Answer:
b) 2.0 mol
Explanation:
Given data:
Number of moles of Ca needed = ?
Number of moles of water present = 4.0 mol
Solution:
Chemical equation:
Ca + 2H₂O → Ca(OH)₂ + H₂
now we will compare the moles of Ca and H₂O .
H₂O : Ca
2 : 1
4.0 : 1/2×4.0 = 2.0 mol
Thus, 2 moles of Ca are needed.
The answer is C
wood isn't a conductor but metal is
Answer: The correct option is B. A farmer with a field of solar panels
Explanation: Since the question says that the students are related to environmental group so they must run a campaign for the renewable energy resources and avoid the use of natural non renewable resources. coal, gas and many others like these are non renewable sources of energy. A farmer using solar panels in his field must be appreciated because he is using an environment friendly source of energy.
Answer:
i think the answer is C , atom mass increases with temperature
Answer:
A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas is a chemical change.
Explanation:
Hello.
In this case, since physical changes do not modify the molecular composition and structure of the material undergoing it whereas the chemical change does, for catalytic converters we should know they promote chemical reaction in which the composition is changed; for instance, for the given example, the following chemical reaction is the evidence:
As you can see, nitrogen and oxygen are no longer bonded but separated by themselves, therefore, this is a chemical change.
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