Answer:
<h2>The answer is option A</h2>
Explanation:
The mass of a substance when given the density and volume can be found by using the formula
<h3>mass = Density × volume</h3>
From the question
volume of object = 7 cm³
density = 5 g/cm³
The mass of the object is
mass = 5 × 7
We have the final answer as
<h2>35 g</h2>
Hope this helps you
Hi,
The answer should be C.
Hope this helps, if you’d like further explanation please let me know.
This is your answer I hope it is right.
Answer: 480 kJ of energy is released when 3.5 mol of
reacts.
Explanation:
The balanced chemical reaction is:

Thus it is given that the reaction is exothermic (heat energy is released) as enthalpy change for the reaction is negative.
1 mole of
on reacting gives = 137 kJ of energy
Thus 3.5 moles of
on reacting gives =
of energy
Thus 480 kJ of energy is released when 3.5 mol of
reacts.