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3 years ago

What is the physical state of helium at room temperature

1 answer:

3 0

Depending on the exact room temp, say the helium is in a plastic (one of the ones you buy already full of helium) balloon. Now, you should notice the balloon may be a little squishy, but it is still afloat and looking happy. If you took it outside on a cold day, it would deflate, but when you take it back inside where it is warm, it will reinflate. This is called Boyle's Law. Think if it as if the Helium molecules are partying in the balloon, but when they go out in the cold, they huddle together for warmth.

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An ideal gaseous reaction (which is a hypothetical gaseous reaction that conforms to the laws governing gas behavior) occurs at

pochemuha

Total internal energy change is equals to -44.83kJ

Q=-73.2kJ (negative sign indicates that heat was released by the system),

P= 50.0atm

ΔU= Q + W, FIRST LAW OF THERMODYNAMICS..........(1)

ΔV= Final volume - initial volume= 2.00 litre - 7.60litre= -5.60litre

work done by the system (w)= -PΔV

w= -(50.0×(-5.60)) atm×litre= 280atm litre

1 atm litre= 101.325J

w= 280 ×101.325 J= 28,371J

1kJ=1000J,

w=28.37KJ,

so putting in the values in equation (1)...

energy change(ΔU) = -73.2 kJ + 28.37 kJ

= - 44.83 kJ

7 0

3 years ago

water from a town is suspected to contain chloride ions but not sulphate ions . describe how the presence of the chloride ions i

andreyandreev [35.5K]

Answer:

See Explanation

Explanation:

The presence of chloride ions in water can be established by adding dilute trioxonitrate V acid to a sample of the water in drops followed by aqueous silver trioxonitrate V.

If a white precipitate is formed, which is soluble in excess aqueous ammonia solution, then the presence of chloride ion in the water sample is ultimately confirmed.

3 0

2 years ago

(b) What property do all elements in the same column of the Periodic Table as

Shalnov [3]

Well the group fluorine is in is known as Halogens. Halogens all have seven valence electrons in their outer shell. They exist as diatomic molecules. Furthermore they readily combine with metals to form salts

7 0

3 years ago

Read 2 more answers

Water boils at rate of ........and freeze at ........

Schach [20]

100 degree celcius and 0 degree Celsius

7 0

3 years ago

How many moles of hydrogen are in the sample? Round your answer to 4 significant digits.

finlep [7]

Answer:

1.56 mol H₂

Explanation:

Mg₃(Si₂O₅)₂(OH)₂

There are 4 Si moles per Mg₃(Si₂O₅)₂(OH)₂ mol. With that in mind we can calculate how many Mg₃(Si₂O₅)₂(OH)₂ moles are there in the sample, using the given number of silicon moles:

3.120 mol Si * $\frac{1molMg_3(Si_2O_5)_2(OH)_2}{4molSi}$ = 0.78 mol Mg₃(Si₂O₅)₂(OH)₂

Then we can convert Mg₃(Si₂O₅)₂(OH)₂ moles into hydrogen moles, keeping in mind that there are 2 hydrogen moles per Mg₃(Si₂O₅)₂(OH)₂ mol:

0.78 mol Mg₃(Si₂O₅)₂(OH)₂ * 2 = 1.56 mol H₂

8 0

3 years ago