Answer:
c and d are correct
Explanation:
In A, false because in Valence Electrons, the more the valences, the more stable an atom is.
In B, false because atoms cannot readily gain or lose valence electrons as the number of valence electrons is determined by the column they are in.
In C, true because the more the valence electrons, the more the stability of an atom.
In D, true as electron placing is important and the reactivity of an atom is important.
So C and D are true!
Answer:
A) 14. 25 × 10²³ Carbon atoms
B) 34.72 grams
Explanation:
1 molecule of Propane has 3 atoms of Carbon and 8 atoms of Hydrogen.
The sample has 3.84 × 10²⁴ H atoms.
If 8 atoms of Hydrogrn are present in 1 molecule of propane.
3.84 × 10²⁴ H atoms are present in

<u>= 4.75 × 10²³ molecules of Propane</u>.
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No. of Carbon atoms in 1 molecule of propane = 3
=> C atoms in 4.75× 10²³ molecules of Propane = 3 × 4.75 × 10²³
<u>= 14.25 × 10²³ </u>
<u>________________________________________</u>
<u>Gram</u><u> </u><u>Molecular</u><u> </u><u>Mass</u><u> </u><u>of</u><u> </u><u>Propane</u><u>(</u><u>C3H8</u><u>)</u>
= 3 × 12 + 8 × 1
= 36 + 8
= 44 g
1 mole of propane weighs 44g and has 6.02× 10²³ molecules of Propane.
=> 6.02 × 10²³ molecules of Propane weigh = 44 g
=> 4. 75 × 10²³ molecules of Propane weigh =



<u>= 34.72 g</u>
Answer:
The change in temperature that occurs when 8000 J of heat is used by a mass 75 g of water is 25.4 °C
Explanation:
H = mc ΔT
m = 75 g
c = 4. 200 J/ g °C
H = 8000 J
ΔT =?
Rearranging the formula, making ΔT the subject of formula;
ΔT = H / m c
ΔT = 8000 / 75 * 4.200
ΔT = 8000 / 315
ΔT = 25.4 °C