<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)
I think answer is
C. Something that can be observed or measured while changing the identity of the substance
Answer:
Explanation:
Empirical formula of ionic compound formed by two ions 
and 
is 
(for 
) of AB (for x = y)
The above empirical formula is in accordance with charge neutrality principle
Here each cation (
and 
) can form two ionic compounds by combining with two given anions (
and 
).
So the four ionic compounds are:
Answer:
Hydrogen: -141 kJ/g
Methane: -55kJ/g
The energy released per gram of hydrogen in its combustion is higher than the energy released per gram of methane in its combustion.
Explanation:
According to the law of conservation of the energy, the sum of the heat released by the combustion and the heat absorbed by the bomb calorimeter is zero.
Qc + Qb = 0
Qc = -Qb [1]
We can calculate the heat absorbed by the bomb calorimeter using the following expression.
Q = C . ΔT
where,
C is the heat capacity
ΔT is the change in the temperature
<h3>Hydrogen</h3>
Qc = -Qb = -C . ΔT = -(11.3 kJ/°C) . (14.3°C) = -162 kJ
The heat released per gram of hydrogen is:
<h3>Methane</h3>
Qc = -Qb = -C . ΔT = -(11.3 kJ/°C) . (7.3°C) = -82 kJ
The heat released per gram of methane is:
