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stepladder [879]
2 years ago
7

Plsssssss! help! 20 points

Chemistry
1 answer:
Evgen [1.6K]2 years ago
5 0

Answer:

Explanation:

molecular weight of N₂H₄ is as follows

2 x 14 + 4 x 1 = 32

so 32 gram of N₂H₄  is equal to one mole of N₂H₄

25 gram of  N₂H₄ will be equal to 25 / 32 mole of  N₂H₄

so numerical quantity needed to convert grams of  N₂H₄  to mole is

1 / 32 or .03125 . This number needs to be multiplied with grams of N₂H₄

to convert it to number of moles.

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Ka, the acid dissociation constant, for an acid is 9 × 10^{−4} at room temperature. At this temperature, what is the approximate
devlian [24]
Dissociation=k×no of moles
percentage of dissociation=9.0×10^-4×1×100
knowing that x%=x/100,we then say;
x/100=9.0×10^-4×1×100
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8 0
2 years ago
A sample taken from a layer of mica in a canyon has 2.10 grams of potassium-40. A test reveals it to be 2.6 billion years old. H
DanielleElmas [232]

Answer:

\boxed{ \text{8.40 g}} 

Explanation:

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After a second half-life, half of that amount (25 %) will remain, and so on.  

We can construct a table as follows:  

 No. of                                 Fraction

<u>half-lives</u>      <u>    t/yr      </u>       <u>Remaining</u>  

      0               0                          1

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      2              2.6                          ¼

      3              3.9                          ⅛

We see that after 2 half-lives, ¼ of the original mass remains.

Conversely, if two half-lives have passed, the original mass must have been four times the mass we have now.

Original  mass = 4 × 2.10 g = \boxed{ \text{8.40 g}}

7 0
2 years ago
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Answer:

Increase the concentration of the solution

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8 0
2 years ago
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Q = m x c x ΔT

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hope this helps
7 0
2 years ago
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const2013 [10]

Answer: Option (a) is the correct answer.

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5 0
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