<span>Actually, the heat of reaction hrxn s calculated by taking
the sum of the heats of formation of the products minus the sum of the heats of
formation of the reactants. However, at heat of formations of pure elements at
atmospheric conditions is zero, therefore the hf of N2 is not important since
it is zero anyway.</span>
Answer:
0.0014 moles is present in 40cm³ of 0.035M of HCl solution
Explanation:
Molarity = 0.035M
V = 40.0mL
1mL = 1cm³
V = 40cm³
0.035 moles = 1000cm³
X moles is present in 40cm³
X = (40 * 0.035) / 1000
X = 0.0014moles
0.0014 moles is present in 40cm³ of solution
C) They have a large number of rods and small number of cones.
<h2>~<u>Solution</u> :-</h2>
- Here, to find the atomic mass of element, we must;
We know that,
- 4.6 x $ \sf{10^{22}}$ atoms of an element weigh 13.8g.
Thus,
The atoms of $ \sf{ 6.02 \times 10^{13}}$ will weigh;
- Hence, the molar mass (atomic mass) will be <u>180.6 g.</u>
Aluminum atomic number 13 becomes Neon with an atomic number of 10 when it loses three valence electrons.