0.000132 g of hydrated sodium borate (Na₂B₄O₇ · 10 H₂O)
Explanation:
First we need to find the number of moles of sodium borate (Na₂B₄O₇) in the solution:
molar concentration = number of moles / volume (L)
number of moles = molar concentration × volume (L)
number of moles of Na₂B₄O₇ = 0.1 × 0.5 = 0.05 moles
We know now that we need 0.05 moles of hydrated sodium borate (Na₂B₄O₇ · 10 H₂O) to make the solution.
Now to find the mass of hydrated sodium borate we use the following formula:
number of moles = mass / molar weight
mass = number of moles × molar weight
mass of hydrated sodium borate = 0.05 / 381 = 0.000132 g
Learn more about:
molar concentration
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Answer:
7.5 M
Explanation:
In order to find a solution's molar concentration, or molarity, you need to determine how many moles of solute, which in your case is sodium sulfate,
Na
2
SO
4
, you get in one liter of solution.
That is how molarity was defined -- the number of moles of solute in one liter of solution.
So, you know that you have
0.090
moles of solute in
12 mL
of solution. Your goal here will be to scale up this solution by using this information as a conversion factor to help you determine the number of moles of solute present in
Answer:
A reaction is non-spontaneous at any temperature when the Gibbs free energy > 0.
Explanation:
There is a state function, that determines if a reaction is sponaneous or non spontaneous:
ΔG = Gibbs free energy
A reaction is non spontaneous when it does require energy to produce that reaction. It will be spontaneous, when the reaction does not require energy to be occured.
The formula is: ΔG = ΔH - T.ΔS
ΔH → Enthalpy → Energy gained or realeased as heat.
ΔH < 0 → <em>Exothermic reaction. Spontaneity is favored
</em>
T → Temperature
ΔS → Entropy → Degree of disorder of a system.
When the system has a considered disorder ΔS > 0, disorder increases.
When the system is more ordered, ΔS < 0, disorder decreases.
The reaction will be non spontaneous if, the enthalpy is positive (endothermic reaction) and the ΔS < 0 (disorder decreases). It will not occur if we do not give energy.
ΔG < 0 → Spontaneous reaction
ΔG > 0 → Non spontaneous reaction
ΔG = 0 → System in equilibrium
Answer:
29.92grams of PbSO4
Explanation:
lead (iV) oxide = PbO2 = Molar mass: 239.2 g/mol
lead (ll) sulfate = PbSO4 = Molar mass: 303.26 g/mol
PbO2 = PbSO4
1:1 ratio
Pb = Lead
Lead has an oxidation number of 4+
O = Oxygen
Oxygen has an oxidation number of 2-
PbO2 + 4H+ + SO4 2- + 2e- = PbSO4(s) + 2H2O
Ok so the above would be the likely complete reaction, though we don't really need this as we already know the ratio is 1:1.
23.6g of PbO2
23.6/239.2 = 0.09866 Moles of PbO2
Since we have a 1:1 ratio we know that the same number of moles of PbSO4 are produced and since we know the molar mass it's simply molar mass multiplied by number of moles.
303.26 x 0.09866 = 29.92grams of PbSO4
