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3 years ago

astronauts brought back 500 lb rock samples from the moon. how many kilograms did they bring back (1 kg = 2.20 lbs)

Chemistry

2 answers:

Mariana [72]3 years ago

6 0

500÷2.20=227.2727273kg

tigry1 [53]3 years ago

4 0

Astronauts brought back 500 lb of rock samples from the moon. How many kilograms did they bring back? (1 kg = 2.20 lb)

A. 500 kg

B. 1,100 kg

C. 498 kg

D. 227 kg

I believe it is D.

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What is true of the waste generated by nuclear power?

Nitella [24]

The correct answer is D) remains hazardous for a long time. Nuclear waste stays radioactive for many centuries.

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4 years ago

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Will Mark brainliest fro correct answer!!!! Please answer in the picture chemistry

tiny-mole [99]

Answer:

look at the graph

Explanation:

We know that as temperature increases, solubility increases.So, when there is a rise in temperature, as more solute become dissolved, the saturation point will be lifted and more amount of solute will be needed to reach saturation.

Here, when the temperature was 20oC, 38 g of salt was needed for saturation. As the temperature is increased by 15oC, at 35oC more amount of salt was needed to reach saturation(45g). So a 15oC rise in temperature caused a 7 g rise in the amount of salt needed for saturation. So, if temperature is increased additionally through 10oC, an approximate 4.5 g of salt will be needed more to reach the saturation. That is at 45oC, the amount of salt at saturation will be approximately 49.5 g.

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6 0

3 years ago

Purification of chromium can be achieved by electrorefining chromium from an impure chromium anode onto a pure chromium cathode

mylen [45]

Answer:

696 h

Explanation:

Let's consider the reduction of Cr³⁺.

Cr³⁺(aq) + 3e⁻ → Cr(s)

We can establish the following relations.

The molar mass of Cr is 52.0 g/mol.
1 mol of Cr is deposited when 3 moles of e⁻ circulate.
1 mole of e⁻ has a charge of 96468 c (Faraday's constant).
1 A = 1 c/s
1 h = 3600 s

How many hours will it take to plate 13.5 kg of chromium onto the cathode if the current passed through the cell is held constant at 30.0 A?

$13.5 \times 10^{3} gCr.\frac{1molCr}{52.0gCr} .\frac{3mol/e^{-} }{1molCr} .\frac{96468c}{1mol/e^{-}} .\frac{1s}{30.0c} .\frac{1h}{3600s} =696 h$

3 0

3 years ago

Consider the rate constants below. which would correspond to the highest order reaction? k = 8.79 x 102 ms–1 k = 4.46 x 10–1 m–1

Kipish [7]

When the order n of the reaction rate is determined by this formula:

rate = K * [A]^n

when we have the unit of rate M S^-1

and the unit of [A] M

So:

1- for k = 8.79 x 10^2 M S^-1 :

when the unit of K here is M S^-1

by substitution in rate formula:

M S^-1 = M S^-1 * M ^n

∴ M^n = 1

∴M^0 = 1

∴ this reaction rate is zero order reaction

2- when k = 4.46 x 10^-1 and has unit M-1 S-1:

by substitution in rate formula:

M S^-1 = M-1 S-1 * M^n

∴M^2 = M^n

∴n = 2 so this is the second order reaction

3- when K 2.35 x 10^6 and it's unit is S-1 :

So by substitution in rate formula:

M S^-1 = S^-1 * M^n

∴ M^n = M

∴ n = 1

So this is the first order reaction

4- when k = 1.88 x 10^-3 and its unit is M-2 S-1

by substitution in rate formula:

M S^-1 = M^-2 S^-1 * M^n

∴ M^n = M^3

∴ n = 3

∴ this is a third order reaction

from 1 & 2 & 3 & 4

so we can see that the correct answer is (4), K= 1.88 x 10^-3 M-2 S-1 is the highest order reaction.

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3 years ago

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ladessa [460]

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3 years ago