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3 years ago

Butter melt when you heat it in a pan on the stove. Is this a chemical change or physical change? How can you tell?

1 answer:

4 0

It would be an physical change ; if you melt butter the butter goes from a solid to a liquid so therefore the physical state is changed.

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What do these two changes have in common?

Vladimir79 [104]

They are both physical changes (change in physical structure/appearance)

hope this helps :)

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3 years ago

Does ultraviolet block sunburn

satela [25.4K]

Answer:

Explanation:

8 0

4 years ago

In 2012, the number of people attending the South Coast Comic Convention was 5,000. The number of attendees continues to grow at

Ray Of Light [21]

11000 = 5000(1.087)^t

6 0

3 years ago

Read 2 more answers

Lead metal can be extracted from a mineral called galena, which contains 86.6% lead by mass. a particular ore contains 68.5% gal

rjkz [21]

The volume of sphere can be calculated using the following formula:

$V=\frac{4}{3}\pi r^{3}$

Here, r is radius of the sphere which is 8 cm. Putting the value,

$V=\frac{4}{3}\pi r^{3}=\frac{4}{3}(3.14)(8 cm)^{3}=2143.57 cm^{3}$

This is equal to the volume of lead, density of lead is $11.34 g/cm^{3}$ thus, mass of lead can be calculated as follows:

$m=d\times V=11.34 g/cm^{3}\times 2143.57 cm^{3}=2.43\times 10^{4}g$

Let the mass of ore be 1 g, 68.5% of galena is obtained by mass, thus, mass of galena obtained will be 0.685 g.

Now, 86.6% of lead is obtained from this gram of galena, thus, mass of lead will be:

m=0.685×0.866=0.5932 g

Therefore, 0.5932 g of lead is obtained from 1 g of ore, if the efficiency is 100%.

For 92.5% efficiency, mass of lead obtained will be:

$m=\frac{92.5}{100}\times 0.5932=0.5487 g$

Thus, 1 g of lead obtain from $\frac{1}{0.5487}=1.822$ grams of ore.

Thus, $2.43\times 10^{4} g$ of lead obtain from:

$2.43\times 10^{4}\times 1.822=4.42\times 10^{4}g=44.2 kg$

Therefore, mass of ore required to make lead sphere is 44.2 kg.

4 0

3 years ago

Read 2 more answers

the word property can refer to a characteristic, such as a characteristic of a layer of the suns atmosphere. what is another mea

olganol [36]

Answer:

property can also refer to a belonging or someone's property/items

3 0

3 years ago