Answer:
the symbol of an iron is Fe (ferous, feric).
Answer:
.
Explanation:
Acid = solution that split to H+ or H3O+ pH <7
The compound that can't split to H+ doesn't act as acid.
Answer:

Explanation:
In this problem, we need to convert
to km².
We know that,
1 km = 1000 m
⇒ 1 km² = 10⁶ m²
So,

So,
is equal to
.
Answer: 250 kJ
Explanation: According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to Hess’s law, the chemical equation can be treated as algebraic expressions and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
(1)
(2)
Net chemical equation:
(3)
Adding 1 and 2 we get,
(4)
Now dividing equation (4) by 4, we get
(4)
Answer:
question 6: winter solstice
question 7: rotation is when an object spins around its axis, revolution is when an object travels in a path around another
question 8: the rotational period is equal to the period of revolution for the moon
question 10: true