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professor190 [17]

3 years ago

7

Can anyone do these? I have 20 points for who ever can get them. I've completed everything else and these ones are what I'm stuc

k on. Please and thanks.

1 answer:

8_murik_8 [283]3 years ago

8 0

It would be something nvm forgot it

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Which physical method can be used for obtaining a sample of salt from a sm

lana [24]

The physical method that can be used for obtaining a sample of salt from a small beaker of salt and water would be evaporation.

<h3>Separation of salt and water</h3>

A mixture of salt and water can be separated by a method known as evaporation. This is based on the assumption that the salt in question is a water-soluble salt.

In order to separate the salt/water mixture:

Place the mixture in a suitable evaporating dish
Boil the mixture until all the water evaporates.
The remaining residue would be the salt

Care should be taken not to overheat the residue in order to avoid melting. Evaporation is generally used to separate a mixture of water and soluble salt. If the salt is insoluble, filtration using a suitable filter paper will filter off the salt while the water is collected as the filtrate.

More on evaporation can be found here: brainly.com/question/1097783

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Which physical method can be used for obtaining a sample of salt from a small beaker of salt water?

6 0

1 year ago

Which is an example of how people use nonrenewable energy resources?

Arturiano [62]

Answer:

i dont think its walking to school because that doesn't use any resources.

Explanation:

i think its driving a car because we use gasoline for that and for sailing we use the wind. hopefully that helps.

7 0

3 years ago

QUICK! Which best explains how the collisions of materials in space contribute to the formation of layers in protoplanets?

Pani-rosa [81]

Answer:

B. The collisions release heat, which results in the heating and subsequent melting, sinking, and rising of materials.

Explanation:

Got it correct on edge

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3 years ago

What sort of evidence would support at least one of the components of the

Yuki888 [10]

Answer:

(not sure) The origin of all cells observed can be traced to previous cells

Explanation:

- not all cells convert energy (?) (this I'm not sure but think so? might be wrong tho)

- not all cells have cell walls e.g. animal cells only have the cell membrane, no cell wall

- Rocks and other nonliving things are composed of cells: non living things are composed of the elements and not cells (unless they were previously alive, then they contain dead cells)

8 0

3 years ago

A helium-filled balloon at 310.0 K and 1 atm, contains 0.05 g He, and has a volume of 1.21 L. It is placed in a freezer (T = 235

trapecia [35]

Answer : The value of $\Delta E$ of the gas is 2.79 Joules.

Explanation :

First we have to calculate the moles of helium.

$\text{Moles of helium}=\frac{\text{Mass of helium}}{\text{Molar mass of helium}}$

Molar mass of helium = 4 g/mole

$\text{Moles of helium}=\frac{0.05g}{4g/mole}=0.0125mole$

Now we have to calculate the heat.

Formula used :

$q=nc_p\Delta T\\\\q=nc_p(T_2-T_1)$

where,

q = heat

n = number of moles of helium gas = 0.0125 mole

$c_p$ = specific heat of helium = 20.8 J/mol.K

$T_1$ = initial temperature = 310.0 K

$T_2$ = final temperature = 235.0 K

Now put all the given values in the above formula, we get:

$q=nc_p(T_2-T_1)$

$q=(0.0125mole)\times (20.8J/mol.K)\times (235.0-310.0)K$

$q=-19.5J$

Now we have top calculate the work done.

Formula used :

$w=-p\Delta V\\\\w=-p(V_2-V_1)$

where,

w = work done

p = pressure of the gas = 1 atm

$V_1$ = initial volume = 1.21 L

$V_2$ = final volume = 0.99 L

Now put all the given values in the above formula, we get:

$w=-p(V_2-V_1)$

$w=-(1atm)\times (0.99-1.21)L$

$w=0.22L.artm=0.22\times 101.3J=22.29J$

conversion used : (1 L.atm = 101.3 J)

Now we have to calculate the value of $\Delta E$ of the gas.

$\Delta E=q+w$

$\Delta E=(-19.5J)+22.29J$

$\Delta E=2.79J$

Therefore, the value of $\Delta E$ of the gas is 2.79 Joules.

3 0

3 years ago