Answer:
![[A]_0=0.400M](https://tex.z-dn.net/?f=%5BA%5D_0%3D0.400M)
Explanation:
Hello.
In this case, since the first-order reaction is said to be linearly related to the rate of reaction:
![r=-k[A]](https://tex.z-dn.net/?f=r%3D-k%5BA%5D)
Whereas [A] is the concentration of hydrogen peroxide, when writing it as a differential equation we have:
![\frac{d[A]}{dt} =-k[A]](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5BA%5D%7D%7Bdt%7D%20%3D-k%5BA%5D)
Which integrated is:
![ln(\frac{[A]}{[A]_0} )=-kt](https://tex.z-dn.net/?f=ln%28%5Cfrac%7B%5BA%5D%7D%7B%5BA%5D_0%7D%20%29%3D-kt)
And we can calculate the initial concentration of the hydrogen peroxide as follows:
![[A]_0=\frac{[A]}{exp(-kt)}](https://tex.z-dn.net/?f=%5BA%5D_0%3D%5Cfrac%7B%5BA%5D%7D%7Bexp%28-kt%29%7D)
Thus, for the given data, we obtain:
![[A]_0=\frac{0.321M}{exp(-2.54x10^{-4}s^{-1}*855s)}](https://tex.z-dn.net/?f=%5BA%5D_0%3D%5Cfrac%7B0.321M%7D%7Bexp%28-2.54x10%5E%7B-4%7Ds%5E%7B-1%7D%2A855s%29%7D)
Best regards!
Answer:
The answer to your question is V = 0.32 L
Explanation:
Data
Volume of NH₃ = ?
P = 3.2 atm
T = 23°C
mass of CaH₂ = 2.65 g
Balanced chemical reaction
6Ca + 2NH₃ ⇒ 3CaH₂ + Ca₃N₂
Process
1.- Convert the mass of CaH₂ to moles
-Calculate the molar mass of CaH₂
CaH₂ = 40 + 2 = 42 g
42 g ------------------ 1 mol
2.65 g -------------- x
x = (2.65 x 1)/42
x = 0.063 moles
2.- Calculate the moles of NH₃
2 moles of NH₃ --------------- 3 moles of CaH₂
x --------------- 0.063 moles
x = (0.063 x 2) / 3
x = 0.042 moles of NH₃
3.- Convert the °C to °K
Temperature = 23°C + 273
= 296°K
4.- Calculate the volume of NH₃
-Use the ideal gas law
PV = nRT
-Solve for V
V = nRT / P
-Substitution
V = (0.042)(0.082)(296) / 3.2
-Simplification
V = 1.019 / 3.2
-Result
V = 0.32 L
Answer:
0.297 mol/L
Explanation:
<em>A chemist prepares a solution of potassium dichromate by measuring out 13.1 g of potassium dichromate into a 150 mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mol/L of the chemist's potassium dichromate solution. Be sure your answer has the correct number of significant digits.</em>
<em />
Step 1: Calculate the moles corresponding to 13.1 g of potassium dichromate
The molar mass of potassium dichromate is 294.19 g/mol.
13.1 g × (1 mol/294.19 g) = 0.0445 mol
Step 2: Convert the volume of solution to L
We will use the relationship 1 L = 1000 mL.
150 mL × (1 L/1000 mL) = 0.150 L
Step 3: Calculate the concentration of the solution in mol/L
C = 0.0445 mol/0.150 L = 0.297 mol/L
Answer:
Subtract them.
Explanation:
''''"Since all number in scientific notation have base 10, we can always multiply them and divide them. To multiply two numbers in scientific notation, multiply their coefficients and add their exponents. To divide two numbers in scientific notation, divide their coefficients and subtract their exponents."""""
I was actually learned about this in school just found an source.
<span>Well it depends on percentage by what, but I'll just assume that it's percentage by mass.
For this, we look at the atomic masses of the elements present in the compound.
Cu has an atomic mass of 63.546 amu
Fe has 55.845 amu
and S has 36.065 amu
Since there are 2 molecules of Sulfur for each one of Cu and Fe, we'll multiply the Sulfur atomic weight by 2 to obtain 72.13 amu
So we have not established the mass of the compound in amus
63.546 + 55.845 + 72.13 = 191.521
That is the atomic mass of Chalcopyrite. and Iron's atomic mass is 55.845
So to get the percentage, or fraction of iron, we take 55.845 / 191.521
Which comes out to 29.15% by mass
Mass of the sample is not needed for this calculation, but since the question mentions it I would go ahead and check if the question isn't also asking for the mass of Iron in the sample as well, in which case you just find the 29.15% of 67.7g</span>
