A: making s sandcastle. This is because water and sand is only a mixture, so they do not react with each other. All the rest include chemical reactions!
Answer;
-More carbon dioxide causes an increase in carbonic acid (H2CO3) which leads to a decrease in the concentration of carbonate ion (CO32-).
Explanation;
-Carbon dioxide is added to the atmosphere whenever people burn fossil fuels. Oceans play an important role in keeping the Earth's carbon cycle in balance.
-As the amount of carbon dioxide in the atmosphere increases, the oceans absorb a lot of it. In the ocean, carbon dioxide reacts with seawater to form carbonic acid which causes the acidity of seawater to increase.
-As long as we keep putting extra carbon dioxide in the atmosphere, the acidity of the ocean will continue to increase. The effect is that; Increasing acidity makes it harder for corals to build skeletons and for shellfish to build the shells they need for protection. Corals are particularly important because they provide homes for many other sea creatures.
Cu(NO3)2>NO2+CuO+O2 balanced: 2Cu(NO3)2=4NO2+2CuO+O2
This problem is providing the mass, energy, initial temperature and specific heat of a sample of copper that is required to calculate the final temperature.
Thus, we recall the general heat equation:
Which has to be solved for the final temperature, 
as follows:
Finally, we plug in the numbers to obtain:
However, this result is not given in the choices.
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