<u>Answer:</u>
<em>1) ∆H is positive 
Endothermic
</em>
<em>2) 
Endothermic </em>
<em>3) Energy is absorbed Endothermic
</em>
<em>4) 
Exothermic
</em>
<em>5) ∆H is negtive Exothermic
</em>
<em></em>
<u>Explanation:</u>
∆H is called as enthalpy change
It is also called as Heat of reaction
Energy is required for the bond to break a bond.
Energy is released when a bond is formed.
that is
We see in this equation, bonds between hydrogen and chlorine molecules gets broken and on the right side bond is formed in HCl.
If energy of products greater than energy of reactants then the reaction enthalpy change is endothermic .
If energy of products lesser than energy of reactants then the reaction enthalpy change is exothermic .
For example
(positive hence endothermic)
(negative hence exothermic)
DDT was one of the first chemicals in widespread use as a pesticide.
<span><span>Food supplies: USDA found DDT breakdown products in 60% of heavy cream samples, 42% of kale greens, 28% of carrots and lower percentages of many other foods.</span><span>Body burden: DDT breakdown products were found in the blood of 99% of the people tested by CDC.</span><span>Health impacts: Girls exposed to DDT before puberty are 5 times more likely to develop breast cancer in middle age, according to the President’s Cancer Panel.</span></span>
Answer:
things that pollute the air
Explanation:
nuclear energy, fossil fuels, gas from cars and other transportation, and these all contribute to greenhouse gases that are harmful to the environment
hope this helped!
Answer:
29.41% of Calcium and 47.04% of Oxygen
Explanation:
The percent composition of an atom in a molecule is defined as 100 times the ratio between the mass of the atom and the mass of the molecule.
The mass of the molecule of the problem (Ore) is 46.28g. That means the percent composition of Calcium is:
13.61g / 46.28g * 100 = 29.41% of Calcium
And percent composition of Oxygen is:
21.77g / 46.28g * 100 = 47.04% of Oxygen
Answer:
d) Nucleus of the element does not change during the react
hope it helps (^^)
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