Study guides, Class notes & Summaries

Accurate - Answer A measurement is considered accurate if it is judged to be close to the true value. Acid - Answer A sour substance which can attack metal, clothing or skin. The chemical opposite of an alkali. When dissolved in water, its solution has a pH number less than 7. Acids are proton (H+ ion) donors. Activation Energy - Answer The minimum amount of energy needed to start a reaction. Alkali - Answer A soluble base with a pH greater than 7. Makes OH- ions in water. Al...

What is the centre of an atom called? - Answer Nucleus What are the charges on protons, electrons and neutrons - Answer Protons= +1 Electrons= -1 Neutrons= 0 What are the relative masses of protons, electrons and neutrons - Answer Protons= 1 Electrons= 0.0005 Neutrons= 1 Why are atoms neutral? - Answer Because when the protons, electrons and neutrons charge they equal 0 overall -1+1+0= 0 so the atom is neutral What is an element - Answer A substance containing only one ...

Avogadro's constant - Answer the number of atoms, molecules, or ions in a mole of any substance (i.e., 6.02 × 10-23 per mol) concentration - Answer the amount of a substance dissolved in a given volume of liquid limiting reactant - Answer the reactant in a chemical reaction that when used up causes the reaction to stop mole - Answer the amount of substance in the relative atomic or formula mass of a substance in grams relative atomic mass Ar - Answer the average mass of t...

What is an atom? - Answer Smallest part of an element that can exist What is an element? - Answer A substance made up of one type of atom How are elements represented? - Answer Using symbols, in the periodic table Approximately how many elements are there? - Answer 100 What is a compound? - Answer A substance made up of two or more elements chemically combined in fixed proportions How are the elements in a compound separated? - Answer By chemical reaction How are ch...

Mean rate of reaction (with reactant) - Answer Rate of reaction: Quantity of reactant used ---------------------------- Time taken Mean rate of reaction (with product) - Answer Rate of reaction: Quantity of product formed ---------------------------- Time taken Measurements for quantity of product or reactant - Answer Either as mass in g or as volume in cm³ Measurements for the rate of reaction - Answer Either as g/s, cm³/s, or mol/s Factors which affect rate of c...

What is an *atom*? - Answer smallest part of an element What is an *element*? - Answer a substance that contains only one type of atom What are *chemical symbols*? - Answer - the letter or pair of letters that represents an element. - first letter is always capitalized What are *compounds*? - Answer substances in which atoms of two or more elements, which are chemically combined What is a *chemical formula*? - Answer a combination of symbols that shows the ratio of element...

How do you measure the rate of a reaction? - Answer By measuring the quantity of a reactant used or the quantity of product formed over time What is the equation for calculating the mean rate of a reaction by measuring the amount of reactant used? - Answer Mean rate of reaction = quantity of reactant used/time taken What is the equation for calculating the mean rate of a reaction by measuring the amount of product formed? - Answer Mean rate of reaction = quantity of product formed/ti...

Oxidation - Answer Loss of electrons Reduction - Answer Gain of electrons Displacement reaction - Answer When a more reactive element takes the place of a less reactive element in a compound Redox reaction - Answer A reaction where both oxidation and reduction occur Acid - Answer Substance that produces hydrogen ions (H⁺) in water Alkali - Answer Substance that produces hydroxide ions (OH⁻) in water Strong acid - Answer An acid which is fully ionised (split in...

What is the charge of a proton? - Answer +1 What is the charge of a neutron? - Answer 0 What is the charge of an electron? - Answer -1 What is the relative mass of a proton? - Answer 1 What is the relative mass of a neutron? - Answer 1 What is the relative mass of an electron? - Answer Very small How many types of atoms do elements contain? - Answer Only one type What are compounds? - Answer Substances containing two or more different elements that are chemic...

element - A pure substance made of only one kind of atom atom - the smallest component of an element having the chemical properties of the element periodic table - a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns. compound - A substance made up of atoms of two or more different elements joined by chemical bonds electron - A tiny, negatively...