Key definitions in GCSE Chemistry

Pregunta	Respuesta
What is an atom	An atom is the smallest piece of an element that can exist.
What is the Atomic Number?	The number of protons in the nucleus of an atom is called the atomic number.
What is the Mass Number?	The number of protons plus the number of neutrons is called the mass number.
What is an Isotope?	Atoms of the same element may have different numbers of neutrons. These are called isotopes.
What is Relative Atomic Mass?	The mass number of any one atom will be a whole number. The relative atomic mass is the average mass number for all of the isotopes of that element.
What is the Difference between an Atom and an Ion?	If an atom loses or gains electrons it is no longer called an atom. It is called an ion. An ion has a full outer shell of electrons. An ion is either positive or negative because it has an electric charge.
Show reaction between chlorine and sodium using electron diagrams	When an atom of chlorine reacts it will gain one electron from sodium. The outer shell of chlorine will then have 8 electrons and be full. The chloride ion will have an extra electron and therefore an extra negative charge (shown as a - sign). Image: Formation-Sodium-Chloride.gif (image/gif)
What is Covalent Bonding?	When non-metals react with non-metals they share electrons and form a covalent bond. Covalent means sharing.
What is a Molecule?	A molecule is substance containing two or atoms joined by covalent bonds
What is the reactivity series	Image: reactivity_series.JPG (image/JPG)
Write the word equation for the reaction between sodium and hydrochloric acid	sodium + hydrochloric acid ==> sodium chloride + hydrogen.
What is a displacement reaction?	Displacement reaction occurs when a metal takes the place of a less reactive metal in a metal salt solution Fe(s) + CuSO4(aq) ==> FeSO4(aq) + Cu(s)
what is an Anion?	Anion is a negatively charged ion
What is Oxidation?	Oxidation is a process whereby an atom or ion loses one or more electrons..
what is Reduction	Reduction is a process whereby an atom or ion gains an electron
O. I. L. R. I. G. stands for	Oxidation Is Loss, Reduction Is Gain - of electrons.
What is an acid?	Any substance that produces Hydrogen ions (protons). Acids have a pH less than 7
In this equation which is the acid? HCl + H20 ==> H30+ + Cl-	HCl and H3O+
What is the difference between a STRONG acid and WEAK acid.	A Strong acid is completely ionised and all the acid is in the form H+
What is a Mole?	Number of Carbon(12) atoms in 12g of C(12) Value is 6x10(exp23)
How many moles sodium in 5g of sodium chloride?	Relative formula mass NaCl is 58g therefore moles=5/58 Answer 0.086
What mass of NaO will be formed by burning 20g in air?	moles Na =20/23 4Na + O(2)=2Na(2)O therefore 1 mole sodium oxide is formed for 2 moles Na = 10/23 moles RFM Na(2)O = 62 mass Na(2)O formed = 62*10/23 Answer 26.97g
What is empirical formula	Simplest proportion of elements in a compound Molecular compounds it may not necessarily be the same as the the RMM
What is Avogadro's Law	Avogadro's Law says that the same volume of gas contains the same number of particles. It does not matter what gas you have, they all contain the same number of particles provided that they are at the same temperature and pressure.
Definition of concentration of a Solution	Concentrations can be expressed as the number of moles in a particular volume or the number of grams in a particular volume.
Formula for converting moles to mass	moles = mass ÷ RFM mass = moles x RFM RFM = moles x mass

Siguiente

Key definitions in GCSE Chemistry

Descripción

Resumen del Recurso

Similar

	Creado por Ronak Thakrar hace alrededor de 10 años