Answer: -
3.151 M
Explanation: -
Let the volume of the solution be 1000 mL.
At 25.0 °C, Density = 1.260 g/ mL
Mass of the solution = Density x volume
= 1.260 g / mL x 1000 mL
= 1260 g
At 25.0 °C, the molarity = 3.179 M
Number of moles present per 1000 mL = 3.179 mol
Strength of the solution in g / mol
= 1260 g / 3.179 mol = 396.35 g / mol (at 25.0 °C)
Now at 50.0 °C
The density is 1.249 g/ mL
Mass of the solution = density x volume = 1.249 g / mL x 1000 mL
= 1249 g.
Number of moles present in 1249 g = Mass of the solution / Strength in g /mol
= 
= 3.151 moles.
So 3.151 moles is present in 1000 mL at 50.0 °C
Molarity at 50.0 °C = 3.151 M
Answer:
13.33 g/dm³
Explanation:
Concentration (g/dm³)= mass(g) ÷ volume (dm³)
Now you need to convert 150 cm³ to dm³
1000cm³ = 1 dm³
thus, 150 cm3= 150 ÷ 1000
= 15dm³
and you already have mass in grams
so concentration = 2 ÷ 0.15
= 13.33 g/dm³ and there you go.. solved ;)
<span>The student is incorrect because helium has 2 valence electrons and it's in group 18 because the first energy level is full. Although helium is placed in Group 18 which generally has 8 valence electrons, it does not have 8 valence electrons as the student suggested. It was grouped together with the noble gases because it exhibits similar properties with them. </span>
The exponential is 3.007 times 10 to the -5
M/V=D
16.52/2.26=D
Density=6.86 g/cm^3
