Energy released from changing the phase of a substance from the gas phase to liquid phase can be calculated by using the specific latent heat of vaporization. The heat of fusion of water at 0 degrees Celsius is 40.7 kJ/mol. Calculation are as follows:<span> </span>
Energy = 27.9 g (1 mol / 18.02 g) x 40.7 kJ/mol
Energy = 63.09 kJ
The house wiring should be done parallel because, in parallel connection there will be more advantages than a series connection.
Let a house is wired in series and it contains a fan, tube light, TV, refrigerator. All the devices are connected in series. Now, due to some disturbance the fan speed working or it burned. Then since the connection was a series, due to one appliance failure causes the whole circuit to fail. If it is burned that means it making an open circiut. Then there will be no current flow in the circuit.
Now if it was a parallel connection as we know already, the parallel connection is nothing but individual appliances connected to the same line by tappings. That means there's no dependency of one appliance on another. So if an appliance fail or burns it doesn't effects the remaining appliances. And there will be uninterrupted supply to the healthy appliances can be achieved.
That’s why we use parallel for house wiring
Answer: K and Na
Explanation:
Potassium and Sodium have a chemical symbol of K and Na respectively.
They have similar chemical properties because both
- have only one valence electron,
- form univalent positive ion when they donate their lone outermost electron as shown below
Na --> Na+ + e-
K --> K+ + e-
- are good reducing agents
- react with cold water vigorously to liberate hydrogen gas and form alkalis, so they are known as alkali metals.
- K and Na are placed in Group 1 of the periodic table.
Thus, unlike the other pairs given, K and Na, have the most similar chemical properties
Answer:
0.50 moles of Cu
Explanation:
The balanced chemical equation for given synthetic reaction is,
2 Cu + S → Cu₂S
According to balance chemical equation,
1 mole of Cu₂S is produced by = 2 moles of Cu
So,
0.25 moles of Cu₂S will be produced by = X moles of Cu
Solving for X,
X = 0.25 mol × 2 mol / 1 mol
X = 0.50 moles of Cu
Hence, as the molar ratio of Cu to Cu₂S is 2:1 hence, to produce 0.25 moles of Cu₂S we will need 0.50 moles of Cu.
A mixture that results when substances dissolve to form a homogeneous mixture is a solution.
