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3 years ago

Which best describes a compound?

Chemistry

1 answer:

Volgvan3 years ago

4 0

Answer: A elements that are chemically combined

It´s the right answer i learn it already

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A sample of helium gas occupies 355ml at 23°c. if the container the he is in is expanded to 1.50 l at constant pressure, what is

ss7ja [257]

Answer: The final temperature would be 1250.7 K.

Explanation: We are given a sample of helium gas, the initial conditions are:

$V_{initial}=355mL=0.355L$ (Conversion factor: 1L = 1000 mL)

$T_{initial}=23\°C=296K$ (Conversion Factor: 1° C = 273 K)

The same gas is expanded at constant pressure, so the final conditions are:

$V_{initial}=1.50L$

$T_{initial}=?K$

To calculate the final temperature, we use Charles law, which states that the volume of the gas is directly proportional to the temperature at constant pressure.

$V\propto T$

$\frac{V_{initial}}{T_{initial}}=\frac{V_{final}}{T_{final}}$

Putting the values, in above equation, we get:

$\frac{0.355L}{296K}=\frac{1.50L}{T_{final}}$

$T_f=1250.7K$

5 0

2 years ago

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You have a 5-liter container with 1.30×10^24 molecules of ammonia gas (NH3) at STP.

givi [52]

Answer:answer is C

Explanation:

3 0

2 years ago

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A 80.0 g piece of metal at 88.0°C is placed in 125 g of water at 20.0°C contained in a calorimeter. The metal and water come to

grandymaker [24]

Answer:

The specific heat of the metal is 0.485 J/g°C

Explanation:

<u>Step 1:</u> Data given

Mass of the piece of metal = 80.0 grams

Mass of the water = 125 grams

Initial temperature of the metal = 88.0 °C

Initial temperature of water =20.0 °C

Final temperature = 24.7 °C

pecific heat of water is 4.18 J/g*°C

<u>Step 2:</u> Calculate specific heat of the metal

Qgained = -Qlost

Q =m*c*ΔT

Qwater = - Qmetal

m(water)*c(water)*ΔT(water) = -m(metal)*c(metal)*ΔT(metal)

with mass of water = 125 grams

with c( water) = 4.18 J/g°C

with ΔT(water) = T2-T1 = 24.7 - 20 = 4.7°C

with mass of metal = 80.0 grams

with c(metal) = TO BE DETERMINED

with ΔT(metal) = 24.7 - 88.0 = -63.3 °C

125*4.18*4.7 = -80 * C(metal) * -63.3

2455.75 = -80 * C(metal) * -63.3

C(metal) = 2455.75 / (-80*-63.3)

C(metal) = 0.485 J/g°C

The specific heat of the metal is 0.485 J/g°C

3 0

3 years ago

A solution is made by dissolving

nikklg [1K]

Answer:

THE MOLARITY IS 2.22 MOL/DM3

Explanation:

The solution formed was as a result of dissolving 37.5 g of Na2S in 217 g of water

Relative molecular mass of Na2S = ( 23* 2 + 32) = 78 g/mol

Molarity in g/dm3 is the amount of the substance dissolved in 1000 g or 1 L of the solvent. So we have;

37.5 g of Na2S = 217 g of water

( 37.5 * 1000 / 217 ) g = 1000 g of water

So, 172.81 g/dm3 of the solution

So therefore, molarity in mol/dm3 = mol in g/dm3 / molar mass

Molarity = 172.81 g/dm3 / 78 g/mol

Molarity = 2.22 mol/dm3

The molarity of the solution is 2.22 mol/dm3

4 0

3 years ago

If a chemist has 2.3 moles of arsenic that has a molar mass of 74.92g/mol, which would be the best way to find out how many atom

scZoUnD [109]

Mulitply 2.3 by avogadros #

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3 years ago

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