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3 years ago

a sample of helium occupies a volume of 101.2 mL at a pressure of 790 mmHg. at what pressure would the volume be 120 mL?

Chemistry

1 answer:

AveGali [126]3 years ago

6 0

Answer : The final pressure will be, 666.2 mmHg

Explanation :

Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

$P\propto \frac{1}{V}$

or,

$P_1V_1=P_2V_2$

where,

$P_1$ = initial pressure = 790 mmHg

$P_2$ = final pressure = ?

$V_1$ = initial volume = 101.2 mL

$V_2$ = final volume = 120 mL

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

$790mmHg\times 101.2mL=P_2\times 120mL$

$P_2=666.2mmHg$

Therefore, the final pressure will be, 666.2 mmHg

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Limiting reactants would appreciate the help

Vanyuwa [196]

Answer:

Explanation:

The Limiting Reactant is that reactant which when consumed in a reaction stops the reaction. The other reactants will be in excess and typically considered non-reactive.

To identify the limiting reactant ...

- write and balance the reaction of interest. Express it in standard form. That is, standard form of a reaction is when the coefficients of the balanced equation are in their lowest whole number values. Also, remember that the standard equation is 'assumed' to be at STP conditions (0°C & 1atm).

- convert all given reactant values to moles

- divide each reactant mole value by the related coefficient of the the balanced standard equation. The smaller value is the limiting reactant. The remaining reactants will be in excess.

Your Problem:

Given: 3Ba + N₂ => Ba₃N₂

22.6g 4.2g ?

moles Ba => 22.6g/137.34g/mol = 0.165 mole Ba

moles N₂ => 4.2g/14.007g/mol= 0.150 mole N₂

Part A: Determining the Limited Reactant

Divide each mole value by respective coefficient ... smallest value is Limiting Reactant.

Barium => 0.165/3 = 0.055 <=> (Limiting Reactant)

Nitrogen => 0.15/1 = 0.15

Barium is the smaller result and is therefore the limiting reactant. This works for ALL limiting reactant type problems. However, be sure to use the mole values calculated first (Ba = 0.165mol & N₂ = 0.150mol) when doing ratio calculations.

Part B: Max (theoretical) amount of Ba₃N₂ produced:

<em>Note: The product yield amounts are based upon the given 'moles' of limiting reactant, NOT the results of the 'divide by respective coefficient' step used to ID the limiting reactant. </em>

3Ba + N₂ => Ba₃N₂ (3:1 rxn ratio for Ba:Ba₃N₂)

moles 0.165mole 0.150mole 1/3(0.165)mole = 0.055mole Ba₃N₂

= 0.055mol(440g/mol) Ba₃N₂

= 24.2 grams Ba₃N₂ (as based

upon Barium as Limiting Reactant)

Part C: Excess N₂ remaining after reaction stops:

From balanced standard reaction, the reaction ratio for Ba:N₂ is 3moles:1mole. That is, for the moles of Ba consumed, 1/3(moles of Ba) = moles of N₂ used.

moles of N₂ used = 1/3(0.165)mole = 0.055mole N₂ used

∴ the amount of N₂ remaining in excess = 0.150mole (given) - 0.055mole (used) = 0.095mole N₂ remaining in excess.

mass N₂ remaining = 0.095mole x 28g/mole = 2.66 grams N₂ remaining in excess.

5 0

3 years ago

If 2 molecules of one reactant combine with 3 molecules of another to produce 5 molecules of a product, then what is the represe

zhenek [66]

Answer:- $2A+3B\rightarrow 5C$

Explanations:- Let's say the first molecule is A and the second molecule is B and the product molecule is C.

From given information, 2 molecules of A react with 3 molecules of B to produce 5 molecules of C.

We write the reactants on left side and the product on right side and there is an arrow between them from reactants towards the products.

So, the reaction could be represented as:

$2A+3B\rightarrow 5C$

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3 years ago

If the enthalpy value for a reaction is negative, what does that indicate about the reaction?

likoan [24]

This indicates that the reaction is exothermic meaning that it releases heat/energy

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3 years ago

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Why are gold rings not made from 100% gold?

aleksandr82 [10.1K]

Gold is actually very soft. If rings were made of pure gold they would bend and become disfigured. Other elements are added to give the ring its stability.

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3 years ago

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a chemical reaction produced 2.50 moles of nitrogen gas. what volume in liters, does this gas sample occupy at STP? (show your w

Harrizon [31]

The volume of N₂ at STP=56 L

<h3>Further explanation</h3>

Given

2.5 moles of N₂

Required

The volume of the gas

Solution

Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, the volume per mole of gas or the molar volume-Vm is 22.4 liters/mol.

So for 2.5 moles gas :

$\tt 2.5\times 22.4=56~L$

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