What is the mass number of an element?
Number of protons
Number of protons and neutrons
Number of protons, neutrons and electrons
True or false? Isotopes of the same element have the same physical properties but different chemical properties.
Which isotope of hydrogen has 1 neutron?
Protium
Deuterium
Tritium
What is the relative formula mass of a compound?
The sum of the atomic masses of each element relative to C-12
The mass of the compound which it has decayed from
The mass of the compound in micrograms
True or false? A mole of a substance is the amount that contains Avogadro's constant number of particles - this can be simplified to the relative formula mass in grams.
What percentage of magnesium oxide is magnesium? (RAM of Mg = 24, RAM of O = 16, magnesium oxide = MgO)
50%
55%
60%
65%
True or false? The empirical formula of a substance is the simplest ratio of the elements within it.
What is the empirical formula of the hydrocarbon containing 75% carbon? (RAM of C = 12, RAM of H = 1)
C2H3
CH2
CH3
CH4
What can we learn from the balanced symbol equation?
Number of molecules involved in each side of the reaction
Number of moles involved in each side of the reaction
The rate of the reaction
How much energy is required to carry out the reaction
Given that H2 + Cl2 --> 2HCl, what mass of HCl would you expect to produce with 17.75g of Cl2? (RAM of H = 1, RAM of Cl = 35.5)
17.75g
36.5g
73g
True or false? The formula to work out percentage yield is theoretical yield/actual yield * 100.
Given that CaCO3 --> CaO + CO2, what is the percentage yield of CaO if 100g of CaCO3 were used and 39g of CaO were collected? (RAM of Ca = 40, RAM of C = 12, RAM of O = 16)
70%
80%
Why is the percentage yield of a reaction rarely 100%?
The reaction may be reversible
Some of the product may not be collected
The reaction may be incomplete
The product may have been hidden
What is a reversible reaction?
One in which the reaction is always incomplete
One in which the products may react to produce reactants
One in which the products disintegrate upon production
Assuming that the reaction is reversible, what is the scientific notation for the reaction between ammonia and hydrogen chloride to form ammonium chloride?
NH3 + HCl --> NH4Cl
NH3 + HCl <--> NH4Cl
NH3 + HCl --> NH4Cl --> NH3 + HCl
True or false? One key application of chemical analysis is detection of illegal food additives such as tartrazine.
Which of these analytical methods does not rely on machinery?
Mass spectrometry
Gas chromatography
Paper chromatography
Which of these are advantages of using instrumental methods of analysis?
More expensive
Very accurate and sensitive
Quicker
Requires training to use
Can be used with small samples
Is only useful with known data to compare it to
What is measured to identify compounds in GC-MS?
Molecular ion peak
Retention time
What separates out compounds in a mixture in GC-MS?
