<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)
Hello!
1.00 L of a gas at STP is compressed to 473 mL. What is the new pressure of gas?
- <u><em>We have the following data:</em></u>
Vo (initial volume) = 1.00 L
V (final volume) = 473 mL → 0.473 L
Po (initial pressure) = 1 atm (pressure exerted by the atmosphere - in STP)
P (final pressure) = ? (in atm)
- <u><em>We have an isothermal transformation, that is, its temperature remains constant, if the volume of the gas in the container decreases, so its pressure increases. Applying the data to the equation Boyle-Mariotte, we have:</em></u>






<u><em>Answer: </em></u>
<u><em>The new pressure of the gas is 2.11 atm </em></u>
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C. A lipid with three unsaturated fatty acids.
(got the question correct on a test)
<span>Among the given choices, the third option is the only one which illustrates single replacement.
(3)H2SO4 + Mg --> H2 + MgSO4
A single replacement is also termed as single-displacement reaction, a reaction by which an element in a compound, displaces another element.
It can be illustrated this way:
X + Y-Z → X-Z + Y</span>