Answer:
Total amount of alum lost = 0.5122 grams
Explanation:
Let the total volume of the solution be 100 mL
In 100 mL of solution, there is 2.63 gram of alum.
Out of this 100 mL solution, 42.5 mL is remaining.
Amount of alum in 42.5 mL solution is
grams
Now the amount of alum lost is 
grams
Energy cannot be destroyed or created. Electricity is a form of energy which has to be created from other forms of energy. We have to pay for the creation of electricity because it requires certain resources to transform other energies into electricity.
This is false, all non metals have different physical properties.
Answer:
65.4%
Explanation:
The redox reaction is a 1:1:1 reaction because the reagents suffer a double displacement reaction, and the substance that is substituted have the same charge (H+ and Br-), thus, we first need to know which of the reagents is the limiting.
Let's test the 4-nitrobenzaldehyde as the limiting. The mass needed for sodium borohydride (m) is the mass given of 4-nitrobenzaldehyde multiplied by the stoichiometric mass of sodium borohydride divided by the stoichiometric mass of 4-nitrobenzaldehyde. The stoichiometric mass is the number of moles in the stoichiometric representation (1:1:1) multiplied by the molar mass, so:
m = (4.13 * 37.83*1)/(151.12*1)
m = 1.034 g
So, the mass needed of the other reagent is larger than the mass that was given, so, it will be the limiting, and the stoichiometric calculus must be done with it.
The mass of the product that was expected is then:
m = (0.700*153.14*1)/(37.83*1)
m = 2.83 g
The percent yield is the mass that was formed divided by the expected mass, and then multiplied by 100%:
%yield = (1.85/2.83)*100%
%yield = 65.4%
2 H2 + O2 ----------- 2 H2O
2 mol H2 ----------- 1 mol O2
27.4 mol H2- ------ x mol O2
2x = 27.4
x = 27.4 / 2
x = 13.7 moles O2
answer b
hope this helps!.
