Each element or compound has a molar mass, which is calculated by multiplying the atomic mass of each element by the amount of atoms of that element, and summing the results of each element. The molar mass is measured in g/mol. So you divide the mass in grams by the molar mass to get the amount of moles.
Example:
There are 5g of water.
Calculate the amount of moles.
The water's formula is H2O, so the molar mass of it is
g/mol.
The amount of moles is:
5g ÷ 18g/mol ~ 0.28mol
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
SiO2 is the only possible choice because the other formulas contain metals. how do we know this? because the other formulas contain elements located on the left of the “staircase” on the periodic table that separates metals from non-metals.
Answer:
15m
Explanation:
vi = 0
vf = 10
a = -9.8
10^2 = 0 + 2(-9.8)(x2-x1) = -5.1
20-5.1 = 14.9m = 15m
Answer:
The new temperature of the water bath 32.0°C.
Explanation:
Mass of water in water bath ,m= 8.10 kg = 8100 g ( 1kg = 1000g)
Initial temperature of the water = 
Final temperature of the water = 
Specific heat capacity of water under these conditions = c = 4.18 J/gK
Amount of energy lost by water = -Q = -69.0 kJ = -69.0 × 1000 J
( 1kJ=1000 J)
The new temperature of the water bath 32.0°C.
