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4 years ago

Which knowledge is radiometric dating based upon?

1 answer:

3 0

Geologists commonly use radiometric dating methods , based on the natural radioactive decay of certain elements such as potassium and carbon , as reliable clocks to date ancient events .

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Peppered moths come in two colors, black and white. What did Kettlewell show, with regard to peppered moth populations and tree

Vera_Pavlovna [14]

A is the answer because the trees turned blackish from the coal so moths that were black could camouflage on those trees easier.

4 0

4 years ago

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You have 500 mL of 5 M HCI already made. You need to dilute the solution to 1 M HCI. How much water will you need to add?

Strike441 [17]

Answer:

a. 2500 ml of water is needed

Explanation:

V1C1=V2C2

(500)(5)=(1)V2

2500/1=V2

2500 = v2

7 0

3 years ago

Aspirin is a weak organic acid whose molecular formula is HC9H7O4. An aqueous solution of aspirin is prepared by dissolving 3.60

garri49 [273]

Answer:

Ka = 3.50x10⁻⁴

Explanation:

First, we need to convert the unit of 3.60 g/L to mol/L:

$C_{C_{9}H_{8}O_{4}} = 3.60 \frac{g}{L}*\frac{1 mol}{180.16 g} = 0.0200 mol/L$

The reaction dissociation of aspirin in water is:

C₉H₈O₄ + H₂O ⇄ C₉H₇O₄⁻ + H₃O⁺

0.02 - x x x

The constant of the above reaction is:

$Ka = \frac{[C_{9}H_{7}O_{4}^{-}][H_{3}O^{+}]}{[C_{9}H_{8}O_{4}]}$

$Ka = \frac{x^{2}}{0.02 - x}$

To find Ka we need to find the value of x. We know that pH = 2.6 so:

$pH = -log[H_{3}O^{+}]$

$2.6 = -log(x)$

$x = 2.51 \cdot 10^{-3} M = [H_{3}O^{+}] = [C_{9}H_{7}O_{4}^{-}]$

Now, the concentration of C₉H₈O₄ is:

$C_{C_{9}H_{8}O_{4}} = 0.02 - 2.51 \cdot 10^{-3} = 0.018 M$

Finally, Ka is:

$Ka = \frac{[C_{9}H_{7}O_{4}^{-}][H_{3}O^{+}]}{[C_{9}H_{8}O_{4}]} = \frac{(2.51 \cdot 10^{-3})^{2}}{0.018} = 3.50 \cdot 10^{-4}$

Therefore, the Ka of aspirin is 3.50x10⁻⁴.

I hope it helps you!

3 0

3 years ago

The shininess of an element is also referred to as "metallic luster." which of the following elements is most likely to have a m

lisov135 [29]

The shininess of an element is also referred to as "metallic luster." The element that is most likely to have a metallic luster is B. rhodium.
Arsenic has a dull luster, chlorine and hydrogen are gases so they don't have luster.

4 0

3 years ago

Cells with nuclei belong in the domain Archaea Bacteria Eukarya Protists

svet-max [94.6K]

Eukarya cause all cells with nuclei are considered eukaryotic

5 0

4 years ago

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