Criteria A
1-B
2-A
3-A
4 a) a substance that increases the rate of a chemical reaction without itself
undergoing any permanent chemical change.
b- Z , because producing the same amount of product requires more time in this
reaction
5- a)Butane
b) C,D,E
6. a- Ethane
b- organic chemical compounds composed only of the elements carbon (C) and
hydrogen (H).
Criteria B
7. a) As the reaction starts hydrogen gas produces, which enters from the conical
flask into the measuring cylinder. The volume of hydrogen gas(measuring cylinder)
should be recorded every 5 seconds (stopwatch). A table should be created in order
to add all results. Then numerical data needs to be changed into a smooth line
graph.
b) Increasing the concentration of sulfuric acid increases the rate of reaction, if the
concentration of reactants is increased, there are more reactant particles moving
together, which means more successful collisions.
c) The rate of reaction increases, because using a powder instead of a lump
means the increasing surface area, which means a greater area of reactant is
exposed and so available for a successful collision
d) An increase in temperature typically increases the rate of reaction, which means
more kinetic energy of the reactant molecules and more successful collision.
Criteria C
8. a) Table of results volumes correctly completed (4), -1 for each incorrect 0, 18,
34, 42, 59, 63, 63
b) smooth line graph
Criteria D
1. Glacial ice and the air bubbles trapped within it are an important tool in the
study of climate because they range in age from several hundred to several
hundreds of thousands of years. This means that they function as a long-term
climate record; through drilling and extracting ice cores scientists can
ascertain year-by-year information about past climate; the information
scientists can find include: “past atmospheric composition, temperature
variations, and types of vegetation”.
2. To help scientists in their future work, past eras can be reconstructed and
modelling done to explain previous climate change and predict future climate
patterns; global warming can be studied and explained by studying changes
in glaciers, as they are very sensitive to temperature fluctuations.
3. By discovering and analyzing this type of information, scientists assist
governments and bodies, such as the United Nations, in their planning of
policies, programs and legislation; to limit future climate change and its
negative effects on our planet and humankind.
4. During the 20th century and before, burning fossil fuels for manufacturing,
transportation and production of electricity has led to increased carbon dioxide
in the atmosphere. The concentration of other gases in the atmosphere, such
as methane, has also increased greatly. These greenhouse gases reflect heat
energy being radiated from the surface of the earth, resulting in an increase in
global temperatures. Other factors have also contributed to global warming
including dust and soot from grazing, farming and manufacturing.