Chemistry of Life Flashcards Chapter 2

Questions and Answers

If an atom contains 3 protons, 4 neutrons, and 3 electrons, what is its mass number?

If an atom contains 11 protons and 12 neutrons, what is its atomic number?

What is a molecule of water made up of?

Two atoms of hydrogen and one atom of oxygen

How is a covalent bond formed?

By sharing electrons Signup and view all the answers

Why are water molecules polar?

Because the oxygen side is slightly negative and the hydrogen side is slightly positive Signup and view all the answers

What do you produce when you stir salt into boiling water?

A solution Signup and view all the answers

What is a substance with a pH of 6 called?

An acid Signup and view all the answers

What are solutions that have more OH- than H+ ions called?

Bases Signup and view all the answers

Why is carbon considered special compared to other elements?

Because carbon atoms can bond to one another and form a lot of different structures Signup and view all the answers

How many covalent bonds can a carbon atom form?

4 Signup and view all the answers

Match the following substances with their corresponding pairs:

Amino acid = Protein Simple sugar = Starch Signup and view all the answers

What happens to atoms in chemical reactions?

They are rearranged Signup and view all the answers

When hydrogen atoms and oxygen atoms combine to form water, what is water considered?

A product Signup and view all the answers

What are enzymes?

Proteins that work best at a specified pH and have a shape that allows them to perform their function Signup and view all the answers

Which subatomic particles are most involved in forming chemical bonds?

Electrons Signup and view all the answers

Why is a water molecule polar?

There is an uneven distribution of electrons between the oxygen and hydrogen atoms Signup and view all the answers

Match complex carbohydrates with their simple units:

Complex carbohydrates = Monosaccharides Polymers = Monomers Signup and view all the answers

What are the elements or compounds that go into a chemical reaction called?

Reactants Signup and view all the answers

What is the energy needed to start a chemical reaction?

The activation energy Signup and view all the answers

Can you predict the properties of a compound by knowing the properties of the elements that make up the compound?

False Signup and view all the answers

How does a sodium atom form a bond with a chlorine atom?

The sodium atom loses an electron and becomes positively charged; the chlorine atom gains an electron and becomes negatively charged, forming an ionic bond Signup and view all the answers

What happens to atoms when H2 gas and O2 gas react to form water, and what kind of bonds result?

The atoms are rearranged into water molecules, and covalent bonds are formed between H and O atoms Signup and view all the answers

What accounts for water's properties of adhesion and cohesion?

Cohesion holds hydrogen bonds together to create surface tension, while adhesion pulls water toward other molecules Signup and view all the answers

What is a mixture?

A material composed of two or more elements or compounds that are physically mixed together but not chemically combined Signup and view all the answers

What relationship exists between the mass number of an element and its isotopes?

Isotopes of an element have the same number of protons but different numbers of neutrons, resulting in different mass numbers Signup and view all the answers

When comparing tomato juice with a pH of 4 and soap with a pH of 10, what would you find regarding their acidity?

Tomato juice is acidic because it has a pH less than 7; soap is basic because it has a pH of more than 7 Signup and view all the answers

How can you account for the great number, size, and complexity of organic compounds?

All organic compounds have the element carbon that needs to share 4 valence electrons Signup and view all the answers

Study Notes

Atomic Structure

An atom's mass number is the sum of protons and neutrons; example: 3 protons and 4 neutrons give a mass number of 7.
Atomic number reflects the number of protons; an atom with 11 protons has an atomic number of 11.

Molecular Composition

Water consists of two hydrogen atoms and one oxygen atom, forming H2O.
Covalent bonds are created when atoms share electrons.

Properties of Water

Water molecules are polar, with the oxygen side being slightly negative and the hydrogen side slightly positive.
The uneven distribution of electrons between oxygen and hydrogen creates the polar nature of water, leading to properties like adhesion and cohesion.

Solutions and pH

Stirring salt into boiling water produces a solution, which is a homogeneous mixture.
A substance with a pH of 6 is classified as an acid, while solutions with more OH- than H+ ions are considered bases.
Tomato juice (pH 4) is acidic, and soap (pH 10) is basic; pH comparison indicates acid or base properties.

Organic Chemistry

Carbon is unique due to its ability to form multiple bonds with itself and other elements, allowing various complex structures.
Carbon-12, the most abundant isotope, has 6 protons, 6 neutrons, and 4 valence electrons, enabling it to form 4 covalent bonds.

Biological Macromolecules

Amino acids are the building blocks of proteins, similar to how simple sugars serve as the foundation for starches.
Complex carbohydrates consist of monosaccharides, just as polymers are composed of monomers.

Chemical Reactions

In chemical reactions, atoms undergo rearrangement, transforming reactants into products such as water from hydrogen and oxygen.
The activation energy is the necessary energy to initiate a chemical reaction.

Chemical Bonding

Sodium forms an ionic bond with chlorine by losing an electron to become positively charged, while chlorine gains an electron to become negatively charged, resulting in ion attraction.
When hydrogen and oxygen gases react, they rearrange into water molecules, forming covalent bonds between atoms.

Mixtures and Compounds

Mixtures consist of two or more substances physically combined without chemical bonding, contrasting with pure compounds.
Isotopes of an element share the same number of protons but differ in neutron count, resulting in varied mass numbers.

Laboratory Observations

Organic compounds are numerous and complex due to carbon's ability to form diverse structures with multiple bonding possibilities.
Enzymes work most effectively at specific pH levels and are proteins whose shape is crucial for function.

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Test your knowledge with these flashcards based on Chapter 2: The Chemistry of Life. Cover essential topics like atomic structure, molecular composition, and bond formation. Perfect for students looking to reinforce their understanding of chemistry concepts.