chapter 2 week 7/29 & 7-31

Question 1

What factors influences the rate of reactions?

Answer 1

Availability of the reactant - the more reactants available, the more chance they will come into contact with each other
The temperature of the environment influences the rate of the reaction.
When the temperature increases, the speed of molecular movement increases and the chance of molecules meeting improves.
Temperture also increases the velocity at which the reactants meet. The velocity provides the energy for the reaction.
Warm room -particles are moving faster
Velocity helps provide the energy for the reaction

Question 2

What is a chemical reaction?

Answer 2

the formation and breaking of chemical bonds

Question 3

What is a chemical equation?

Answer 3

the way in which the reaction is described in writing; it shows the molecular formula of the reactants (X and Y) and the products (Z) as well as the direction of the reaction (shown by the arrow)

X + Y —- Z

Question 4

What are the 3 types of chemical reactions?

Answer 4

synthesis, decomposition, and exchange reactions

Question 5

One type of chemical reaction is synthesis; explain?

Answer 5

synthesis reaction - when a new and more complex chemical is made from multiple, simpler chemicals.
X + Y —– XY Ex: O + O = O₂ (the formation of the oxygen molecule)
- occur in the body when the simple molecules absorbed during the digestive process are joined into larger molecules needed by cells for life processes
- new bonds are formed so energy is needed
- after bonds are formed, potential energy is stored in the chemical bonds

Question 6

Another type of chemical reaction is decomposition; explain?

Answer 6

when single, complex chemical is broken down into multiple, simpler chemicals
XY—–X + Y Ex: 2 H₂O—-2H₂ + O₂ (breakdown of water into hydrogen and oxygen gas)
- examples are the reactions that break down nutrients, such as fats in adipose tissue, into the simpler molecules (i.e., fatty acids) needed by the body.
- energy is released from the breaking of the chemical bonds ( the potential energy stored in the bonds is released)

Question 7

Last type of chemical reaction is exchange reaction; explain?

Answer 7

when certain atoms are exchanged between molecules. It is a combination of a synthesis and decomposition reaction
WX + YZ —- WY + XZ
example: the reaction of sodium bicarbonate given for indigestion relief, with hydrocholoric acid in the stomach
NaHCO₃ + HCL —– NaCl + H₂O + CO₂
(note: # of atoms of each element is the same on both sides of the chemical equation)

Question 8

What is the 2 in (2 H₂O)

Answer 8

the number 2 used as a prefix to a molecule denotes the number of molecules of reactant used or product created

Question 9

What do chemical reactions require?

Answer 9

input of energy or they release energy

Question 10

What is the activation energy?

Answer 10

the energy required for the reaction to happen

ex: kitchen match - use friction to light the match (the striking of the match is the energy to get it lit)

Question 11

What is a catalyst?

Answer 11

• what certain reactions require
• in living organisms they are usually special proteins that hold the reactants together so they may interact.
• they are not destroyed or used up by the reaction
• when more catalyst are present, the reaction speed is increased
  ex: yeast

Question 12

The digestion of food uses which type of chemical reaction?

Answer 12

decomposition reaction

Question 13

What is endothermic reaction?

Answer 13

when energy was put into the reaction - final product has more energy than the original reactant
ex: photosynthesis - (long term) seed to tree

Question 14

What is a exothermic reaction?

Answer 14

the end product has less energy than the original reactant. (cannot light a match once it has been used

Question 15

What are enzymes?

Answer 15

• special catalyst proteins
• lower the activation energy required for reaction & they speed up the rate of reaction
• fever kills off enzymes
• will denature the protein at a certain temperature and a certain ph

Question 16

What is a substrate?

Answer 16

substance acted on by an enzyme.

Question 17

What is enzyme substrate complex

Answer 17

combines with enzyme

Question 18

What are some factors that can influence the rate of reactions?

Answer 18

1. the availability of reactants - referred to as the concentration of reactants (the more reactants available, the more likely they will come in contact with each other)
2. the temperature of the environment - when temperature increases, the speed of molecular movement increases and the chance of molecules meeting improves. Temperature also increases the velocity at which reactants meet (the velocity provides the energy for the reaction)

Question 19

Molecules that make up living organisms are divided into two categories. What are they?

Answer 19

Organic and inorganic

Question 20

What are some facts about the term inorganic compounds?

Answer 20

• they do not contain hydrocarbon groups (hydrogen and carbon bonded together)
• they have ionic bonding
  Ex: water, salt, acids & bases - all important in living organisms

Question 21

What are some facts about organic compounds?

Answer 21

• are molecules that contain hydrocarbon groups & usually covalently bonded
• made up of carbohydrates, lipids, proteins, & nucleic acids
• made of hydrocarbon chains and often contain a functional group

Question 22

What is a functional group?

Answer 22

a group of atoms that defines the properties of the organic molecule.

Question 23

Are both organic and inorganic molecules essential for like on earth?

Answer 23

Yes