Section 1: Principles of Chemistry Flashcards
What is the definition of diffusion?
The net movement of particles from an area of higher concentration to an area of lower concentration
What increases the rate of diffusion?
Higher energy and lower mass of particles
Which two solutions are used in the experiment to test how density of particles affects rate of diffusion?
Hydrochloric acid (HCl) and ammonia solution (NH4)
Are ammonia particles heavier than hydrochloric acid particles?
no
What is the white substance formed when hydrochloric acid and ammonia react?
Ammonium chloride
In the experiment testing how the density of particles affects the rate of diffusion, does the white ring form closer to the hydrochloric acid or ammonia solution?
Hydrochloric acid
What is the experiment to show diffusion occurring in air?
Bromine in a gas jar
What is the definition of an atom?
the smallest particle of an element
What is the definition of a molecule?
Two or more non-metal atoms held together by covalent bonds
What is the definition of an element?
a pure substance made of only one kind of atom
what is the definition of a compound?
A substance containing two or more elements bonded together in a fixed ratio
what is the definition of a mixture?
a combination of two or more substances that are not chemically combined
what is filtering used to separate?
Insoluble particles from a liquid (e.g. sand from water)
What is evaporation used to separate?
Dissolved substances from a solution (e.g. salt from a salt solution)
What is simple distillation used to separate?
The liquid from a dissolved solid in a solution (e.g. water from a salt solution)
What is fractional distillation used to separate?
Liquids from a mix of liquids (e.g. alcohol from a mix of alcohol and water)
What is chromatography used to separate?
A mixture of soluble substances (e.g. the colours found in ink)
What is crystallisation used to separate?
Solids from a solution (when hot solution is left to stand, allowing crystals to form)
What do chromatographs show?
How many different substances in a substance and their relative solubility (the most soluble solvent will travel the furthest)
What is the relative charge of a proton?
+1
What is the relative mass of a proton?
1
what is the relative charge of an electron?
-1
what is the relative mass of an electron?
1/1840
what is the relative charge of a neutron?
0
what is the relative mass of a neutron?
1
what is found in an atoms central nucleus?
protons and neutrons
how many electrons are in the first shell?
2
how many electrons are in the second shell?
8
how many electrons are in the third shell?
8
where are electrons found in an atom?
orbiting the nucleus in shells
what is the definition of atomic number?
the number of protons in the nucleus of an atom
what is the definition of mass number?
the total number of protons and neutrons in the nucleus of an atom
what is the definition of an isotope?
atoms of the same element with a different number of neutrons
what is the definition of relative atomic mass (Ar)?
the average mass of the atoms of an element
How do you calculate the relative atomic mass?
∑(isotope mass x isotope abundance) ÷ 100
what is the periodic table?
an arrangement of elements in order of atomic number
What does a group in the periodic table tell you about the element?
The number of electrons in the element’s outer shell and the charge of the elements ion
What is the charge on an ion of an element in group 2?
+2
What is the charge on an ion of an element in group 7?
-1
What does a period in the periodic table tell you about the element?
The number of shells with electrons in and element has
what is formula mass?
the sum of the atomic masses of all the atoms in the compound
what are moles?
The Avogadro number of particles in a substance (represents the amount of substance)
what is the formula to calculate moles from mass and formula mass?
Moles = mass ÷ formula mass
What is the molar volume of gas?
24 dm3 or 24,000 cm3
what is the formula to calculate moles from volume?
Moles = volume ÷ 24dm3
What is the state symbol for solids?
(s)
what is the state symbol for liquids?
(l)