rewrite them and say them out loud or in your head repeatedly
Answer:
4:5
Explanation:
Let x represent the fraction of the mix that is hot water. Then the temperature of the mix is ...
60x +15(1-x) = 40·1
45x = 25 . . . . . . . . . subtract 15
x = 25/45 = 5/9 . . . divide by the coefficient of x
This is the fraction that is hot water, so the fraction that is cold water is ...
1-5/9 = 4/9
The ratio of cold to hot is ...
cold : hot = (4/9) : (5/9) = 4 : 5
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<em>Additional comments</em>
The problem assumes that the energy contained in a given mass of water is proportional to its temperature. That is almost true, sufficiently so that we can reasonably use that approximation.
If heat loss is figured into the problem, then additional information is needed regarding the energy content of water at temperatures in the range of interest. That is not provided by this problem statement, so we have ignored the heat loss.
I think it’s C.1/2 because the child could get five fingers like his mother or six fingers like his dad
Answer:
how can I solve this ?4Al+3O2 produce 2Al2O3 find a) oxygen atoms needed to react with 5.4 g of aluminium b) grams of oxygen needed to react with 0.6 mol of aluminium?
(A) n=m/M,
n(Al)=5.4/27=0.2 moles
n(O2)=n(Al)*3/4=0.2*3/4=0.15 moles
Number of oxygen atoms= n(O2)*Avogadro's number
=0.15*6.02*10^23=9.03*10^22 oxgyen atoms
(B)
n=m/M
n(Al)=0.6/27=0.02222 moles
n(O2)=n(Al)*3/4=0.016666 moles
m=n*M
m(O2)=0.0166666*32=0.53333 grams
There are 0.54 moles of sodium carbonate are contained by 57.3 grams of sodium carbonate.
we can calculate number of moles in a compound by dividing number of grams of compound by the molar mass of the compound.
molar mass of sodium carbonate = 105.987 g/mol
now, 57.3 / 105.987 = 0.54 moles
