Answer:
true
Explanation:
when molecules of a solid substance is vibrating so, it means they are possessing average kinetic energy. thus, we can conclude that the statement all the molecules of a substance posses the average kinetic energy value is true.
<span>Important information to solve the exercise :
Substance ΔHf (kJ/mol):
HCl(g)= −92.0 </span><span>kJ/mol
Al(OH)3(s)= −1277.0 </span><span><span>kJ/mol
</span> H2O(l)= −285.8 </span><span>kJ/mol
AlCl3(s) =−705.6 </span><span>kJ/mol
</span><span>Al(OH)3(s)+3HCl(g)→AlCl3(s)+3H2O(l)
reactants products
products- reactants:</span><span>
(−705.6) + (3 x −285.8) - ( −1277.0 ) - (3 x −92.0 ) = - 10.0 </span>kJ per mole at 25°C
<span>
</span>
A line that stay s straight across the graph
<h2>
Answer: # of neutrons = 9</h2>
<h3>
Explanation:</h3>
# of neutrons = mass number - atomic number
= 17 - 8
= 9
<h3>∴ number of neutrons in an atom of oxygen of mass number 17, is 9.</h3>
Answer:
All the numbers in a chemical formula are significant, It is because the numbers in a chemical formula denote the number of different atoms present in the particular compound.
For example in H2SO4 there are 2 H 1 S and 4 O. This means 1 H2SO4 has 2 hydrogen 1 sulphur and 4 oxygen.