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HACTEHA [7]
4 years ago
8

Surface water is found in oceans, lakes, reservoirs, streams, rivers,and glaciers. Lakes, rivers, and reservoirs are where human

s obtain most of the surface water they use. Aquifers are an underground source of water that humans also use.
Chemistry
1 answer:
ser-zykov [4K]4 years ago
7 0
Freshwater on the land surface is a vital part of the water cycle for everyday human life. On the landscape, freshwater is stored in rivers, lakes, reservoirs, and creeks and streams. Most of the water people use everyday comes from these sources of water on the land surface.
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8 0
2 years ago
At 20 ?C the vapor pressure of benzene (C6H6)is 75 torr, and that of toluene (C7H8) is 22 torr
tia_tia [17]

Answer:

(a) Benzene = 0.26; toluene = 0.74

(b) Benzene = 0.55

Explanation:

1. Calculate the composition of the solution

For convenience, let’s call benzene Component 1 and toluene Component 2.

According to Raoult’s Law,  

p_{1} = \chi_{1}p_{1}^{\circ}\\p_{2} = \chi_{2}p_{2}^{\circ}

where

p₁ and p₂ are the vapour pressures of the components above the solution

χ₁ and χ₂ are the mole fractions of the components

p₁° and p₂° are the vapour pressures of the pure components.

Note that

χ₁ + χ₂ = 1

So,  

\begin{array}{rcl}p_{\text{tot}} &=& p_{1} + p_{2}\\p_{\text{tot}} & = & \chi_{1}p_{1}^{\circ}  + (1 - \chi_{1})p_{2}^{\circ}\\36 & = & \chi_{1}\times 75  + (1 - \chi_{1}) \times 22 \\36 & = & 75\chi_{1} + 22 -22\chi_{1}\\14 & = & 53\chi_{1}\\\chi_{1} & = & \mathbf{0.26}\\\end{array}

χ₁ = 0.26 and χ₂ = 0.74

2. Calculate the mole fraction of benzene in the vapour

In the liquid,  

p₁ = χ₁p₁° = 0.26 × 75 mm = 20 mm

∴ In the vapour

\chi_{1} = \dfrac{p_{1}}{p_{\text{tot}} } = \dfrac{\text{20 mm} }{\text{36 mm}}  = 0.55

Note that the vapour composition diagram below has toluene along the horizontal axis. The purple line is the vapour pressure curve for the vapour. Since χ₂ has dropped to 0.45, χ₁ has increased to 0.55.

7 0
3 years ago
Identify the oxidizing agent and the reducing agent for mg(s)+fe2+(aq)→mg2+(aq)+fe(s). express your answers as chemical formulas
lara31 [8.8K]
Fe^2+ makes Mg go from 0 to 2+, Fe^2+ is the oxidizing, Mg makes Fe^2+ go from 2+ to 0, Mg is the reducing. 

Fe^2+ is a chemical symbol for ferrous in chemistry. Ferrous refers to iron with oxidation number of +2, denoted iron(II) or Fe2+.
Mg is a chemical symbol for Magnesium in chemistry.
6 0
3 years ago
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Water has a K, value of<br> 1x 10-13<br> 1x 10-10<br> 1x 10-15<br> 1x 10-14
Margaret [11]
K value of water is 1x 10^-14
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3 years ago
24.0 mL of a 0.120 M Ca(OH)2 solution is required to titrate 160 mL of an HCl solution to its equivalence point. Find the moles
Alex787 [66]
T<span>he balanced reaction is as follows;
Ca(OH)</span>₂<span> + 2HCl ---> CaCl</span>₂<span> + 2H</span>₂<span>O
  stoichiometry of Ca(OH)</span>₂<span> to HCl is 1:2
number of moles of Ca(OH)</span>₂<span> reacted = 0.120 mol/L x 0.0240 L = 0.00288 mol according to molar ratio of 1:2 number of HCl moles reacted = twice the number of Ca(OH)</span>₂<span> moles reacted
number of HCl moles reacted = 0.00288 mol x 2 = 0.00576 mol
number of HCl moles in 160 mL - 0.00576 mol
therefore number of HCl moles in 1000 mL - 0.00576 mol / 160 mL x 1000 mL = 0.036 mol
molarity of HCl = 0.036 M</span>
7 0
3 years ago
Read 2 more answers
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