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2 years ago

8

What piece of equipment is used to measure: length

2 answers:

avanturin [10]2 years ago

8 0

Answer:

Ruler

Explanation:

Ruler and eraser kakgjwjeigidiifigig

kaheart [24]2 years ago

4 0

Vernier caliper like a pipe and wie

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What happens to air pressure as altitude increases

gulaghasi [49]

Answer:

the air pressure decreases

explanation

as altitude increases air pressure decreases the surface of the Earth is bottom of the ocean of the are the layer on top increase pressure so that sea levels a body is under 14.7 pounds of pressure per square inch moving up in altitude decreases weight of the air that causes the pressure

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3 years ago

Aspirin (acetylsalicylic acid, C9H8O4) is a weak monoprotic acid. To determine its acid-dissociation constant, a student dissolv

Triss [41]

Answer:

1. $3.57\times 10^{-4}$ was the $K_a$ value calculated by the student.

2. $5.93\times 10^{-4}$ was the $K_b$ of ethylamine value calculated by the student.

Explanation:

1.

The $pH$ value of Aspirin solution = 2.62

$pH=-\log[H^+]$

$[H^+]=10^{-2.62}=0.00240 M$

Moles of s asprin = $\frac{2.00 g}{180 g/mol}=0.01111 mol$

Volume of the solution = 0.600 L

The initial concentration of Aspirin = c = $\frac{0.01111 mol}{0.600 L}=0.0185 M$

$HAs\rightleftharpoons As^-+H^+$

initially

c 0 0

At equilibrium

(c-x) x x

The expression of dissociation constant :

$K_a=\frac{[As^-][H^+]}{[HAs]}$ :

$K_a=\frac{x\times x }{(c-x)}$

$=\frac{0.00240 M\times 0.00240 M}{(0.0185-0.00240 )}$

$K_a=3.57\times 10^{-4}$

$3.57\times 10^{-4}$ was the $K_a$ value calculated by the student.

2.

The $pH$ value of ethylamine = 11.87

$pH+pOH=14$

$pOH=14-11.87=2.13$

$pOH=-\log[OH^-]$

$[OH^-]=10^{-2.13}=0.00741 M$

The initial concentration of ethylamine = c = 0.100 M

$C_2H_5NH_2+H_2O\rightleftharpoons C_2H_5NH_3^{+}+OH^-$

initially

c 0 0

At equilibrium

(c-x) x x

The expression of dissociation constant :

$K_b=\frac{[C_2H_5NH_3^{+}][OH^-]}{[C_2H_5NH_2]}$ :

$K_b=\frac{x\times x}{(c-x)}$

$=\frac{0.00741\times 0.00741}{(0.100-0.00741)}$

$K_b=5.93\times 10^{-4}$

$5.93\times 10^{-4}$ was the $K_b$ of ethylamine value calculated by the student.

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2 years ago

Which of these is a characteristic of science? (5 points) Question 1 options: 1) It cannot be reproduced by any scientist. 2) It

Alex17521 [72]

Answer:

3

Explanation:

It is based on empirical evidence

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2 years ago

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Your answer is C. Both gasoline and litter would need to be physically separated from the water, because neither bonds with the water.

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Which organ produces the female hormone estrogen

worty [1.4K]

Answer:

Ovary

Explanation:

ovaries produce the most estrogen in females.

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2 years ago

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