Chemical Reactions
Properties of Water
Chemical Reactions and Enzymes
Acids and Bases
Scientific Experiments and the Periodic Table
100
Describe what a compound is made of.
A compound is made up of atoms of one or more elements bonded together.
100
H30 reacts with OH to make what compound?
Water
100
In a chemical reaction, compounds and elements are combined to form products. Are the properties of the reactants the same as products?
No, the properties may differ.
100
Name and describe the scale that we measure Acids and Bases on
pH scale - a scale that measures a solutions acidity or alkalinity (base properties) by measuring its H+ concentration
100
Name 3 elements and their symbols from the Periodic table you know.
H – hydrogen O – Oxygen C – Carbon N – Nitrogen Na – Sodium Cl - chlorine
200
When two atoms _______ electrons this is a covalent bond.
Share
200
Name and explain the 3 main properties of water caused by hydrogen bonding
Adhesion – water bonding to other things (crawling up the sides of glass) Cohesion – Water bonding to itself (water beading up on top of aluminum foil) High specific heat – water resists changes in temperature (when a balloon is put over a flame it will light on fire, when a balloon with water in it will not because the water keeps the rubber cool enough because it resists the heat.
200
In a chemical equation, mass is not gained or lost. Explain what this means
It means that you will have the same number of each atom on both sides of the equations. For example, in the equation below there are 4H’s and 20’s on BOTH sides of the equation H30+OH = 2H20
200
What is the only substance that is neither basic or acidic
Pure water
200
Compare and contrast solids, liquids, and gases
Gas - A form of matter that has mass but no definite shape, and can be either compressed or expanded to fill an infinite volume. Liquid - A form of matter which has mass, occupies a volume, and flows to adopt the shape of its container. Solid - A form of matter which has a definite shape and volume.
300
Name the 3 sub atomic particles and their charges
Protons –positive Neutrons – No charge Electrons - negative
300
Explain the polar bond in water
Water has 2 “poles” – one that is slightly negatively (O) charged and one that is slightly positively (H) charged because the oxygen is greedy for the electrons they share
300
Describe the relationship between a catalyst and activation energy
When a catalyst is present, the activation energy is lower – meaning you need less energy to start a chemical reaction. )
300
Explain where acids and bases fall on the scale and what is in the middle (neutral)
Acids are from 0-6.9 Neutral is 7.0 Base are from 7.1-14 Neutral is pure water (h20)
300
Each Element on the Periodic table has a atomic number that matches the number of what sub atomic particle?
Protons
400
Compare Ionic Vs Covalent bonding
In covalent bonds they SHARE electrons, in ionic bonds they transfer electrons and create + and – ions.
400
Explain why water is called the ‘universal solvent’ and what kind of molecules dissolve in water
Water is the ‘universal solvent’ because many things dissolve in it but not everything. They types of molecules that dissolve in water are polar molecules because water is also polar.
400
Enzymes speed up the reaction of breaking apart a substrate (for example breaking down food in the stomach) create 2 examples of how you could positively or negatively affect the effectiveness of the enzyme
1) Add more enzymes to stomach but not more food (increase effectiveness) 2) Add more substrate (food) but not more enzyme (Decrease effectiveness) 3) Increase the temperature (decrease effectiveness because body works best at certain temperature)
400
Compare the difference in hydrogen concentration between acids and bases.
Acids have a higher hydrogen ion concentration. The lower the number on the pH scale below 7, the more the hydrogen ions. Bases are the opposite. They have lower hydrogen ion concentration. The higher the number on the pH scale above 7, the less hydrogen ions.
400
Explain 1-2 ways how you read the information on the periodic table
The large 1-2 letters in the center are the element symbol which is a short name for the full name (for example – H is the symbol for hydrogen). Atomic number – number of protons in a particular atom. Atoms in same period (row) have similar properties. Atoms in same group (column) react with other elements in the same way. Color coded by metals, nonmetals, and metalloids.
500
Justify why hydrogens bonds in water molecules are required for life. (Hint* start the sentence by saying ‘Without Hydrogen bonds______)
1.Without hydrogen bonds water wouldn’t have a high specific heat which means that it could not help you maintain homeostasis and regulate body temperature. 2.Hydrogen bonds cause water to have cohesion and adhesion, without these properties the top part of plants couldn’t get water because it needs this to have water travel from roots to top.
500
Water molecules have 3 types of bonds – name them
Covalent Bonds (sharing electrons) Polar Bonds, where they bond to other molecules that are of a different charge (- bonds with +) and Hydrogen bonds, which is a special kind of polar bond
500
Compare and contrast Exothermic and endothermic
Exothermic reactions need less energy to activate (get started) and usually give off light or heat. Endothermic reactions need a lot more energy to activate (get started) and absorb energy so are usually cold to the touch
500
A carnivorous plan consumes small bugs. It is usually found in areas with soil that is very alkaline (has base properties) without all the nutrients it needs. When it eats the bugs it gets the rest of the nutrient it needs. What type of soil is it found in and where does that fall on the pH scale.
Basic soil – which means the soil pH is above 7 to be basic and a lot above 7 to be very basic – probably between 13-14.
500
For the akla-seltzer lab, where we timed how long it would take for alka-seltzer to dissolve in cold, room temperature, and hot water. Name the Independent Variable, Dependent Variable, Control, constants
IV – the temperature (what I changed) DV – time (What I measured ) Control – room temperature water (that is the normal/neutral item). Constants – the amount of water, number of alka-seltzer tabs (things I made sure were the same to that the experiment was fair).
M
e
n
u