Answer: 0.4533mol/L
Explanation:
Molar Mass of CaCO3 = 40+12+(16x3) = 40+12+48 = 100g/mol
68g of CaCO3 dissolves in 1.5L of solution.
Xg of CaCO3 will dissolve in 1L i.e
Xg of CaCO3 = 68/1.5 = 45.33g/L
Molarity = Mass conc.(g/L) / molar Mass
Molarity = 45.33/100 = 0.4533mol/L
Answer:
C. 30.0 g NaOH and add water until the final solution has a volume of 3.00 L.
Explanation:
Molarity of a substance , is the number of moles present in a liter of solution .
M = n / V
M = molarity
V = volume of solution in liter ,
n = moles of solute ,
from the question ,
M = 0.250M
V = 3.00 L
M = n / V
n = M * v
n = 0.250M * 3.00 L = 0.75 mol
Moles is denoted by given mass divided by the molecular mass ,
Hence ,
n = w / m
n = moles ,
w = given mass ,
m = molecular mass .
From the question ,
n = 0.75 mol NaOH
m = molecular mass of NaOH = 40 g/mol
n = w / m
w = n * m
w = 0.75 mol * 40 g/mol = 30.0 g
Hence , by using 30.0 g of NaOH and dissolving it to make up the volume to 3 L , a solution of 0.250 M can be prepared .
It's an ionic bond! Potassium is a cation, or a metal with a positive charge, and fluoride is an anion, or a nonmetal with a negative charge.
A covalent bond is the bond between two nonmetals.
Hope this helped!
Half life is 15 hours
so 30 hours would be 2 half lives
after 15 hours it would be at 50%
after 15 more hours it would be at 50% of 50%
so .5 x .5 = .25
it would be 25%
