Test 2 Flashcards
What is an element? Give two examples.
Pure substance made up of a type of atom. Hydrogen, Oxygen.
What is an atom made up of?
Three subatomic particles.
What are the subatomic particles that make up the atom?
The proton, neutron, and electron.
How is a proton charged? How is a neutron charged? What do they do?
A proton is positively charged. A neutron has no charge. They form the nucleus.
What is the nucleus of an atom?
The center.
How is an electron charged? How big is it? What does it do?
Negatively charged. 1/1840 the mass of a proton. They are in constant motion around the nucleus and balance out the positive charge from proton.
What is the atomic number and how is it chosen? Give an example.
It’s the number that identifies the element. It’s chosen by the number of protons. (Carbon, 6. Hydrogen, 1.)
List the building blocks that make up 99% of living things.
Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, Phosphorus, Sulfer
What is a molecule? Give an example.
Two or more atoms held together by chemical bonds. Water, H2O
What is a symbol? Give an example.
A symbol is a letter or couple letters that an element is known as, such as H, hydrogen, or O, oxygen.
Give an example of how joining elements into a compound can make it act differently.
Again, H2O. Hydrogen and Oxygen=Water…
What is an atom?
A basic unit of matter that cannot be divided.
What is a compound?
Made of of two or more elements.
What does a chemical bond do? Which type of electrons hold it together?
Holds atoms in compounds together. The valance electrons, the outer electrons in the atoms, form the bonds.
What is an ionic bond?
A bond when electrons are transferred from one atom to another.
What is an ion?
An atom with an ionic bond. It either has a positive or negative charge.
What is a covalent bond?
When electrons are shared between the two atoms.
Water is the most abundant compound in…
Most living things.
What is water’s overall charge? What does this mean?
Neutral. This means it has a equal number of protons and electrons.
In water, does the hydrogen atom have a stronger pull for the shared electrons? Or the oxygen? What does this mean about the oxygen and hydrogen?
The oxygen. Therefore, it has a slight negative charge and the hydrogens have a slight positive charge.
What is water made up of and what is its compound symbol?
Two hydrogens and an oxygen. h2o.
Why is water said to be polar?
Because the oxygen atom has a slight negative charge and the hydrogen atoms have a slight positive charge.
What are the hydrogen bonds?
The weak bonds between the hydrogen atom of one water molecule and oxygen atom of another.
Where are ionic bonds, covalent bonds, and hydrogen bonds? Which bond is weaker than the other two?
Ionic and covalent bonds are inside the molecules, between the atoms, and the hydrogen bonds are between molecules.Hydrogen bonds are weaker.
What is cohesion? What is it due to? What does it cause?
The attraction of water molecules to other molecules. This is due to the hydrogen bonds between water molecules. This causes water to form a bead when dropped on a surface because the water molecules are attracted in.
What is adhesion?
The attraction between molecules of one substance and the molecules of another.
Why does water adhere well to other substances? What does this cause?
It adheres well because it is polar. Water therefore sticks to the sides of thin tubes.
What is capillary action? How does this help plants?
In a very thin tube, water can rise because of adhesion and cohesion. This helps pull water up into stems and leaves of plants.
What is surface tension?
Because of cohesion (the strong attraction of water molecules to itself) substances can be supported on its surface.
Why is water resistant to temperature change?
Since water is cohesive, a lot of heat must be used to overcome the cohesion. Therefore, the water temperature changes very slowly.
What happens to the molecules when water freezes? What does this cause?
The molecules spread apart and have more air space. This causes ice to be less dense, so ice floats in water.
What is a solvent?
A solvent is a substance that dissolve other substances.
Why is water a good solvent?
Because the adhesion of water molecules to other molecules is strong enough to break them apart.
What is a mixture?
A material compose of two or more elements or compounds that are physically mixed together but not chemically combined.
What is a homogeneous mixture?
The substances in the mixture are distributed evenly/appears the same throughout . Ex:Air-n2o2co2
What is a solution?
A liquid homogeneous mixture.
What is a solute?
The substance dissolved in the solvent.
What is a heterogeneous mixture?
When the substances in a mixture are visibly different.
What is a suspension? Give an example.
A suspension is a heterogeneous mixture of water and undissolved material that is found in small pieces, such as sand and water, blood.
What is an ion?
A charged atom.
What does the pH scale tell us?
How acidic or basic a substance is.
If something is acidic, it has ____
More H+, hydrogen ions.
If something has equal H+, hydrogen, and OH-, hydroxide, ions, it is___
Neutral
If something has more OH- (hydroxide) ions, it is ___
Basic
What is acid?
A compound that produces H+ ions that will dissolve in water.
List the properties of acid and give an example.
-corrosive (will break things down)
-tastes sour
Hydrochloric acid, HCl
Why is HCl an acid?
HCl–> H+ and Cl-
H+ means acid
What is a base?
A compound that produces hydroxide ions that dissolve in water.
List the properties of base and give an example.
-feels slippery
-tastes bitter
Ex:NaOH, sodium hydroxide
Why is Sodium hydroxide a base?
NaOH—> Na+ and OH-
OH- means basic
What is the pH of pure water? Why?
7, because it has an equal amount of H+ and OH- ions.
What happens when acids and bases are mixed together?
Neutralization. It’s a reaction between the H+ and OH- ions. H+ and OH- is H2O, which makes it neutral.
What should the pH of human blood be?
Between 7 and 7.5
What is an indicator?
A substance that changes color when the pH goes above or below a certain level.
What are two pH indicators?
Litmus paper. It turns red in acidic pH and blue in basic pH.
Phenolphthalein-changes from colorless to pink in basic solutions.
What are organic compounds?
Compounds that contain bonds between carbon atoms.
Besides carbon, what do most organic compounds contain?
Hydrogen
Where do most organic compounds occur naturally?
Living organisms.
What do inorganic compounds NOT contain?
Carbon bonded to Carbon.
What is a valance electron?
Electron in the outer shell of an atom.
How many valance electrons does Carbon have?
4
How many valance electrons does Carbon need to be complete?
4.
How many bonds can Carbon form? Why?
4, because it has four valance electrons and needs an additional four to be complete.
Can Carbon form bonds with many different elements? List.
Yes. H, O, nitrogen, phosphorus, sulfur, other Carbon.
What are the shapes Carbon can be found in?
Chains or rings.
What is a double bond?
When the carbon shares two pairs of electrons instead of one.
What does Carbon containing compounds often form? What are their abilities?
Units. They can exist on their own or can bond together, one after another.
What is a monomer?
A single unit.
What are polymers?
Large molecules of repeating units.
What do monomers join to form?
Polymers.
How are polymers formed?
Polymerization.
What is polymerization?
The process by which smaller molecules join together to form larger ones.
What is dehydration synthesis?
Joining monomers together by removing water.
In dehydration synthesis, how are water molecules removed?
One water molecule is removed for each monomer that is added to the chain.
How do the monomers donate the water molecules in dehydration synthesis?
One monomer donates the hydrogens, the other monomer donates the oxygen.
How do monomers bond each other?
Covalent ly.
Where does the bond between monomers form?
Where the OH was removed and bonded to the remaining oxygen.
What does the process of dehydration synthesis do?
Requires energy.
How does a polymer break into monomers?
Hydrolysis.
What is hydrolysis the reverse of?
Dehydration synthesis.
What is hydrolysis?
Breaking a bond between two monomers by adding water.
In hydrolysis, how are water molecules added?
One water molecule is added for each monomer that is removed from the chain.
How do the monomers get the water molecules in hydrolysis?
Hydrogen from the water attaches to one monomer, and the oxygen and the other hydrogen from the water attach to the other monomer.
What does the process of hydrolysis do?
Releases energy.
When does hydrolysis happen?
During food digestion.
What are the top four building blocks?
Oxygen, Hydrogen, Carbon, Nitrogen.
