858376
Pregunta 1
Pregunta
What is the mass number of an element?
Respuesta
-
Number of protons
-
Number of protons and neutrons
-
Number of protons, neutrons and electrons
Pregunta 2
Pregunta
True or false? Isotopes of the same element have the same physical properties but different chemical properties.
Respuesta
- True
- False
Pregunta 3
Pregunta
Which isotope of hydrogen has 1 neutron?
Respuesta
-
Protium
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Deuterium
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Tritium
Pregunta 4
Pregunta
What is the relative formula mass of a compound?
Respuesta
-
The sum of the atomic masses of each element relative to C-12
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The mass of the compound which it has decayed from
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The mass of the compound in micrograms
Pregunta 5
Pregunta
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.
Respuesta
- True
- False
Pregunta 6
Pregunta
What percentage of magnesium oxide is magnesium? (RAM of Mg = 24, RAM of O = 16, magnesium oxide = MgO)
Respuesta
-
50%
-
55%
-
60%
-
65%
Pregunta 7
Pregunta
True or false? The empirical formula of a substance is the simplest ratio of the elements within it.
Respuesta
- True
- False
Pregunta 8
Pregunta
What is the empirical formula of the hydrocarbon containing 75% carbon? (RAM of C = 12, RAM of H = 1)
Respuesta
-
C2H3
-
CH2
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CH3
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CH4
Pregunta 9
Pregunta
What can we learn from the balanced symbol equation?
Respuesta
-
Number of molecules involved in each side of the reaction
-
Number of moles involved in each side of the reaction
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The rate of the reaction
-
How much energy is required to carry out the reaction
Pregunta 10
Pregunta
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)
Respuesta
-
17.75g
-
36.5g
-
73g
Pregunta 11
Pregunta
True or false? The formula to work out percentage yield is theoretical yield/actual yield * 100.
Respuesta
- True
- False
Pregunta 12
Pregunta
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)
Respuesta
-
50%
-
60%
-
70%
-
80%
Pregunta 13
Pregunta
Why is the percentage yield of a reaction rarely 100%?
Respuesta
-
The reaction may be reversible
-
Some of the product may not be collected
-
The reaction may be incomplete
-
The product may have been hidden
Pregunta 14
Pregunta
What is a reversible reaction?
Respuesta
-
One in which the reaction is always incomplete
-
One in which the products may react to produce reactants
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One in which the products disintegrate upon production
Pregunta 15
Pregunta
Assuming that the reaction is reversible, what is the scientific notation for the reaction between ammonia and hydrogen chloride to form ammonium chloride?
Respuesta
-
NH3 + HCl --> NH4Cl
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NH3 + HCl <--> NH4Cl
-
NH3 + HCl --> NH4Cl --> NH3 + HCl
Pregunta 16
Pregunta
True or false? One key application of chemical analysis is detection of illegal food additives such as tartrazine.
Respuesta
- True
- False
Pregunta 17
Pregunta
Which of these analytical methods does not rely on machinery?
Respuesta
-
Mass spectrometry
-
Gas chromatography
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Paper chromatography
Pregunta 18
Pregunta
Which of these are advantages of using instrumental methods of analysis?
Respuesta
-
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
Pregunta 19
Pregunta
What is measured to identify compounds in GC-MS?
Respuesta
-
Molecular ion peak
-
Retention time
Pregunta 20
Pregunta
What separates out compounds in a mixture in GC-MS?
Respuesta
-
Molecular ion peak
-
Retention time
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