Answer:
Explanation:
H3PO4(aq) + 3NaOH(aq) → Na3PO4(aq) + 3H2O(l)
mole of NaOH = 23.6 * 10 ⁻³L * 0.2M
= 0.00472mole
let x be the no of mole of H3PO4 required of 0.00472mole of NaOH
3 mole of NaOH required ------- 1 mole of H3PO4
0.00472mole of NaOH ----------x
cross multiply
3x = 0.0472
x = 0.00157mole
[H3PO4] = mole of H3PO4 / Vol. of H3PO4
= 0.00157mole / (10*10⁻³l)
= 0.157M
<h3>The concentration of unknown phosphoric acid is 0.157M</h3>
solution:
Weight of caffeine is W = 0.170 gm.
Volume of water is V= 10 ml
Volume of methylene chloride which extracted caffeine is v= 5ml
No of portions n=3
Distribution co-efficient= 4.6
Total amount of caffeine that can be unextracted is given by
![w_{n}=w\times[\frac{k_{Dx}v}{k_{Dx}v+v}]^n\\w_{3}=0.170[\frac{4.6\times10}{(4.6\times10+5)}]^3\\=0.170[\frac{46}{46+5}]^3\\=0.170[\frac{46}{51}]^3\\=0.170[\frac{97336}{132651}]\\=0.170\times0.734=0.125gms](https://tex.z-dn.net/?f=w_%7Bn%7D%3Dw%5Ctimes%5B%5Cfrac%7Bk_%7BDx%7Dv%7D%7Bk_%7BDx%7Dv%2Bv%7D%5D%5En%5C%5C%3C%2Fp%3E%3Cp%3Ew_%7B3%7D%3D0.170%5B%5Cfrac%7B4.6%5Ctimes10%7D%7B%284.6%5Ctimes10%2B5%29%7D%5D%5E3%5C%5C%3C%2Fp%3E%3Cp%3E%3D0.170%5B%5Cfrac%7B46%7D%7B46%2B5%7D%5D%5E3%5C%5C%3C%2Fp%3E%3Cp%3E%3D0.170%5B%5Cfrac%7B46%7D%7B51%7D%5D%5E3%5C%5C%3C%2Fp%3E%3Cp%3E%3D0.170%5B%5Cfrac%7B97336%7D%7B132651%7D%5D%5C%5C%3C%2Fp%3E%3Cp%3E%3D0.170%5Ctimes0.734%3D0.125gms)
amount of caffeine un extracted is 0.125gms
amount of caffeine extracted=0.170-0.125
=0.045 gms
Answer:
8.9 KJ
Explanation:
Given data:
Mass of strip = 251 g
Initial temperature = 22.8 °C
Final temperature = 75.9 °C
Specific heat capacity of granite = 0.67 j/g.°C
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 75.9 °C - 22.8 °C
ΔT = 53.1 °C
Q = 251 g × 0.67 j/g.°C × 53.1 °C
Q = 8929.8 J
Jolue to KJ.
8929.8J ×1 KJ / 1000 J
8.9 KJ
Answer:
9.69g
Explanation:
To obtain the desired result, first let us calculate the number of mole of N2 in 7.744L of the gas.
1mole of a gas occupies 22.4L at stp.
Therefore, Xmol of nitrogen gas(N2) will occupy 7.744L i.e
Xmol of N2 = 7.744/22.4 = 0.346 mole
Now let us convert 0.346 mole of N2 to gram in order to obtain the desired result. This is illustrated below:
Molar Mass of N2 = 2x14 = 28g/mol
Number of mole N2 = 0.346 mole
Mass of N2 =?
Mass = number of mole x molar Mass
Mass of N2 = 0.346 x 28
Mass of N2 = 9.69g
Therefore, 7.744L of N2 contains 9.69g of N2
Answer:
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Explanation:
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