Organic and Biochemical Compounds/ Simple Organic Compounds/ Properties of Matter/ Changes of Matter

Calculate the density of a sample of liquid with a volume of 130 ml and a mass of 585 g.

4.5 g/ml

What is the boiling point of oxygen?

-183 degrees C

Hydrogen is a liquid below what temperature?

-253 degrees C

Calculate the density of a sample of gas with a mass of 30 g and volume of 7500 cm3.

0.004 g/cm^3

The boiling point of a substance is a chemical property

False

The weight of a substance is defined as its mass divided by its volume

False

A very flammable substance would not be used in children's clothing.

True

The chemical properties of a substance can only be observed when it is changed into a different substance.

True

What is the minimum number of carbon atoms an unsaturated hydrocarbon can have? Explain.

Two; an unsaturated hydrocarbon has a double or triple bond between carbon atoms.

A liquid changes rapidly into a gas at the liquid's

boiling point.

Calculate the mass of a gas with a density of 0.0065 g/cm3 and volume of 260 cm3.

1.69 g

A substance has a mass of 360 g and a volume of 7.5 cm3. What is its density?

48 g/cm^3

Calculate the volume of a solid with a density of 5.3 g/cm3 and a mass of 371 g.

70 cm^3

Define chemical change.

A change that occurs when a substance changes composition by forming one or more new substances.

A new statue of the town founder is erected in the park. At the unveiling, the statue is a orange-brown copper. After a year, the statue looks blue-green. Has a physical or chemical change taken place?

A chemical change has occurred.

What is a hydrocarbon?

A hydrocarbon is a compound containing only carbon and hydrogen.

What is a hydrocarbon?

A hydrocarbon is a compound that consists of nothing but hydrogen and carbon atoms.

How are characteristic properties of a given substance different from its other properties and chemical properties?

A substance's characteristic properties are the most recognizable properties of that substance.

Is alcohol a hydrocarbon? Justify your answer.

Alcohol is not a hydrocarbon. Hydrocarbons contain only carbon and hydrogen atoms. Alcohols contain oxygen in their hydroxyl groups.

Describe the basic structure of an alkane.

Alkanes are formed from carbon and hydrogen atoms. The carbon atoms of an alkane have four single, covalent bonds that connect them to other carbons or to hydrogens.

What feature characterizes an alkene?

Alkenes are organic compounds that contain carbon-carbon double bonds.

Explain how proteins are formed using the concept of polymerization.

Amino acids are the monomers that join together to form proteins. Proteins are polymers.

How does the structure of ethene compare to the structure of ethane?

Both ethene and ethane contain two carbons. Ethene has a double bond between its two carbons while ethane has a single bond. Because of this, ethane contains six hydrogen atoms, but ethene only contains four.

What is the function of carbohydrates in the body?

Carbohydrates provide energy to the body.

Why does carbon form the basis for so many different kinds of compounds?

Carbon atoms can form covalent bonds with four different atoms at one time. With four possible binding sites, many different compounds can form.

What is cellulose and what does it do?

Cellulose is a carbohydrate that makes up the backbone of plants. It is the structural element in cell walls that helps to give plants their shape.

Adding bleach to red food coloring causes the food coloring to lose its color. Is this a physical or chemical change? Explain.

Chemical change; the bleach and the food coloring react when mixed and the food coloring loses its color, making it a chemical change.

A ______ property describes how a substance acts when it reacts with other substances.

Chemical property

Too much cholesterol is a bad thing, but your body needs some cholesterol to work. What is the function of cholesterol in your body?

Cholesterol helps to make cell membranes.

Describe the structure of DNA.

DNA is a complex polymer. It is composed of two strands that bind together to form a structure that resembles a twisting ladder.

Why is density an important property of matter? Explain at least two ways in which density has practical importance.

Density affects whether something floats in a particular liquid. Boats float because the air inside the vessel is less dense than the water the vessel sits in. Cream can be separated from milk because it is less dense than milk and floats to the top.

Give four reasons for the existence of so many—over eight million—organic compounds.

Each carbon atom can form four bonds. Carbon can form single, double, and triple bonds. Carbon can bond to itself in chains and rings. Carbon compounds can exist as isomers.

Give one chemical and physical property of wood.

Example answer: A physical property of wood is that it has a grainy texture. A chemical property of wood is that it is flammable.

Why are some organic compounds known as saturated hydrocarbons?

Hydrocarbons with only single bonds are called saturated because no more hydrogen molecules can be added to the compound. They are saturated with hydrogen.

How do two isomers differ from one another?

Isomers have the same chemical formula but different structures.

Why is it important to eat a variety of carbohydrates?

It is important to eat both sugars and starches. Sugars will give you quick boosts of energy, but starches are needed for sustained energy.

Why is gold often found in a pure form in nature?

It is relatively non-reactive, a characteristic property of gold.

What is the role for lipids in your body?

Lipids store energy.

Explain why changes of state are physical changes.

Melting, boiling or freezing a substance doesn't affect its chemical properties.

How do molecules in a solid differ from those in a liquid or gas?

Molecules in a solid are relatively fixed in position.

"Organic compounds are the basis for all life." Explain this statement.

Organic compounds are carbon-based compounds such as sugars, starches, alcohols, and proteins. Our bodies are made of different proteins, and sugars give us energy. Our DNA is also a type of organic compound called a polymer.

Is crumpling a sheet of paper a physical or chemical change? Why?

Physical change; the chemical properties of paper remain unchanged.

Describe how physical and chemical changes are different. How are they similar?

Physical changes are different from chemical changes in that after a chemical change, a new substance is formed. This is not true of physical changes. They are similar in that both types of change involve energy and the substance that undergoes the change may look differently afterward.

What is polymerization?

Polymerization is the joining of monomers into long chains that form a larger molecule called a polymer.

Plucking a guitar string is a physical change; however, the process produces sound. Explain.

Possible answer: The sound production is a physical property of the guitar string. Producing it does not affect the string's chemical properties.

List four clues that suggest a chemical change is taking place, and provide an example for each.

Possible answers: heat, sound, or gas production, and odor or color change. Examples include burning wood, cooking food, and clothing losing color after being bleached.

Why is protein classified as a polymer?

Proteins are classified as polymers because they are long chains of amino acids bonded together.

Discuss three important functions of proteins in the body.

Proteins have many important functions in the body. They act as catalysts in many of the reactions in cells. They make up the structure of the body: skin, bones, hair, etc. Hemoglobin, the substance the carries oxygen to the cells, is a protein.

Why is a balanced diet important for good health?

Proteins, carbohydrates, and lipids serve different important functions in the body.

Explain the difference between saturated and unsaturated hydrocarbons.

Saturated hydrocarbons contain only single bonds, but unsaturated hydrocarbons will also have double and triple bonds.

Explain the differences between saturated and unsaturated lipids and give examples of each.

Saturated lipids have only single bonds, while unsaturated lipids also contain double bonds. Also, saturated lipids tend to be straight and less healthy to eat than unsaturated lipids. Because of their double bonds, unsaturated lipids have bends and kinks. Margarine is an example of a saturated lipid. Olive oil is an example of an unsaturated lipid.

Why are some polymers stretchy while others are not?

The elasticity of a polymer depends on the cross-linking of its chains.

Are C4H10 and C4H8 isomers of each other? Why or why not?

They are not isomers of each other, because they have different molecular formulas. Isomers have the same molecular formula and different structures.

Are hexane and cyclohexane isomers? Why or why not?

They are not isomers. They do not have the same number of hydrogen atoms.

While camping, you accidentally burn your marshmallows. Is this a physical or chemical change? How can you tell?

This is a chemical change. There is a change in color, from white to black. There is also a smell given off. In addition, heat is given off as the marshmallow burns.

A carpenter sands a wooden board until it is smooth. Is this a physical or a chemical change?

This is an example of a physical change.

Organic compounds ____________ (are/are not) only generated by living things.

are not

How is the density of an object calculated?

by dividing the mass of the object by its volume

Tooth fillings are often made of gold or porcelain because these materials are ______.

nonreactive

____________ (Saturated/Unsaturated) hydrocarbons contain only single bonds.

saturated