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3 years ago

15

Could you help answer these two question

1 answer:

Katen [24]3 years ago

4 0

Answer:

number 29 is D

Explanation: When the moon orbits the earth some of the light reflects off the moon, making it visible on the Earth.

I dont know how to answer 28 fully, is there a picture?

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. Using the following equation: F = ma Solve for m (1 point)

Oksanka [162]

<span>To solve for m in the equation F = ma, you must divide both side of the equation by a. This will make the equation look like F/a = ma/a. Since m is being multiplied by a, dividing it will cancel out. Now making the final equation look like F/a=m and/or m=F/a.</span>

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3 years ago

(a) Calculate the density of a 374.5-g sample of copper if it has a volume of 41.8 cm3. (b) A student needs 15.0 g of ethanol fo

o-na [289]

<u>Answer:</u>

<u>For a:</u> The density of the sample of copper is $8.96g/cm^3$

<u>For b:</u> The volume of ethanol needed is 19.0 mL

<u>For c:</u> The mass of mercury is 340. grams

<u>Explanation:</u>

To calculate density of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$ ......(1)

<u>For a:</u>

Mass of copper = 374.5 g

Volume of copper = $41.8cm^3$

Putting values in equation 1, we get:

$\text{Density of copper}=\frac{374.5g}{41.8cm^3}\\\\\text{Density of copper}=8.96g/cm^3$

Hence, the density of the sample of copper is $8.96g/cm^3$

<u>For b:</u>

Mass of ethanol = 15.0 g

Density of ethanol = 0.789 g/mL

Putting values in equation 1, we get:

$0.789g/mL=\frac{15.0g}{\text{Volume of ethanol}}\\\\\text{Volume of ethanol}=\frac{15.0g}{0.789g/mL}=19.0mL$

Hence, the volume of ethanol needed is 19.0 mL

<u>For c:</u>

Volume of mercury = 25.0 mL

Density of mercury = 13.6 g/mL

Putting values in equation 1, we get:

$13.6g/mL=\frac{\text{Mass of mercury}}{25.0mL}\\\\\text{Mass of mercury}=(13.6g/mL\times 25.0mL)=340.g$

Hence, the mass of mercury is 340. grams

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3 years ago

I JUST NEED A REAL ANSWER PLEASE.

ElenaW [278]

Explanation:

hope the picture above help u understand:)

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nika2105 [10]

The transfer of energy that occurs when a force is applied over a distance is WORK.

Hope this helps!

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This is a chemical reaction because a precipitate (solid) was formed from 2 liquids, and there was a color change as well

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