mass * temp change * specific heat
make sure the specific heat value is in Joules
The correct answer should be D. can be real or virtual depending on the object's placement
Depending on the position on the mirror, it can be determined whether the object is real or virtual.
Answer:
given an element U of relative atomic mass 10.8 for example with isotopes U-10 and U-11 we can get their percentages by the following steps.
Explanation:
1:let the Percentage of U-10 equal to X% and percentage of U-11equal to Y%.
2:The addition of X% and Y% equal to 100%.
3:X%=100%-Y%
4:X% of U-10 +Y% of U-11=10.8
5: substitute 3 in 4.
6: i.e (100-Y)% of U-10+Y% of U-11=10.8.
7:(100-Y)/100 of 10 +Y/100 of 11=10.8.
8:100-Y/10 +11Y=10.8.
9:(1000-10Y+11Y)/100=10.8.
10:1000+Y=10.8*100
11:1000+Y=1080.
12:Y=1080-1000.
13:Y=80.
14: from 3,X=100%-Y%.
X=100%-80%=20%.
15: Therefore, the percentage of isotopes in the isotopic mixture are 20% U-10 and 80% U-11.
Answer:
a) CaF₂.
b) 7.81g of CaF₂ are present.
Explanation:
a) The calcium ion has as charge Ca²⁺ and fluoride ion is F⁻, that means formula unit is:
CaF₂
b) 1 molecule of CaF₂ contains 2 anions, F⁻. Thus, the moles of CaF₂ is:
1.2x10²³ anions * (1 moleculeCaF₂ / 2 anions) = 6x10²² molecules of CaF₂
6.022x10²³ molecules = 1mol:
6x10²² molecules of CaF₂ * (1mol / 6.022x10²³molecules) = 0.10 moles CaF₂.
1 mole of CaF₂ has a mass of 78.07g:
0.10 moles CaF₂ * (78.07g / mol) =
7.81g of CaF₂ are present