Answer:
<em>the <u>valency of an element</u> is its combining capacity that is the number of electrons it requires to lose, gain or share in order to become neutral.</em>
[ An element can become neutral if it completes it's octet. That is if an element has 8 electrons in it'd outermost shell then it is considered neutral ]
- The valence of Magnesium is 2 because it requires to lose 2 electrons to become neutral.
- whereas, the valence of Oxygen is 2 because it needs to gain 2 electrons to become stable.
Hence they both have the same valence.
One may say that oxygen's valence is -2 while that of Magnesium is + 2. It's meaning is still the same but "-" sign indicates that oxygen will be gaining electrons in the process of becoming stable.
the mass of ice taken = 10 g
the mass of water = 250 g
initial temperature of water = 20 C
the final temperature of water = 16. 8 C
specific heat of water = 4.18 J/g*K
the heat absorbed by ice to melt = heat loss by water
heat loss by water = mass X specific heat of water X change in temperature
heat loss by water = 250 X 4.18 X (20-16.8) = 3344 Joules
heat gained by ice = 3344 J
heat gained by ice = enthalpy of fusion X moles of ice
moles of ice = mass / molar mass = 10 / 18 = 0.56 moles
enthalpy of fusion = 3344 / 0.56 = 5971.43 J / mole
Answer:

Explanation:
Hello,
In this case, we are asked to compute the by mass percent for the given 3.2 g of ethylene glycol in 43.5 g of water. In such a way, since the by mass percent is computed as follows:

Whereas the solute is the ethylene glycol and the solvent the water, therefore we obtain:

Best regards.
Answer:
It would be 3 times as much gravity or 7 times
Explanation: