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| Question | Answer |
| Chemistry | Chemistry |
| what happens when you add water (with colourless particles) to copper sulphate solution (with coloured blue particles)? | the copper sulphate solution is diluted and the particles become more spread out and less of the copper sulphate particles so the solution becomes a lighter blue as you add more water into the container |
| what happens when you add potassium manganite to water (colourless particles)? | the particles of the potassium magnate spread out into the water. this is called diffusion |
| finish this sentence atoms are particles... | that cannot be broken down any further |
| finish this sentence elements consist of... | only one type of atom |
| finish this sentence a molecule consists of ... | two or more atoms chemically bonded together |
| finish this sentence a compound consists of... | atoms of two or more elements chemically bonded together |
| finish this sentence a mixture is ... | 2 or more elements/compounds not chemically bonded together |
| describe the experiment for chromatography | 1. draw a line in pencil on a piece of filter paper then draw 4 or more dots on with a pen. 2. place the piece of paper in water making sure the water doesn't pass the pencil line. 3. the colours will slowly separate out |
| atoms consist of a central... | nucleus |
| the nucleus contains particles called...and... | protons and neutrons |
| other particles called...orbit the nucleus in shells | electrons |
| what is the relative mass and the charge of a proton | relative mass = 1 charge = +1 |
| what is the relative mass and the charge of a neutron | relative mass = 1 charge = 0 |
| what is the relative mass and charge of a electron | relative mass = 1/2000 charge = -1 |
| atoms have no overall... | charge |
| what is the mass number? | number of protons and neutrons. it is the small top number on the left of the symbol |
| what is the atomic number? | the number of protons, it is the small bottom number on the left of the symbol |
| what are the number of electrons the same as? | the number of protons |
| how many protons, neutrons and electrons does the element sodium have with the mass number 23 and the atomic number 11? | protons =11 neutrons = 12 electrons = 11 |
| how many protons, neutrons and electrons does calcium have with the mass number 40 and the atomic number 20? | protons = 20 neutrons = 20 electrons = 20 |
| elements in the periodic table are... | placed in order of atomic number. |
| electron configuration what is the maximum number of electrons in: shell 1 shell 2 shell 3 | shell 1 = 2 shell 2 = 8 shell 3 = 8 |
| isotopes are ... | atoms of the same element which have the same number of protons but different numbers of neutrons e.g. hydrogen has 3 isotopes |
| relative atomic mass (Ar) is... | the mass of atoms of an element measured relative to C |
| how do you calculate relative atomic mass using bromine as an example? | bromine has 2 isotopes, 50% are Br with a mass number of 79 and a atomic number of 35 and 50% are Br with a mass number of 81 and a atomic number of 35. ArBr = (50x79) + (50x81) =80 100 |
| what is the relative formula mass (Mr) of a substance? | the relative formula mass of a substance is the sum of the relative atomic masses of all the atoms present |
| Hydrogen H2 Ar H =1 H:2 (atoms) x 1 (Ar) = 2 | water = H2O Ar H = 1 Ar O = 16 O = 1x16 = 16 H = 2x1 = 2 Mr H: 2 O: 16 = 18 |
| sodium hydroxide NaOH Ar Na = 23 Ar O = 16 Ar H = 1 1x23=23 1x16=16 1x1 = 1 23+16+1 = 40 | iron oxide Fe2 O3 Ar Fe = 56 Ar O =16 Fe = 2 x 56 =112 O = 3x16 =48 112 + 48 = 160 |
| iron hydroxide (rust) Fe(OH)3 ArFe=56 ArO=16 ArH=1 1x56=56 3x16=48 3x1=3 =107 | Ethanol C2 H5 OH ArC=12 ArO=16 ArH=1 2x12=24 6x1=6 16x1=16 =46 |
| ammonium sulphate (NH4)2 SO4 ArN=14 ArH=1 ArS=32 ArO=16 2x14=28 8x1=8 1x32=32 4x16=64 =132 | . |
| ionic bonding takes place between... | a metal and a non-metal |
| the metal atom... | loses electrons and becomes an ion with a positive charge |
| the non - metal atom... | gains electrons and becomes and ion with a negative charge |
| electrons are... | transferred from one atom to another. |
| the ions are... | held together by strong electrostatic attraction between oppositely charged ions |
| ... compounds are made from metals and non-metals | ionic |
| metals always form...charged ions and non metals form...negative charged ions. | positive negative |
| these ions are arranged in ... ionic structures. | giant |
| their crystals have ... melting points and many will ... in water | high dissolve |
| they conduct ... when molten or when in solution, but not when they are ... | electricity solid |
| which of these substances have ionic bonds? 1) ammonia NH3 2) water H2O 3) copper oxide CuO 4) zinc chloride ZnCl2 5) lead bromine PbBr2 6) potassium fluorine, KF 7) methane CH4 | 3, 4, 5, 6 |
| how did you know they had ionic bonds? | these all have ionic bonds because they have to have 1 metal and 1 non-metal to have an ionic bond |
| ionic compounds have... | high melting and boiling points because of the strong attraction between the ions (solids at room temperature) |
| the greater the charge on the ions ... | the higher the melting point. |
| Which of these has a high and a low melting point and why? NaCl MgO Na+Cl- Mg2+O2- | NaCl has a low melting point as it has a lower charge on the ions. MgO has a high melting point as it has a greater charge on the ions. |
| ionic crystals are ... | giant lattices held together by attractions between the ions. e.g. sodium chloride (NaCl) |
| ionic compounds are mostly soluble in... | water |
| ionic compounds can conduct electricity when... | dissolved in water or molten because the ions can move |
| how does the structure of a sodium ion differ from the structure of a sodium atom? | because a sodium ion has 2 positive charges and ten electrons however a sodium atom has twelve electrons. |
| how does the structure of a chloride atom differ from the structure of a chloride atom | |
| what is the type of chemical bond present in sodium chloride? | ionic bonding |
| how can sodium chloride crystals be cube shaped? | because the ions are arranged in a lattice format. |
| solid sodium chloride has a high melting point because ... | the ions have a greater charge. |
| sodium chloride is an electrical insulator... | because it has a high attraction between the ions which have a high charge. |
| molten sodium chloride will undergo electrolysis because... | they are held together. |
| Simple Molecular bonding simple molecules only contain: a) a few atoms b) a lot of atoms c) four or five atoms | a) A few atoms |
| the bonding in the molecule is strong but the forces between the molecules are ... | weak |
| very little energy is needed to separate the molecules so most simple molecules are ... | liquids or gases at room temperature |
| Giant Covalent Structures | these have very large numbers of atoms with a large number of covalent bonds. |
| a large amount of energy is needed to break the ... | covalent bonds so giant structures have very high melting points and boiling points and are solids. |
| Graphite each carbon atom bonded to ... | 3 others |
| graphite forms in layers which can | slide over each other |
| "free" or ... electrons can conduct electricity. | delocalised |
| Graphite is used in ... | lubricants |
| what does the giant covalent structure of graphite look like? | |
| Diamond is used in ... | cutting tools |
| Diamond Each carbon atom bonded to ... | 4 others |
| diamond is very ... | hard |
| what does the giant covalent structure of diamond look like? | strong covalent bonds between all the carbon atoms |
| In metals the outer shell electrons are... | delocalised ( free to move) |
| metallic structures consist of ... surrounded by a sea of delocalised electrons. | positive ions |
| the metal structure is held together by ... | a stronger attraction between the positive ions and delocalised electrons |
| metals are ... due to these ... the atoms can slide over each other without the metal breaking | malleable ( can be bent/shaped) strong forces |
| metals can conduct electricity as the delocalised electrons can ... | carry charge |
| why is the formula for the compound formed when sodium and chlorine react NaCl and not NaCl2? | because there is only one atom of chlorine when combined |
| what happens when magnesium reacts with chlorine to form magnesium chloride ( MgCl2 ) | 2 of the magnesium's electrons are transferred to 2 Chlorine atoms |
| what has the substance been made from? | a metal (magnesium) and a non metal (chlorine ) |
| why does Chlorine oxide have a low melting point? | the covalent bonds are not strong |
| why is graphite soft? | because weaker forces hold the layers together |
| why can Graphite conduct electricity? | because it has 'free' or delocalised atoms |
| what is a Covalent bond? | a strong attraction between the shared electrons and the nuclei of the atoms |
| a dot and cross diagram only shows ... | the outer electron shell |
| covalent bonding only happens between ... | non metals |
| the outer electrons are... | shared |
| atoms have ... | full outer shells after sharing |
| ionic Bonding metal ... electrons non- metal ... electrons | looses gains |
| transferred positive ion strong attraction negative ion = high melting points | . |
| why can metals conduct electricity? | the delocalised electrons can carry charge. this conductivity increases across the periodic table because there are more delocalised electrons |
| during the formation of a covalent bond the atoms ... | share electrons |
| why does sodium chloride have a relatively high melting point? | as it has strong covalent bonds that must be broken. this takes a lot of energy which can be found at high temperatures. ( it is a giant covalent structure) |
| which of these has a molecular structure and which of these has a ionic structure. 1) sulphur dioxide 2) nitrogen dioxide 3) calcium fluoride 4) carbon dioxide 5) potassium chloride 6) sodium oxide | molecular - 1,4,2 ionic - 5, 6, 3 |
| why can metals be pulled into wires? | because the electrons can move around and the atoms can slide over each other without the metal breaking |
| Why can magnesium chloride only conduct electricity when it is melted? | as it is an ionic compound |
| why is magnesium oxide used to line furnaces? | because it has a high melting point |
| why does silicon have a high melting point? | it has a giant lattice structure and it has a high melting point because it has strong covalent bonds which takes a lot of energy to break. this energy is only found at high temperatures. |
| why can diamond not conduct electricity? | there are no free ions or electrons to carry the charge |
| explain how the atoms are held together in a molecule of hydrogen chloride | because the atoms have a strong attraction between the shared electrons and the nuclei of the atoms. |
| explain in terms of its bonding and structure why silicon carbide has a high melting point. | SiC will have a high melting and boiling point as strong covalent bonds must be broken and this takes a lot of energy which is only available at high temperatures |
| why does the structure of graphite make it a useful lubricant? | each carbon atom is only covalently bonded to three other carbon atoms. Graphite contains layers of carbon atoms. the layers slide over each other easily because there are only weak forces between them, making graphite lubricant |
| explain why diamonds structure makes it a useful cutting tool | diamond is extremely hard and has a high melting point because of its lattice structure. |
| why can Graphite conduct electricity? | the electrons are only held loosely to the carbon atoms. they can drift along the layers in Graphite. these delocalised electrons make graphite a good conductor of electricity |
| Electrolysis an electric current is a flow of ... | electrons or ions |
| ionic compounds can conduct electricity when molten or dissolved in ... | water i.e. when the ions are free to move |
| electrolytes are ... | liquids which conduct electricity |
| electrolysis is the ... | breakdown of a substance using electricity |
| the positive electrode is called the ... | anode |
| the negative electrode is called the ... | Cathode |
| explain the electrolysis of molten lead bromide ( PbBr2) | electrolysis splits the lead bromide into lead ions and bromide ions (Br-) and (Pb2+). at the cathode the lead ions gain two electrons and become lead atoms (a grey solid forms) Pb2+ +2e- > Pb at the anode two bromide ions each loose an electron and a molecule of bromine form as a gas. 2Br- - 2e- > Br2 electrons move in the external circuit, ions move in the liquid |
| Gain of electrons is ... | reduction |
| Oxidation is | loss |
| lead bromine is an ionic substance which doesn't easily dissolve in water. how could it be made into a liquid for electrolysis? | make it molten |
| an aqueous solution of sodium chloride (NaCl) is being electrolysed. predict the products in the reaction and give their names. | negative electrode - sodium solid positive electrode - chlorine gas |
| explain why the product at the negative electrode is formed | sodium ions gain electrons |
| the periodic table the elements are arranged in ... | order of their atomic number |
| columns are ... rows are ... | groups periods |
| metals are found on the ... non metals on the ... | left right |
| all metals conduct ... | electricity |
| metal oxides are ... they ... acids | basic neutralise |
| non metal oxides are ... and react with ... | acidic bases |
| elements in the same group have the ... because they have the same ... | same chemical properties number of electrons in the outer shell (equal to the groups number) |
| what group is Li 2,1 Na 2,8,1 K 2,8,8,1 in. Why? | group 1 because they all have 1 electron in the outer shell |
| group 0 are called the | noble gases |
| these are very unreactive because their outer shells are | full |
| what is the name for group 1? | the alkali metals |
| they have a ... so they ... in water | low density float |
| they are ... so they can be ... with a knife. | soft cut |
| they are very ... so they react easily with ... and ... | reactive water oxygen |
| reaction with water produces an ... and hydrogen gas. e.g. lithium + water > lithium hydroxide + hydrogen 2Li + 2H2 O > 2LiOH + H2 | alkaline hydroxide solution |
| alkali metals ... as we go down group 1 | increase in reactivity |
| the electron in the outer shell is ... (2 reasons) | further away from the nucleus move shielded from the attraction of the nucleus |
| Do Group 1 metals have high melting points? | no |
| what are the alkali metals stored under? | oil because they react with oxygen and water |
| which substance is the least reactive member of the group? | Lithium |
| what do you use to find the PH of a solution? | universal indicator |
| how do you test for hydrogen | you place a tube over another boiling tube with the alkaline metal in, they you light a splint and place it under the tube and if it makes a pop then hydrogen is being formed. (the squeaky pop test) |
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