Answer: 255 pm
Explanation: Hope this helps!
The balanced chemical equation for reaction of and is as follows:
From the balanced chemical equation, 2 mol of reacts with 1 mol of .
First calculating number of moles of as follows:
On rearranging,
Here, M is molarity and V is volume. The molarity of is given 0.274 M or mol/L and volume 155 mL, putting the values,
Since, 1 mol of reacts with 2 mol of thus, number of moles of will be .
Now, molarity of is given 0.305 M or mol/L thus, volume can be calculated as follows:
Therefore, volume of is 278.5 mL.
The model of photosynthesis used by biologists begins when chlorophyll splits a water molecule into hydrogen and oxygen. The oxygen from the water is a waste product that is released as a gas. In later stages of photosynthesis, carbon dioxide from the air and hydrogen from the water unite to form glucose. Photosynthesis usually takes place in the leaves of green plants. The food produced is a simple sugar called glucose. Some of the food made during photosynthesis is used by plants for their growth and development. The rest is stored in the plant.
Answer: 61%
The reaction equation should be
CaF2 + H2SO4 → 2HF + CaSO4
For every 1 molecule CaF2 used, there will be 2 molecules of HF formed. The molecular mass of CaF2 is 78/mol while the molecular mass of HF is 20g/mol. If the yield is 100%, the amount of HF formed by 112g CaF2 would be: 112g/(78g/mol) * 2 * (20g/mol)=57.43g
The percentage yield of the reaction would be: 35g/57.43g= 60.94%
The base dissociation constant or Kb is a value used to measure
the strength of a specific base in solution. To determine the percent ionization
of the substance we make use of the Kb given. Methylamine or CH3NH2 when
in solution would form ions:
CH3NH2 + H2O < = > CH3NH3+ + OH-
Kb is expressed as follows:
<span>
Kb = [OH-] [CH3NH3+] / [CH3NH2]
Where the terms represents the concentrations of the acid and the ions.
By the ICE table, we can calculate the equilibrium concentrations,
CH3NH2 CH3NH3+
OH-
I 1.60 0
0
C -x +x
+x
--------------------------------------------------
E 1.60-x x
x
Kb = [OH-] [CH3NH3+] / [CH3NH2] = </span> 3.4×10−4
<span> 3.4×10−4</span> = x^2 / 1.60-x
Solving for x,
x = [OH-] = 0.023 M
pH = 14 + log 0.023 = 12.36
Therefore, the first option is the closest one.