Answer: 1,260
Explanation: There are about 180 days in a school year. 7 hour school days x 180 about 1,260
i hope this helps
Over the ocean, the temperature rises much slower, because the water evaporates causing the hot molecules to go into the atmosphere, and the overall temperature of the water doesn't increase much, this causes the area without the water to be much hotter.
Answer: 0.8M
Explanation:
Given that,
Amount of moles of NaCl (n) = ?
Mass of NaCl in grams = 1.40 g
For molar mass of NaCl, use the molar masses:
Sodium, Na = 23g;
Chlorine, Cl = 35.5g
NaCl = (23g + 35.5g)
= 58.5g/mol
Since, amount of moles = mass in grams / molar mass
n = 1.40g / 58.5g/mol
n = 0.024 mole
Now, given that:
Amount of moles of NaCl (n) = 0.024
Volume of NaCl solution (v) = 30.0mL
[Convert 30.0mL to liters
If 1000 mL = 1L
30.0mL = 30.0/1000 = 0.03L]
Concentration of NaCl solution (c) = ?
Since concentration (c) is obtained by dividing the amount of solute dissolved by the volume of solvent, hence
c = n / v
c = 0.024 mole / 0.03 L
c = 0.8 M (0.8M means concentration is in moles per litres)
Thus, the concentration of the solution is 0.8M
Answer:
The percentage abundance of Eu isotopes are 52 % and 48 %
.
Explanation:
The formula for the calculation of the average atomic mass is:
Given that:
Since the element has only 2 isotopes, so the let the percentage of first be x and the second is 100 -x.
For first isotope,:
% = x %
Mass = 151.0 amu
For second isotope :
% = 100 - x
Mass = 153.0 amu
Given, Average Mass = 151.96 amu
Thus,
Solving for x, we get that:
x = 52 %
<u>Thus percentage abundance of Eu isotopes are 52 % and 48 %
.</u>
