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4 years ago

Does anyone understand this?

Chemistry

1 answer:

Nikolay [14]4 years ago

7 0

From start:

Joule, J, calorie,

Example 1: 120 J / 4.184 = 28.68 cal
Example 2: 1200 cal * 4.184 = 5020.8 J

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A movable piston traps 0.205 moles of an ideal gas in a vertical cylinder. If the piston slides without friction in the cylinder

Mazyrski [523]

Answer : The work done on the gas will be, 418.4 J

Explanation :

First we have to calculate the volume at 270°C.

$PV_1=nRT$

where,

P = pressure of gas = 1 atm

$V_1$ = volume of gas = ?

T = temperature of gas = $270^oC=273+270=543K$

n = number of moles of gas = 0.205 mol

R = gas constant = 0.0821 L.atm/mol.K

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

$(1atm)\times V_1=0.205mol\times 0.0821L.atm/mol.K\times 543K$

$V_1=9.12L$

Now we have to calculate the volume at 24°C.

$PV_2=nRT$

where,

P = pressure of gas = 1 atm

$V_2$ = volume of gas = ?

T = temperature of gas = $24^oC=273+24=297K$

n = number of moles of gas = 0.205 mol

R = gas constant = 0.0821 L.atm/mol.K

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

$(1atm)\times V_2=0.205mol\times 0.0821L.atm/mol.K\times 297K$

$V_2=4.99L$

Now we have to 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 = 9.12 L

$V_2$ = final volume = 4.99 L

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

$w=-p(V_2-V_1)$

$w=-(1atm)\times (4.99-9.12)L$

$w=4.13L.artm=4.13\times 101.3J=418.4J$

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

Therefore, the work done on the gas will be, 418.4 J

6 0

3 years ago

What is the source of carbon 14 in our environment ?

maksim [4K]

The reaction of atomic N with neutrons in the upper atmosphere

6 0

3 years ago

How many moles are in 89 grams of KCI

Pani-rosa [81]

Answer:

The number of moles in 89 grams of KCl is approximately 1.193 moles

Explanation:

A mole of an element or compound, is the quantity of the element or compound that contains 6.022 × 10²³ molecules of the element or compound, such that the molar mass of one mole is dependent on the mass of each molecule of the element or compound that make up the 6.022 × 10²³ particles

The given parameters are;

The mass of the KCl = 89 grams

The Molar mass, MW, of potassium, K = 39.1 g/mole

The Molar mass, MW, of chlorine, Cl = 35.5 g/mole

Therefore, given that KCl, has one K and one Cl, per mole, we have;

The Molar mass, MW, of potassium chloride, KCl = (39.1 + 35.5) g/mole = 74.6 g/mole

$The \ number \ of \ moles, n=\dfrac{Mass}{Molar \ mass, MW}$