Answer:
22×10⁻¹³
Explanation:
Scientific notation:
Scientific notation is the way to express the large value in short form.
The number in scientific notation have two parts.
The digits (decimal point will place after first digit)
× 10 ( the power which put the decimal point where it should be)
for example the number 6324.4 in scientific notation will be written as = 6.3244 × 10³
When we multiply or divide the values the number of significant figures must be equal to the less number of significant figures in given value. Thus, in given value,
(4.1357× 10⁻¹⁵) × (5.4×10²)
22×10⁻¹³
Answer:
[Acetic acid] = 0.07 M
[Acetate] = 0.13 M
Explanation:
pH of buffer = 5
pKa of acetic acid = 4.76
![pH=p_{Ka} + log\frac{[Salt]}{[Acid]}](https://tex.z-dn.net/?f=pH%3Dp_%7BKa%7D%20%2B%20log%5Cfrac%7B%5BSalt%5D%7D%7B%5BAcid%5D%7D)
Now using Henderson-Hasselbalch equation
![5=4.76 + log\frac{[Acetate]}{[Acetic\;acid]}](https://tex.z-dn.net/?f=5%3D4.76%20%2B%20log%5Cfrac%7B%5BAcetate%5D%7D%7B%5BAcetic%5C%3Bacid%5D%7D)
![log\frac{[Acetate]}{[Acetic\;acid]} = 0.24](https://tex.z-dn.net/?f=log%5Cfrac%7B%5BAcetate%5D%7D%7B%5BAcetic%5C%3Bacid%5D%7D%20%3D%200.24)
....... (1)
It is given that,
[Acetate] + [Acetic acid] = 0.2 M ....... (2)
Now solving both the above equations
[Acetate] = 1.74[Acetic acid]
Substitute the concentration of acetate ion in equation (2)
1.74[Acetic acid] + [Acetic acid] = 0.2 M
[Acetic acid] = 0.2/2.74 = 0.07 M
[Acetate] = 0.2 - 0.07 = 0.13 M
<u>Answer:</u>
<u>For a:</u> Yes, he has gained weight.
<u>For b:</u> The number of onions required is 1.
<u>Explanation:</u>
We are given:
Weight of Brandon checked earlier = 183 lb
Converting this into kilograms, we use the conversion factor:
1 kg = 2.205 lb
So, 
And, weight of Brandon measured at the health club = 85.0 kg
As, the weight at the health club is more than the previous measured weight. So, Brandon has gained weight.
We are given:
Amount of diced onions a recipe calls = 125 g
Mass of 1 onion = 4 oz
Converting the mass of 1 onion to ounces, we use the conversion factor:
1 oz = 28.35 g
So, 
To calculate the number of onions, we use the equation:


Hence, the number of onions required is 1.
Answer:
24%
Explanation:
From the question, the limiting reactant is H2S.
The reaction equation is;
2H2S + O2 → 2S + 2H2O
Number of moles of H2S reacted = 22g/34 g/mol = 0.647 moles
According to the reaction equation;
2 moles of H2S yields 2 moles of sulphur
0.647 moles of H2S yields 0.647 moles of sulphur
So;
Theoretical yield of sulphur = 0.647 moles * 32 g/mol = 20.7 g
Actual yield = 5 g
% yield = actual yield/theoretical yield * 100
% yield =5 g/20.7 g * 100
% yield = 24%
Answer:
The atomic mass of lead is: 207.216 u
Explanation:
data Isotopes mass percent
1 203.97302 1.4
2 205.974444 24.1
3 206.97587 22.1
4 207.97663 52.4
atomic mass = (203.97302x 0.014) + (205.974444 x 0.241) +
(206.97587 x 0.221) + (207.97663 x 0.524)
atomic mass = 2.856 +49.639 + 45.742 + 108.979
atomic mass = 207.216 u