Explanation of the strategy: 1) calculate the mass of water and convert to number of moles, 2) convert the mass of anhydrous CuSO4 to moles, and, 3)calculate the mole ratio of water to CuSO4 anhydrous
1) Calculate the mass of water:
mass of water = mass of the hydrate CuSO4 - mass of the anhydrous compound
mass of water = 12.98 g - 9.70 g = 3.28g
2) Calculate the number of moles of water
number of moles = mass in grams / molar mass
molar mass of water = 18.01 g/mol
number of moles of water = 3.28 g / 18.01 g/mol = 0.182 mol
3) Calculate the number of moles of CuSO4 anhydrous
number of moles = mass in grams / molar mass
molar mass of Cu SO4 = 159.6 g/mol
number of moles of CuSO4 = 9.70g / 159.6 g/mol = 0.0608 moles
4) Calculate the ratio moles of water / moles of CuSO4
ratio = moles of water / moles of CuSO4 = 0.182 / 0.0608 = 2.99 ≈ 3
Therefore the molecular formula is CuSO4 . 3H2O
Name: copper(II) sulfate trihydrate.
Answer:
speed=5cm/minute
Explanation:
Given at 2:00PM the hermit is at 10cm mark
Also given that the hermit reaches 60cm mark at 2:10PM
Therefore the time elapsed is 10 minutes = 
the distance travelled by the hermit is 60-10=50cm=0.5m
We know that
speed = 
m/sec=5cm/minute
Answer:
22.73s
Explanation:
The reaction is a second order reaction, we know this by observing the unit of the slope.
rate constant = k = 0.056 M-1s-1
the initial concentration of BrO- [A]o = 0.80 M
time = ?
Final concentration [A]t= one-half of 0.80 M = 0.40M
1 / [A]t = kt + 1 / [A]o
1 / 0.40 = 0.056 * t + 1 / 0.80
t = (2.5 - 1.25) / 0.056
t = 22.73s
When the Pka for formic acid = 3.77
and Pka = -㏒ Ka
3.77 = -㏒ Ka
∴Ka = 1.7x10^-4
when Ka = [H+][HCOO-}/[HCOOH]
when we have Ka = 1.7x10^-4 &[HCOOH] = 0.21 m
so by substitution: by using ICE table value
1.7x10^-4 = X*X / (0.21-X)
(1.7x10^-4)*(0.21-X) = X^2 by solving this equation for X
∴X = 0.0059
∴[H+] = 0.0059
∴PH= -㏒ [H+]
= -㏒ 0.0059
= 2.23
