Untitled Quiz

Questions and Answers

What is the amount of calcium added to soil called?

Calcium content

Which of the following would be described as an extensive property of matter?

Color

Temperature

Density

Mass (correct)

Which of the following is not a physical change?

Dissolving sugar in water

Boiling water

Burning gasoline in an engine (correct)

Melting ice

During a phase change, a substance undergoes a(n) __________ change.

reversible Signup and view all the answers

What is the phase change called from a solid to a gas?

Sublimation Signup and view all the answers

How does evaporation differ from boiling water?

Lower temperature and only at the surface Signup and view all the answers

What state of matter takes the volume and shape of its container?

Gas Signup and view all the answers

What state of matter has a definite shape and volume?

Solid Signup and view all the answers

What state of matter has a definite volume but an indefinite shape?

Liquid Signup and view all the answers

Which three phase changes are exothermic?

Condensation Signup and view all the answers

The temperature at which a substance freezes is lower than the temperature at which it melts.

False Signup and view all the answers

Which of the following phrases describes a heterogeneous mixture?

Composition varies Signup and view all the answers

Which of the following is the best example of a homogeneous mixture?

Vinegar Signup and view all the answers

Which technique is used to separate homogeneous solutions?

Distillation Signup and view all the answers

Which of these materials is the best example of a heterogeneous mixture?

Sand Signup and view all the answers

Which of the following can be separated with a filter?

Suspensions Signup and view all the answers

Air is a solution.

True Signup and view all the answers

A colloid will reflect light and the particles will settle, or separate.

False Signup and view all the answers

Suspensions have smaller particles than colloids and solutions.

False Signup and view all the answers

Which of these groups of letters could be used as a symbol for a naturally occurring element?

Cm Signup and view all the answers

Which of the following statements does NOT apply to a compound?

It can be separated into components by physical methods. Signup and view all the answers

What is the smallest particle of an element?

Atom Signup and view all the answers

Which of these substances is a compound?

Water Signup and view all the answers

Which of the following is a mixture?

Air Signup and view all the answers

The symbol for the element potassium is __________.

K Signup and view all the answers

Which of the following is a chemical reaction?

Rusting of iron Signup and view all the answers

Which of the following is NOT a possible clue that a chemical change is taking place?

Change of state Signup and view all the answers

During any chemical change, the mass of the products is __________.

Always equal to the mass of the reactants Signup and view all the answers

The substances formed in a chemical reaction are called products.

True Signup and view all the answers

Carbon dioxide plus water forms carbonic acid. Water and carbonic acid are products of this reaction.

False Signup and view all the answers

What type of change occurs when a puddle dries up in the sun?

Physical Change Signup and view all the answers

What type of change occurs when a dark cloth is faded by the sun?

Chemical Change Signup and view all the answers

What type of change occurs when bread is toasted?

Chemical Change Signup and view all the answers

What type of change occurs when soap is mixed with water?

Physical Change Signup and view all the answers

What type of change occurs when gasoline boils?

Physical Change Signup and view all the answers

What is a mixture?

A physical blend of two or more substances Signup and view all the answers

Define a product in a chemical reaction.

A substance produced in a chemical reaction. Signup and view all the answers

What is a phase in chemistry?

Any part of a sample with uniform composition and properties. Signup and view all the answers

What is distillation?

A process used to separate components of a mixture using differences in boiling points. Signup and view all the answers

What does mass measure?

The amount of matter that an object contains. Signup and view all the answers

What is a chemical reaction?

A change in which one or more reactants change into one or more products. Signup and view all the answers

What is a reactant?

A substance present at the start of a reaction. Signup and view all the answers

Define a heterogeneous mixture.

A mixture that is not uniform in composition. Signup and view all the answers

What is vapor?

The gaseous state of a substance that is usually a liquid or solid at room temperature. Signup and view all the answers

What is a compound?

A substance that contains two or more elements chemically combined in a fixed proportion. Signup and view all the answers

Define an element.

The simplest form of matter that has a unique set of properties. Signup and view all the answers

What is a homogeneous mixture?

A mixture that is uniform in composition. Signup and view all the answers

Matter is anything that has ____ and occupies space.

mass Signup and view all the answers

What type of chemist determines the composition of a moon rock?

Analytical Chemist Signup and view all the answers

What is the difference between a hypothesis and a theory?

A hypothesis is a proposed explanation; a theory is a well-tested explanation. Signup and view all the answers

Organic chemistry is the study of chemicals that contain oxygen.

False Signup and view all the answers

Biochemistry involves the study of living organisms.

True Signup and view all the answers

Pesticides can kill beneficial insects such as bees.

True Signup and view all the answers

Low levels of lead in the blood can permanently damage the nervous system.

True Signup and view all the answers

Macroscopic objects can be seen only under magnification.

False Signup and view all the answers

What type of chemist would develop a new type of wheat seed?

Biochemist Signup and view all the answers

The manipulated variable in an experiment is also known as the ____ variable.

independent Signup and view all the answers

List the steps of solving numeric problems.

Analyze, Calculate, Evaluate. Signup and view all the answers

Study Notes

Mixtures

Mixture: a physical blend of two or more substances; not chemically combined.
Heterogeneous Mixtures: composition is not uniform, components are unevenly distributed (e.g., chicken noodle soup).
Homogeneous Mixtures: uniform composition, components evenly distributed; also known as solutions (e.g., vinegar, air).

Products and Reactants

Product: substance produced in a chemical reaction (e.g., carbon dioxide from burning charcoal).
Reactant: substance present at the start of a reaction (e.g., carbon and oxygen in combustion).

Phases and Distillation

Phase: part of a sample with uniform composition; homogeneous mixtures have one phase, while heterogeneous mixtures have multiple phases (e.g., oil and vinegar).
Distillation: a separation process based on boiling points; it separates water from dissolved substances by producing vapor that is condensed back into liquid.

Mass and Chemical Reactions

Mass: measure of matter in an object; SI unit is kilogram; extensive property meaning it depends on sample size.
Chemical Reaction: a process where reactants are transformed into products, involving bond breaking and forming.

Elements and Compounds

Element: simplest form of matter, unique properties; cannot be broken down chemically (e.g., oxygen, hydrogen).
Compound: substance made of two or more elements chemically combined in fixed proportions (e.g., sucrose).

Scientific Method

Steps of the scientific method include observations, hypothesis testing, experiments, developing theories, and forming scientific laws.
Independent variable: manipulated variable during an experiment; dependent variable: observed variable; controlled variables remain constant.

Importance of Collaboration

Collaboration and communication among scientists enhance problem-solving and knowledge exchange, crucial for complex research.

Hypothesis vs. Theory

Hypothesis: proposed explanation for a limited set of observations; not yet tested.
Theory: well-tested explanation for a broad range of observations.

Solving Numeric Problems

Steps for numeric problem solving: analyze knowns/unknowns, calculate based on a plan, evaluate the reasonableness of the result.

States of Matter

Solid: definite shape and volume, closely packed molecules.
Liquid: indefinite shape, definite volume; molecules are farther apart and flow.
Gas: indefinite shape and volume, easily compressed; molecules are very far apart, move rapidly.

Physical and Chemical Changes

Physical Change: alters some properties without changing composition; examples include slicing bread and evaporation.
Chemical Change: results in new substances with different compositions; examples include burning and rusting.

Signs of a Chemical Reaction

Indicators include energy transfer (heat/light), color change, gas production, and solid formation (precipitate) without heating.

Heat Changes in Phase Transitions

Endothermic changes (heat absorbed): vaporization, melting, sublimation.
Exothermic changes (heat released): condensation, freezing, deposition.

Misconceptions in Chemistry

Organic chemistry studies carbon-containing compounds, not oxygen.
The goal of applied chemistry is to solve problems, not just accumulate knowledge.
Biochemistry focuses on living organisms and their chemical processes.

Chemists and Their Specializations

Analytical Chemists: analyze compositions (e.g., moon rocks).
Physical Chemists: study reaction rates and energy transfer (e.g., gasoline burning).
Biochemists: develop biological applications (e.g., new wheat seed).

Miscellaneous Facts

Low lead exposure can permanently harm the nervous system.
Only microscopic objects require magnification to be seen.
Fossil fuels refer to harmful pollutants, not lead.

Characteristics of Substances

Matter: anything with mass and occupying space.
Homogeneous solutions can be separated via distillation; heterogeneous mixtures can often be separated using filtration.

Reaction Characteristics and Phase Changes

Heterogeneous mixtures show variable composition; examples include sand and suspensions that can be separated by filters.
Common examples of phase changes include sublimation (solid to gas) and exothermic phase changes: freezing, condensation, and deposition.### Suspensions and Particles
False: Suspensions contain larger particles than colloids and solutions.
In suspensions, particles do not settle over time, contrary to the false notion.

Chemical Symbols

Symbol for a naturally occurring element: Cm (Curium).
The symbol for potassium is K.

Compounds and Mixtures

A compound cannot be separated into its components by physical methods.
Water is an example of a compound.
Air is classified as a mixture.

Chemical Reactions

The smallest particle of an element is an atom.
Rusting of iron is an example of a chemical reaction.
Clues indicating a chemical change do not include a change of state.

Mass Conservation

During a chemical change, the mass of the products equals the mass of the reactants.

Products of Reactions

Substances formed in a chemical reaction are termed products.
In the reaction of carbon dioxide plus water to form carbonic acid, water is a reactant, not a product.

Physical and Chemical Changes

A puddle drying in the sun is considered a physical change.
Fading of dark cloth by sunlight, toasting bread, and mixing soap with water are examples of both chemical and physical changes depending on the process.
Boiling gasoline is classified as a physical change.

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