Unit 2 - Test Study

Question 1

What are the main parts of an atom?

Answer 1

Center is the nucleus made of protons and neutrons. Whizzing around it are electrons in the electron cloud

Question 2

What are the most common elements in living things

Answer 2

Carbon, hydrogen, nitrogen, oxygen, phosphates

Question 3

What is an element

Answer 3

substance made of only on type of atom that cannot be broken down by chemical means

Question 4

What is an ion

Answer 4

atom that has gained of lost one or more electrons

Question 5

What is an ionic bond

Answer 5

Type of chemical bond that is strong in which one atom gives up some electrons and another gains those electrons causing positing and negatively charged atoms that attract each other

Question 6

What is a covalent bond?

Answer 6

Weaker type of bond that results when atoms share electrons

Question 7

Molecule

Answer 7

two or more atoms held together by covalent bonds

Question 8

What is a compound?

Answer 8

substances composed of atoms of two or more different elements bonded together in specific ratios such as CO2 and H2O

Question 9

In CO2 what does the 2 represent

Answer 9

That there are two oxygens per molecule

Question 10

Mixture

Answer 10

a compound of two or more components that are not chemically mixed

Question 11

Solution

Answer 11

a solute dissolved in a solvent

Question 12

Solute

Answer 12

the substance being dissolved

Question 13

solvent

Answer 13

substance that dissolves something else (ie water is a solvent that dissolves sugar)

Question 14

Organic molecules

Answer 14

molecules that contain carbon

Question 15

What is the difference between ionic and covalent bonds

Answer 15

Ionic bonds are when one atom gives up an electron to another and are stronger, while covalent bonds are when an electron is shared and are weaker

Question 16

What are parts of a chemical equation

Answer 16

reactant -> activation energy -> product

Question 17

Explain the properties created by water’s polar molecules

Answer 17

Oxygen attracts the shared hydrogen electrons more strongly, so O part of molecule is more negative. Causes molecules to align and create hydrogen bonds (attraction of other molecules hydrogens to other molecules oxygens). This makes surface tension on water. Without hydrogen bonds, water would boil at lower temperatures, also creates high specific heat, cohesion, adhesion, and ability to dissolve other polar molecules.

Question 18

What is specific heat

Answer 18

Amount of energy required to raise 1g of water 1 degree C. Measure of energy needed to heat something. Water has high specific heat which means it absorbs energy well.

Question 19

What is cohesion

Answer 19

Cohesion from hydrogen bonds makes water molecules “stick” to each other and produces surface tension.

Question 20

What is adhesion

Answer 20

Adhesion The attraction among molecules of different substances is called adhesion. For example, water molecules can stick to each other or to the sides of a glass tube. Adhesion helps plants transport water from their roots to their leaves, because water molecules stick to the sides of the tissues through which water passes.

Question 21

Acids release what in water

Answer 21

H+

Question 22

Bases absorb what?

Answer 22

H+

Question 23

What is a chemical reaction

Answer 23

chemical reaction
process by which substances change into different substances through the breaking and forming of chemical bonds

Question 24

What is the principle of the conservation of matter

Answer 24

conservation of matter. This means that in chemical reactions, atoms are not created or destroyed, only rearranged.

Question 25

Explain the Hydrogen Peroxide Reaction

Answer 25

Hydrogen Peroxide Reaction | This chemical reaction shows that two molecules of hydrogen peroxide (H2O2) break apart to form two molecules of water (H2O) and one molecule of oxygen (O2).

Question 26

What is activation energy

Answer 26

the amount of energy that needs to be absorbed to start, or activate, a chemical reaction.

Question 27

Exothermic reaction

Answer 27

When a chemical reaction releases more energy than it absorbs, it is called an exothermic reaction.

Question 28

Endothermic Reaction

Answer 28

When a chemical reaction absorbs more energy than it releases, it is called an endothermic reaction. In an endothermic reaction, the products have higher bond energies than the reactants.

Question 29

Catalyst

Answer 29

catalyst
substance that decreases activation energy and increases reaction rate in a chemical reaction

Question 30

how does a catalyst increase the rate of a chemical reaction?

Answer 30

by decreasing the activation energy

Question 31

Enzyme

Answer 31

enzyme
protein that catalyzes chemical reactions for organisms

Question 32

What does it mean when an enzyme denatures

Answer 32

Enzymes work best in a limited temperature range or PH range that is around the organism’s normal body temperature or PH. At only slightly higher temperatures or PHs, the hydrogen bonds in an enzyme may begin to break apart. The enzyme begins to unravel and unfold, or denature.

Question 33

Applying heat to an egg causes proteins in the egg to become denatured. How can you tell that the proteins in this egg have been denatured? Select all correct answers.

Answer 33

The color of the egg changes. and Texture of egg changes

Question 34

What does all matter have in common?

Answer 34

B. It is made up of atoms.

Question 35

Which statement best describes compounds?

Answer 35

B. Compounds are made up of atoms of one or more elements bonded together.

Question 36

Which of the following are examples of matter? Select all correct answers.

Answer 36

water, grass, air (not heat not sunshine)

Question 37

An animal’s stomach contains enzymes that break down food into smaller molecules that the animal’s cells can use. Enzymes perform this function by:

Answer 37

C. decreasing the activation energy.

Question 38

A chemical reaction proceeds until it reaches an equilibrium. Which statement is true when the reaction is at equilibrium?

Answer 38

D. Both products and reactants are present.