m^3

E) 1.87 × 10^-2 m^3

B

Question: A blood sample of 5.36 milliliters is collected from a patient to be analyzed for a platelet count. Human blood should have around 1.04 kg/L platelets. What is the expected mass in grams of platelets in the blood sample?

A) 6 g of platelets

B) 5.5744 g of platelets

C) 5.57 g of platelets

D) 5.574 g of platelets

C

Pure Element

Are the substances that cannot be broken down to simpler substances by chemical reactions.

Pure Compound

Are substances composed of 2 or more different types of atoms in fixed proportions.

Mixtures

Are composed of two or more different types of atoms that are not chemically bonded but simply physically mixed.

Homogeneous mixture

Is a mixture that has a uniform composition.

Heterogeneous mixture

Is a mixture that does not have a uniform composition.

Question: Classify the following as homogeneous or heterogeneous

Salt Water

Homogeneous

Question: Classify the following as homogeneous or heterogeneous

A mixture of table sugar and black pepper

Heterogeneous

Question: Classify the following as homogeneous or heterogeneous

Oil and vinegar salad dressing

Heterogeneous

Question: Classify the following as homogeneous or heterogeneous

Shampoo

Homogeneous

Question: Classify the following as homogeneous or heterogeneous

Peach pie

Heterogeneous

Compounds

Can only be separated into its components (elements) by chemical means (a chemical reaction).

Distillation

Separates components of a mixture according to their boiling points.

Filtration

Separates components of a mixture according to their physical state.

Question: Classify the following as pure substance or mixture

Air

Mixture

Question: Classify the following as pure substance or mixture

Helium

Pure substance

Question: Classify the following as pure substance or mixture

Blood

Mixture

Question: Classify the following as pure substance or mixture

Aluminum Foil

Pure substance

Question: Classify the following as pure substance or mixture

A 14 karat gold ring

Mixture

Solid

Atoms and molecules are packed close together and fixed in position.

Liquid

Atoms and molecules are closely packed, but they have some ability to move around.

Gas

Atoms and molecules are far apart from each other.

Properties of matter

1. Intensive Properties

2. Extensive Properties

3. Physical Property

4. Chemical Property

Intensive Properties

Independent of sample size.

( Ex: Density, Melting point, Boiling point, color, etc.)

Extensive Properties

Dependent of sample size.

(Ex: Mass, Volume, Energy, etc.)

Physical Property

Is a characteristic that a substance displays without changing its composition.

(Ex: Color, shape, taste, smell, m/b points, mass, electricity, malleability, and heat conduction.)

Chemical Property

Is a characteristic that a substance displays only through changing its composition.

(Ex: Acidity, basicity, oxidation (rusting of iron), combustion (burning coal).

Physical change

Are changes that alter the state or appearances of matter without altering its composition.

1. Change in the state of matter (solid, liquid, gas).

2. Change in the physical shape.

(Ex: Boiling water, sugar dissolving in coffee, seawater evaporating).

Chemical change

Are those changes that alter the composition of matter.

1. Results in a new composition.

2. Results in a new chemical and physical properties.

(Ex: Burning oxygen, rusting of iron)

Question: Classify the following change as physical or chemical

An egg splitting open and spilling out

Physical

Question: Classify the following change as physical or chemical

Sugar fermenting

Chemical

Question: Classify the following change as physical or chemical

Bubbles escaping from soda

Physical

Question: Classify the following change as physical or chemical

Bubbles that form when hydrogen peroxide is mixed with blood

Chemical

Question: Classify the following change as physical or chemical

Evaporation of rubbing alcohol

Physical

Question: Classify the following change as physical or chemical

Sugar turning black when heated

Chemical

Energy

Is the capacity to do work or transfer heat.

Kinetic Energy

Is the energy associated with motion.

(Ex: Swimming, Working out, Water flowing over a dam).

Potential Energy

Is the energy that is stored energy due to position of an object or its composition.

(Ex: A compressed spring, chemical bonds in food, water at the top of a dam)

Question: Identify the energy as potential or kinetic

Gasoline in the gas tank

Potential

Question: Identify the energy as potential or kinetic

A peanut butter and jelly sandwich

Potential

Question: Identify the energy as potential or kinetic

Mowing the lawn

Kinetic

Temperature

Is a measure of the thermal energy of a substance (not the exchange of thermal energy.)

Law of Conservation of Matter

Matter is neither created nor destroyed in a chemical reaction.

Law of Conservation of Energy

Energy is neither created nor destroyed by can change from from one form to another.

Exothermic

Are those reactions that result in the release of Energy.

1. Reactants have less potential energy than products

2. Exothermic=heat

Endothermic

Are those reactions that result in the absorption of Energy.

1. Products have more potential energy than reactants.

2. Endothermic=cold