Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
AS Biology
Appendix - Background info
| Question | Answer | Answer2 |
|---|---|---|
| An atom consists of | of a nucleus->containing protons and neutrons->they are surrounded by a cloud of electrons. | (blank) |
| Proton | has a (+) charge, the No of protons (referred to as the atomic number) determines the nature of the atom. | (blank) |
| Neutrons | Neutrons have a similar mass to protons, but they do not have a charge. | (blank) |
| Atomic mass | of an atom us equal to the combined mass of the protons and neutrons.->Atoms that occur naturally on the Earth contain from 1-92 protons. | ie. Hydrogen atom has only one proton in its nucleus, oxygen has 8. Electrons have very little atomic mass. |
| Hydrogen atom | has only one proton in its nucleus | (blank) |
| Atomic charges | the positive charges in the nucleus of an atom are balanced by negatively charged electrons. | |
| Electrons | have very little mass (only about 1/1840 of the mass of a proton.Sometimes electrons may be lost by an atom->atomic charge is no longer balanced. | (blank) |
| Ion | an atom in which the number of electrons does not equal the number of protons. ->Ions have an overall charge:-if electrons are lost the ion will be positive charged, if electrons are gained, the ion will have negative charge. | i.e. if atom of potassium lost an electron it becomes a (+) charged potassium ion (written K+); a chlorine atom (Cl) that gains an elect.->chloride ion (Cl-) |
| Chemical Symbol K | Potassium | (blank) |
| What does the equation "K -> K+ + e-" stand for? | that is an atom of potassium becomes a potassium ion by losing an electron. | (blank) |
| What does the equation "Cl + e- -> Cl-" stand for? | that is, a chlorine atom becomes a chloride ion by gaining an electron. | (blank) |
| What are the Calcium and Magnesium ions? | they both form ions by losing 2 electrons, so Ca-ion and Mg-ion both have 2 (+) changes . | (blank) |
| Cation | used for an ion with a positive charge | (blank) |
| Anion | used for an ion with a negative charge. | (blank) |
| Atoms | there are 92 naturally occuring types of atomes->they are refered to as elements. | (blank) |
| Elements | they each have a characeristic No of protons in thier nucleus->which gives the element its atomic number | (blank) |
| Atomic Number | is the same as ther characeristc number of protons. | (blank) |
| Molecule | relatively few substances occur naturally in the form of a pure element->most atoms are combined to form a stable structure referred to as a molecule. | Molecules often consist of more than 2 atoms. One reason why larger molecules form is that an atom may be able to share electrons with more than 1 atom. |
| Atoms join together to form molecules by: | 1. gaining one of more electrons, 2. losing one or more electrons, 3. sharing electrons with another atom. | (blank) |
| Positive Ion | when an atom loses an electron it becomes a positive ion | (blank) |
| Negative Ion | when an atom gains an electron it becomes an negative ion. | (blank) |
| Electher in their rovalent bond | => ionic bond. ->Opposite charges, that is, negative and positive, attract each other so that a positively charged ion and a negative charged ion will be held together by the attratction of opposite charges, forming an electrovalent bond. | (blank) |
| Covalent bond | result then 2 atoms share one or more pairs of electrons, thus forming a covalent bond. | ->when 2 atoms share 1 or more pairs of electrons.->a covalent bond is formed when 1 atom shares 1 or more pairs of electrons with another atom.->covalent bonds are stronger than electrovalent bonds! |
| Chemical bond | is a force which holds 2 atoms together. -> reults from the attraction of opposite charges->referred to as an electrovalent bond, or from sharing of 1 or more pairs of electrons->as in a covalent bond. | (blank) |
| Sodium chlorine | ->common table salt (NaCl) consists of reluar arrangements of sodium ions (Na+) and chloride ions (Cl-) held together by electrovalent bonds | the (+) and (-) charges of the ions attract each other & the sodium and chloride ion cluster together to form a crystal of salt, which is typically cube-shaped. |
| Explain why salt dissovels in water | water molecules break up the forces holding the ions together in their crystal structure and the salt dissoves to form a solution containing an mixture of free sodium ions (Na+) and free chloride ions (Cl-). | (blank) |
| double bond | when 2 atoms are joined by sharing 2 pairs of electrons | i.e. molecules formed by 2 atoms joined together for example osygen gas (O2), which consists of 2 atoms of oxygen, joined by the sharing of 2 pairs of electrons. |
| Organic substances | they ALL contain carbon atoms (C) and hydrogen (H) atoms.-> Each carbon atom can form 4 covalent bonds. | ie. when caron forms 4 single covalent bonds with 4 atoms of hydrogen (H) to produce molecule of methan (CH4). |
| Which are the 4 most common atoms which are found the most often in the 11 atoms are commonly found in living organisms? | 1. carbon (C), 2. oxygen (O), 3. hydrogen (H), 4. nitrogen (N), | (blank) |
| How many covalent bond do oxygen and nitrogen form? | Oxygen form 2 covalent bonds and nitrogen 3. | (blank) |
| What is the molecular formula of glucose? | C6H12O6 | (blank) |
| What does water consists of? | of an atom of oxygen covalently bonded to 2 hydrogen atoms. | ->the oxygen atom is surrounded by a stable arrangement of 8 (-) charged electrons |
| Polar | a water molecule is described as being polar bcs the charges ens. | (blank) |
| hydrogen bonds | the weak forces of attraction between partially positive (+) charges and partially negative (-) charges are referred to as hydrogen bonds. | many of the important properties of water result form the molecule having electon-rich/poor regions->giving part. (+)/(-)poles. ->weak forces of attraction between part. (+)/(-)charges. |
| What are the different properties of water? | 1. it is cohesive (adhesive), 2. water stores heat, (it has a high spedific heat), 3. large input of heat is needed to convert w. into vapour, 4. it acts as a solvent, 5. Water ionises | (blank) |
| Cohesion | Water molecules tend to cling to each other and to other polar molecules. Attraction between water molecules is referred to as cohesion. | (blank) |
| Adhesion | Water molecules tend to cling to each other and to other polar molecules. Attraction between water molecules and OTHER polar molecules is referred to as adhesion. | (blank) |
| latent heat of vaporisation | large input of heat is needed to convert w. into vapour | evaporation of water has a significant cooling effect. ->this is why evaporation of sweat is an important mechanism in the regulation of body temperature. |
| hydration shell | is the process that each ion becomes surrounded by a cloud of water moleculesell | Water molecules form a hydration shell around any molecule which has an electrical charge (ie. ion, partial/full elec. charge)->hydration shells form around ALL POLAR molecules when they dissolve in water. ->they are soluble in water. |
| Why does glucose dissolve in water? | bcs. water molecules form hydrogen bonds with the polar hydroxyl group, resulting in the glucose molecules being surrounded by a hydration shell. | (PS: Nonpolar molecules, such as fats, adn oils are NOT soluble in water) |
| Solubility | is defined as the maximum concentration that can be obtained of a substance when it is dissolved in a solvent. | hydration shells are soluble in water because the form around ALL POLAR molecules. |
| Ionisation | is the process when covalent bonds (between oxygen and hydrogen in water molecules) sometimes break, resulting in the formation of a proton (H1) and a hydroxide ion (OH-). | this process is represented by following chemical equation: H2O -> H(+) + OH(-) |
| solvent | is a liquid, such as water, in which other substances can disolve. | For example glucose (->solute) dissolves in water (->solvent) to form a solution. |
| solute | the substance which dissolves in the solvent is referred to as the solute. | For example glucose (->solute) dissolves in water (->solvent) to form a solution. |
| What are the "rules" of how to write chemical equations? | 1. we write the reactants on the left of the equation, 2. and the products on the right. 3. No of atoms need to be the same on both sides, | (blank) |
| Oxydation | is the LOSS of an electron/hydrogen by an atom, ion or molecule and is often accompanied by the loss of a hydrogen (H+) ion | (blank) |
| Reduction | is the GAIN of an electron/hydrogen -> the electron lost by one molecule is transferred to another. This process is called reduction. i.e. respiration involves individuall reactions | in which the substrate is oxidised by the transfer of hydrogen from the substrate to a hydrogen carrier. In this way the substrais oxidised and the hydrogen carrier is simultaneously reduced when it accepts the hydrogen. |
| Condensation Reaction | when 2 substances are combined by the removal of water. ->covalent bind is formed->reactions occur when for ex. 2 monosaccharid join to form a disaccharid->i.e. glucose+fructose join together by means of cond. reactions to formi sucrose. | reactions are important bcs. simple molecules can be joined in this way->forming large molecules->i.e. polysaccharide such as starch. |
| The Principle the chemical formula of condensation reaction | "A"-OH + "B"-H -> "A-B" + H2O | notice that OH is removed from A and H from B; H and HO join together to form water H2O. -> Substances A and B are now joined together hy means of covalent b |
| Peptide Bond | a covalent bond between the amino acids is known as a peptide bond. | if process is repeated ->progressively adding further amino acids -> to build up polypetide->each time a peptide bond is formed a molecule of water is released. |
| Glucose | Organic compound, a simple sugar (monosaccharide), chemical formula C6H12O6. | (blank) |
Created by:
1sabelle
Popular Biology sets