Answer:
copper wire, metal nail, battery
Explanation:
To create an electromagnet, the material to be magnetized (such as a metal nail) is placed inside a solenoid, the ends of the coils are connected to a circuit that includes a battery.
Current is allowed to flow for a few seconds and then cut off. The polarity of the magnet depends on the direction of flow of current in the solenoid.
<span>A)How many moles of O2 are required for the complete combustion of 2.2 g of C3H8 to form CO2 and H2O?
C3H8 + 5O2 = 3CO2 + 4H2O
2.2 g C3H8 ( 1 mol / 44.11 mol ) ( 5 mol O2 / 1 mol C3H8) = 0.25 mol O2
b)A 65.25 g sample of CuSO4•5H2O (M = 249.7) is dissolved in enough water to make 0.800 L of solution. What volume of this solution must be diluted with water to make 1.00 L of 0.100 M CuSO4?
M1V1 = M2V2
[65.25 ( 1 / 249.7 )/ 0.800 L] (V1)= 0.100 (1.00 L)
V1 = 0.31 L or 310 mL </span>
Answer:
2py and 2pz orbitals
Explanation:
Each carbon atom still has two half-filled 2py and 2pz orbitals, which are perpendicular both to each other and to the line formed by the sigma bonds. These two perpendicular pairs of p orbitals form two pi bonds between the carbons, resulting in a triple bond overall (one sigma bond plus two pi bonds).
Answer:
d. Copper (II) sulfate
Explanation:
Given data:
Mass of Al = 1.25 g
Mass of CuSO₄ = 3.28 g
What is limiting reactant = ?
Solution:
Chemical equation:
2Al + 3CuSO₄ → Al₂ (SO₄)₃ + 3Cu
Number of moles of Al:
Number of moles = mass/molar mass
Number of moles = 1.25 g/ 27 g/mol
Number of moles = 0.05 mol
Number of moles of CuSO₄:
Number of moles = mass/molar mass
Number of moles = 3.28 g/ 159.6 g/mol
Number of moles = 0.02 mol
now we will compare the moles of reactant with product.
Al : Al₂ (SO₄)₃
2 : 1
0.05 : 1/2×0.05=0.025 mol
Al : Cu
2 : 3
0.05 : 3/2×0.05 = 0.075 mol
CuSO₄ : Al₂ (SO₄)₃
3 : 1
0.02 : 1/3×0.02=0.007 mol
CuSO₄ : Cu
3 : 3
0.02 : 0.02
Less number of moles of reactants are produced by CuSO₄ thus it will act as limiting reactant.
According to this formula when:
ΔG = ΔH - TΔS = 0
∴ ΔS = ΔH/T
∴ ΔS = n*ΔHVap / Tvap
- when n is the number of moles = mass/molar mass
when the mass = 24.1 g
and the molar mass = 187.3764 g/mol
by substitution:
∴ n = 24.1 / 187.3764g/mol
= 0.129 moles
and ΔHvap is the molar enthalpy of vaporization is 27.49 kJ/mol
and Tvap is the temperature in Kelvin = 47.6 + 273 = 320.6 K
So by substitution, we will get the ΔS the change in entropy:
∴ΔS = 0.129 mol * 27490 J/mol / 320.6 K
= 11 J/K
