Answer:
Volcano
Explanation:
this is because Volcanoes erupt and the molten lava hardens and builds up to make land masses
First, we can neglect the Ka2 value and use Ka1:
according to this equation and by using the ICE table:
H2Se ⇄ H+ +HSe-
initial 0.4 M 0 0
change -X +X +X
Equ (0.4-X) X X
so,
Ka1 = [H+][HSe-] / [H2Se]
so by substitution:
1.3 x 10^-4 = X*X / (0.4 -X) by solving for X
∴X = 0.00715
∴[H+] = 0.00715 m
∴PH = -㏒[H+]
= -㏒ 0.00715
= 2.15
The answer is: " 56 g CaCl₂ " .
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Explanation:
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2.0 M CaCl₂ = 2.0 mol CaCl₂ / L ;
Since: "M" = "Molarity" (measurement of concentration);
= moles of solute per L {"Liter"} of solution.
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Note the exact conversion: 1000 mL = 1 L .
Given: 250 mL ;
250 mL = ? L ? ;
250 mL * (1 L / 1000 L) = (250/1000) L = 0.25 L .
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(2.0 mol CaCl₂ / L ) * (0.25L) = (2.0) * (0.25) mol = 0.50 mol CaCl₂ ;
We have: 0.50 mol CaCl₂ ; Convert to "g" (grams):
→ 0.50 mol CaCl₂ .
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1 mol CaCl₂ = ? g ?
From the Periodic Table of Elements:
1 mol Ca = 40.08 g
1 mol Cl = <span>35.45 g .
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There are 2 atoms of Cl in " CaCl₂ " ;
→ Note the subscript, "2", in the " Cl₂ " ;
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So, to calculate the molar mass of "CaCl₂" :
40.08 g + 2(35.45 g) =
40.08 g + 70.90 g = 110.98 g ; round to 4 significant figures;
→ round to 111 g/mol .
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So:
→ 0.50 mol CaCl₂ = ? g CaCl₂ ? ;
→ 0.50 mol CaCl₂ * (111 g CaCl₂ / mol CaCl₂) ;
= (0.50) * (111 g) CaCl₂ ;
= 55.5 g CaCl₂ ;
→ round to 2 significant figures;
→ 56 g CaCl₂ .
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The answer is: " 56 g CaCl₂ " .
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Spontaneous is no spontaneous
Answer:

Explanation:
Mass and weight are quite different terms .
Weight is defined as the amount of force exerted on the earth due to our mass and gravity of acceleration.

Given that the mass is 90 kg and gravity of acceleration of earth is 9.82 m/s^2.
So weight will be

So this is the weight of the 90kg man standing on earth.