Answer:
Q = 246 kJ
Explanation:
It is given that,
Mass of water, m = 200 g
Let initial temperature, 
Final temperature of water, 
We know that the specific heat capacity of water, 
So, the heat energy needed to raise the temperature is given by :
or
Q = 246 kJ
So, the heat energy of 246 kJ is needed.
Answer: 61%
The reaction equation should be
CaF2 + H2SO4 → 2HF + CaSO4
For every 1 molecule CaF2 used, there will be 2 molecules of HF formed. The molecular mass of CaF2 is 78/mol while the molecular mass of HF is 20g/mol. If the yield is 100%, the amount of HF formed by 112g CaF2 would be: 112g/(78g/mol) * 2 * (20g/mol)=57.43g
The percentage yield of the reaction would be: 35g/57.43g= 60.94%
Answer 1. Since all the volcanic ash blocks out the sun's rays and is composed of many toxic chemicals including heavy amounts of anti-oxygen chemicals it will make the atmosphere around the volcano full of chemicals that make it hard for life to exist.
Answer 2. Photosynthesis is the process of converting water, Co^2, and sunlight into glucose and oxygen. Sunlight will be blocked out making it difficult for the plants to photosynthesize. Nearby waters will be contaminated too because of all the ash. The amount of C0^2 will be too overwhelming for most plants thereby killing many of them.
Answer 3. People can bring plants indoors and see that the plants are treated with care and properly. An alternative is to grow newer plants or gardens locally if possible. This will be ill-advised if you see lava coming straight towards your town.
Answer 4. Other events that can block out the sun are storms. If powerful enough they can block out the sun. Since the sun is our prime source of energy, we would seriously take a major hit population wise. Some plants might live if we use flashlights or other light alternatives. Animal's will die off and people eventually. Ends pretty bad and more complex.
what is the question ? I don't see any question but a few words
Metals are elements that are generally shiny when smooth and clean
