Answer:
r = 3.61x
M/s
Explanation:
The rate of disappearance (r) is given by the multiplication of the concentrations of the reagents, each one raised of the coefficient of the reaction.
r = k.![[S2O2^{-8} ]^{x} x [I^{-} ]^{y}](https://tex.z-dn.net/?f=%5BS2O2%5E%7B-8%7D%20%5D%5E%7Bx%7D%20x%20%5BI%5E%7B-%7D%20%5D%5E%7By%7D)
K is the constant of the reaction, and doesn't depends on the concentrations. First, let's find the coefficients x and y. Let's use the first and the second experiments, and lets divide 1º by 2º :
![\frac{r1}{r2} = \frac{0.018^{x} x0.036^{y} }{0.027^xx0.036^y}](https://tex.z-dn.net/?f=%5Cfrac%7Br1%7D%7Br2%7D%20%3D%20%5Cfrac%7B0.018%5E%7Bx%7D%20x0.036%5E%7By%7D%20%7D%7B0.027%5Exx0.036%5Ey%7D)
![\frac{2.6x10^{-6}}{3.9x10^{-6}} = (\frac{0.018}{0.027})^xx(\frac{0.036}{0.036})^y](https://tex.z-dn.net/?f=%5Cfrac%7B2.6x10%5E%7B-6%7D%7D%7B3.9x10%5E%7B-6%7D%7D%20%3D%20%28%5Cfrac%7B0.018%7D%7B0.027%7D%29%5Exx%28%5Cfrac%7B0.036%7D%7B0.036%7D%29%5Ey)
![0.67 = 0.67^x](https://tex.z-dn.net/?f=0.67%20%3D%200.67%5Ex)
x = 1
Now, to find the coefficient y let's do the same for the experiments 1 and 3:
![\frac{r1}{r3} = \frac{0.018x0.036^y}{0.036x0.054^y}](https://tex.z-dn.net/?f=%5Cfrac%7Br1%7D%7Br3%7D%20%3D%20%5Cfrac%7B0.018x0.036%5Ey%7D%7B0.036x0.054%5Ey%7D)
![\frac{2.6x10^{-6}}{7.8x10^{-6}} = (\frac{0.018}{0.036})x(\frac{0.036}{0.054})^y](https://tex.z-dn.net/?f=%5Cfrac%7B2.6x10%5E%7B-6%7D%7D%7B7.8x10%5E%7B-6%7D%7D%20%3D%20%28%5Cfrac%7B0.018%7D%7B0.036%7D%29x%28%5Cfrac%7B0.036%7D%7B0.054%7D%29%5Ey)
![0.33 = 0.5x 0.67^y](https://tex.z-dn.net/?f=0.33%20%3D%200.5x%200.67%5Ey)
![0.67 = 0.67^y](https://tex.z-dn.net/?f=0.67%20%3D%200.67%5Ey)
y = 1
Now, we need to calculate the constant k in whatever experiment. Using the first :
![2.6x10^{-6} = kx0.018x0.036](https://tex.z-dn.net/?f=2.6x10%5E%7B-6%7D%20%3D%20kx0.018x0.036)
![kx6.48x10^{-4} = 2.6x10^{-6}](https://tex.z-dn.net/?f=kx6.48x10%5E%7B-4%7D%20%3D%202.6x10%5E%7B-6%7D)
k = 4.01x10^{-3} M^{-1}s^{-1}[/tex]
Using the data given,
r = ![4.01x10^{-3}x1.8x10^{-2}x5.0x10^{-2}](https://tex.z-dn.net/?f=4.01x10%5E%7B-3%7Dx1.8x10%5E%7B-2%7Dx5.0x10%5E%7B-2%7D)
r = 3.61x
M/s
Answer:
Chemical change :has change in mass, heat is needed, new element is formed, hard to reverse.......
Physicalchange:does not have change in mass, heat is not necessary, no new element is formed, easy to reverse
Answer:
23.34 %.
Explanation:
- The percentage of water must be calculated as a mass percent.
- We need to find the mass of water, and the total mass in one mole of the compound. For that we need to use the atomic masses of each element and take in consideration the number of atoms of each element in the formula unit.
- <em>Atomic masses of the elements:</em>
Cd: 112.411 g/mol, N: 14.0067 g/mol, O: 15.999 g/mol, and H: 1.008 g/mol.
- <em>Mass of the formula unit:</em>
Cd(NO₃)₂•4H₂O
mass of the formula unit = (At. mass of Cd) + 2(At. mass of N) + 10(At. mass of O) + 8(At. mass of H) = (112.411 g/mol) + 2(14.0067 g/mol) + 10(15.999 g/mol) + 8(1.008 g/mol) = 308.5 g/mol.
- <em> Mass of water in the formula unit:</em>
<em>mass of water</em> = (4 × 2 × 1.008 g/mol) + (4 × 15.999 g/mol) = 72.0 g/mol.
- <em>So, the percent of water in the compound = [mass of water / mass of the formula unit] × 100 = [(72.0 g/mol)/(308.5 g/mol)] × 100 = 23.34 %</em>
Answer:
b, its a polymer that translates genetic information.
Carbon is found in oil and gas.
Aluminum a light metal used in making pots and pans.
Bromine is used in photography.