Answer:
The correct answer is - 2.557 KJ
Explanation:
In this case, Hg is melting, the process is endothermic, so the energy change will have a positive sign.
we can calculate this energy by the following formula:
Q = met
where, m = mass,
e = specific heat
t = temperature
then,
Q = 78*0.14* (273-38.8)
here 0.14 = C(Hg)
= 2.557 Kj
Answer:
The answer is: +7
Explanation:
Oxidation state or oxidation number of an element is the hypothetical charge on an element that forms completely ionic bonds. The oxidation number represents the number of electrons lost or gained by that element.
Perchlorate ion is a molecule with a chemical formula: ClO₄⁻
The oxidation state of oxygen in ClO₄⁻ = -2,
the total charge on the ClO₄⁻ molecule = -1,
let the oxidation state of chlorine be x
<u><em>As the sum of oxidation states of all elements in a molecule is equal to the total charge on the molecule.</em></u>
⇒ oxidation state of chlorine + oxidation state of oxygen × 4 = total charge on the molecule
⇒ x + (-2) × 4 = -1
⇒ x + (-8) = -1
⇒ x = -1 + 8 = +7
⇒<u> </u><u>x = +7</u>
<u>Therefore, the oxidation state of chlorine in the perchlorate ion (ClO₄⁻): x = +7</u>
A) Heat.
Friction produces heat.
Answer:
3
Explanation:
Subscript basically tells you the number of element or ions present in a compound. In this case the subscript of carbon which is 3 denotes that only three carbon atoms is present in the compound.
