Answer:
Mass = 18.9 g
Explanation:
Given data:
Mass of Al₂O₃ formed = ?
Mass of Al = 10.0 g
Solution:
Chemical equation:
4Al + 3O₂ → 2Al₂O₃
Number of moles of Al:
Number of moles = mass/molar mass
Number of moles = 10.0 g/ 27 g/mol
Number of moles = 0.37 mol
Now we will compare the moles of Al and Al₂O₃.
Al : Al₂O₃
4 : 2
0.37 : 2/4×0.37 = 0.185 mol
Mass of Al₂O₃:
Mass = number of moles × molar mass
Mass = 0.185 mol × 101.9 g/mol
Mass = 18.9 g
C. All of the missing mass has been converted into heat energy. It doesn’t affect the Law of Conservation of Mass because it uses Einstein’s law E=MC2
Answer:
B. It increases.
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.
It is clear that, at constant P, the volume of the gas (V) is directly proportional to the temperature of the gas.
<em>V ∝ T.</em>
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<em>So, If a balloon is heated, the volume of the air in the balloon if the pressure is constant:</em>
B. It increases.
Density= 5m^3
Explanation:
Here, the Mass of an object is 25g
To convert grams into kilograms, we need to divide 25 by 1000
so, the 25g=25/1000 = 0.025kg.
The volume of an object is given by 5cm^3 ( cubic centimetre)
To convert cubic centimetre to meter cube, we need to divide 5 by 1000.
So, 5cm^3=5/1000=0.005m^3
Finally, the equation of density is
DENSITY= MASS/VOLUME
Density = 0.025/0.005
= 5m^3
Hence, the density of the object is 5m^3.