193.38 K was the initial temperature of the krypton.
Initial volume of the krypton gas = 6 litres
initial pressure of the krypton gas = 0.960 atm
initial temperature of the krypton gas = ?
final volume of the krypton gas = 7.70 litres
final pressure of the Krypton gas = 1.25 atm
final temperature of the krypton gas = 55 degrees or 273.25+55 = 323.15 K
Applying the Combined Gas Laws:
Rearranging the equation:
Putting the value in the equation:
T1 = 193.38 K
Initial temperature of the krypton gas is 193.78 K
The equation of the reaction is;
2 Al(s) + Fe2O3(aq) ------> Al2O3(aq) + 2Fe(s)
Number of moles in 20g of Al= 20g/27 g/mol = 0.74 moles
From the reaction equation;
2 moles of Al yields 2 moles of Fe
0.74 moles of Al yields 0.74 moles of Fe
Mass of Fe produced = 0.74 moles of Fe * 56 g/mol
Mass of Fe produced = 41.44 g of Fe (This is the theoretical yield of Fe)
percent yield = actual yield/ theoretical yield * 100
actual yield = 32.67 grams of iron
percent yield = 32.67 g/41.44 g * 100
percent yield = 78.8%
Answer: 6 valence electrons
Explanation: the valence electrons and group are always the same, but when the group numbers are 10 and above, they would be the first number. For example, every element in group 16 has 6 valence electrons.
d. oxygen (O2) is the answer
d- 334 kJ/g.
You can detect it from the units of the different choices.
a- has the unit J/g.°C that is the unit of the specific heat capacity (c).
b- has the unit Kelvin that is the unit of temperature.
c- has the unit g/mol which is the unit of the molar mass.
d- has the unit kJ/g which is the unit of the enthalpy divided by the no. of rams that is the specific entha;py of fusion.
<em>So, the right choice is: d- 334 kJ/g.</em>