Amount of substance can be measured in the number of moles.
Avagadros constant states that 1 mol of any substance is made of 6.022 x 10^23 units.
These units could be atoms making up elements or molecules making up compounds
1 mol of C is made of 6.022 x 10^23 atoms of C
Since 1 mol of C has a mass of 12.011 g
Therefore 6.022 x 10^23 atoms of C weigh 12.011 g
Then 1 atom of C weighs -12.011 g / 6.022 x 10^23 atoms = 1.99 x 10^(-23) g
Mass of 1 C atom is 1.99 x 10^(-23) g
Answer : The heat of the reaction is, 1.27 kJ/mole
Explanation :
First we have to calculate the heat released.
Formula used :
or,
where,
Q = heat = ?
m = mass of sample = 1.50 g
c = specific heat of water = 
= initial temperature = 
= final temperature = 
Now put all the given value in the above formula, we get:
Now we have to calculate the heat of the reaction in kJ/mol.
where,
= enthalpy change = ?
Q = heat released = 0.0238 kJ
n = number of moles NH₄NO₃ = 
Therefore, the heat of the reaction is, 1.27 kJ/mole
Answer:
B. compound
Explanation:
A pure substance can be an element, which consists of only one type of atom and cannot be broken down by a chemical change, or a compound, which consists of two or more types of atoms.
Answer:
4.31 atm.
Explanation:
- We can use the general law of ideal gas: <em>PV = nRT.</em>
where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
- If n and V are constant, and have different values of P and T:
<em>(P₁T₂) = (P₂T₁)</em>
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P₁ = 3.81 atm, T₁ = 25°C + 273 = 298 K,
P₂ = ??? atm, T₂ = 50°C + 273 = 323 K,
- Applying in the above equation
(P₁T₂) = (P₂T₁)
<em>∴ P₂ = (P₁T₂)/(T₁)</em> = (3.81 atm)(323 K)/(298 K) = <em>4.31 atm.</em>
