C2.3 Flashcards
What is the atomic number of an atom?
Number of protons.
What is the mass number of an atom?
Number of protons and neutrons.
How does the mass of an electron compare with the mass of a neutron or proton?
Electrons are much lighter.
What are isotopes?
Atoms of the same element with different numbers of neutrons.
Why don’t symbol equations tell us exactly what mass of each reactant to use in a chemical reaction?
Because atoms of different elements have different masses.
Which atom do we use as a standard to compare relative masses of elements?
Carbon-12
What is a mole?
Relative atomic mass in grass or relative formula mass in grams.
2HCl has two meanings. What are they?
Balanced and unbalanced.
What is the percentage yield of a reaction?
=amount of product produced/max amount of product possible
x100%
What are chemical factories designed by?
Chemical engineers.
What does a single arrow in a chemical equation mean?
Reversible reaction.
What does a double arrow in a chemical equation mean?
Reversible reaction can go in both directions.
Why does a neutral solution look purple with litmus solution?
Because it is a complex molecule which reacts with an alkali to form a different colour.
What is a food additive?
A substance that’s added to food to extend its shelf life or to improve its taste or appearance.
What is a technique used to identify food additives?
Paper chromatography.
