Answer:
The standard enthalpy of formation of HgO is -90.7 kJ/mol.
Explanation:
The reaction between Hg and oxygen is as follows.

From the given,
Molar mass of HgO = 216.59 g/mol
Mass of HgO decomposed = 18.5 g
Amount of heat absorbed = 7.75 kJ
From the reaction,
The standard enthalpy of formation = 
During the decomposition of 1 mol of HgO , 90.7 kJ of energy absorbed.
For the formation of 1 mol of HgO , 90.7 kJ of energy is release
Therefore, the enthalpy of formation of mercury(II)Oxide is -90.7 kJ/mol
Disaccharide forms when two monomers join.
Answer: 3 and 4 are the answers.
Explanation: i took the quiz.
When the concentrations of CO2 and H2CO3 are both horizontal lines then the rate of the forward reaction is the same as the rate of the reverse reaction.
<h3>What is rate of reaction?</h3>
The term rate of reaction refers to how fast or slow a reaction proceeds. Recall that the rate of reaction is measured from the rate of disappearance of reactants or the rate of appearance of products.
When the [CO2] and [H2CO3 ] are both horizontal lines, the rate of the forward reaction is the same as the rate of the reverse reaction.
Let us recall that the reaction is reversible hence addition of H2CO3 will increase the concentration of H2CO3, the reverse reaction would be favored.
Learn more about rate of reaction: brainly.com/question/8592296
Answer A
x-ray optical telescope.
hope this helps!.