Answer with Explanation:
A candle relights when a match is held above the wick because its trail of smoke still contains some of the wax. When candles are burned, the heat of the flame turns the the wax (which is originally solid) into liquid (commonly near the wick) and then evaporates as gas. The vaporized wax actually protect the wick and this is the reason why it is not burned. So, when you put off a candle, the vaporized wax is still present near the wick. This, remember, holds heat and light energy. Thus, this explains why the candle can be relighted once you hold a match above the wick. It then allows the match to ignite.
Thus, this explains the answer.
Explanation of the strategy: 1) calculate the mass of water and convert to number of moles, 2) convert the mass of anhydrous CuSO4 to moles, and, 3)calculate the mole ratio of water to CuSO4 anhydrous
1) Calculate the mass of water:
mass of water = mass of the hydrate CuSO4 - mass of the anhydrous compound
mass of water = 12.98 g - 9.70 g = 3.28g
2) Calculate the number of moles of water
number of moles = mass in grams / molar mass
molar mass of water = 18.01 g/mol
number of moles of water = 3.28 g / 18.01 g/mol = 0.182 mol
3) Calculate the number of moles of CuSO4 anhydrous
number of moles = mass in grams / molar mass
molar mass of Cu SO4 = 159.6 g/mol
number of moles of CuSO4 = 9.70g / 159.6 g/mol = 0.0608 moles
4) Calculate the ratio moles of water / moles of CuSO4
ratio = moles of water / moles of CuSO4 = 0.182 / 0.0608 = 2.99 ≈ 3
Therefore the molecular formula is CuSO4 . 3H2O
Name: copper(II) sulfate trihydrate.
A corn oil. Because oil is treated with a solvent. After that it is refined which gets rid of free fatty acids. Finally, it is sent through steam distillation to get rid of volatile organic compounds.
Answer:
(E) changing temperature
Explanation:
Consider the following reversible balanced reaction:
aA+bB⇋cC+dD
If we know the molar concentrations of each of the reaction species, we can find the value of Kc using the relationship:
Kc = ([C]^c * [D]^d) / ([A]^a * [B]^b)
where:
[C] and [D] are the concentrations of the products in the equilibrium; [A] and [B] reagent concentrations in equilibrium; already; b; c and d are the stoichiometric coefficients of the balanced equation. Concentrations are commonly expressed in molarity, which has units of moles / 1
There are some important things to remember when calculating Kc:
- <em>Kc is a constant for a specific reaction at a specific temperature</em>. If you change the reaction temperature, then Kc also changes
- Pure solids and liquids, including solvents, are not considered for equilibrium expression.
- The reaction must be balanced with the written coefficients as the minimum possible integer value in order to obtain the correct value of Kc
