Answer:
Static electricity is the result of an imbalance between negative and positive charges in an object. ... When two materials are in contact, electrons may move from one material to the other, which leaves an excess of positive charge on one material, and an equal negative charge on the other.
D= M/V so, D=300/40 wich is 7.5 so D= 7.5g/m3
Answer:
6.56×10¹⁴ Hz
Explanation:
From the question given above, the following data were obtained:
Wavelength = 457 nm
Frequency =?
Next, we shall convert 457 nm to metre (m). This can be obtained as follow:
1 nm = 1×10¯⁹ m
Therefore,
457 nm = 457 nm × 1×10¯⁹ m / 1 nm
457 nm = 4.57×10¯⁷ m
Thus, 457 nm is equivalent to 4.57×10¯⁷ m
Finally, we shall determine the frequency of the blue light as follow:
Wavelength = 4.57×10¯⁷ m
Velocity of light = 3×10⁸ m/s
Frequency =?
Velocity = wavelength x frequency
3×10⁸ = 4.57×10¯⁷ × frequency
Divide both side by 4.57×10¯⁷
frequency = 3×10⁸ / 4.57×10¯⁷
frequency = 6.56×10¹⁴ Hz
Therefore, the frequency of the blue light is 6.56×10¹⁴ Hz
A) Metal has luster
Metals are ductile, malleable, and good conductors of heat.
Answer:
ΔH°rxn = - 433.1 KJ/mol
Explanation:
- CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
⇒ ΔH°rxn = 4ΔH°HCl(g) + ΔH°CCl4(g) - 4ΔH°Cl2(g) - ΔH°CH4(g)
∴ ΔH°Cl2(g) = 0 KJ/mol.....pure element in its reference state
∴ ΔH°CCl4(g) = - 138.7 KJ/mol
∴ ΔH°HCl(g) = - 92.3 KJ/mol
∴ ΔH°CH4(g) = - 74.8 KJ/mol
⇒ ΔH°rxn = 4(- 92.3 KJ/mol) + (- 138.7 KJ/mol) - 4(0 KJ/mol) - (- 74.8 KJ/mol)
⇒ ΔH°rxn = - 369.2 KJ/mol - 138.7 KJ/mol - 0 KJ/mol + 74.8 KJ/mol
⇒ ΔH°rxn = - 433.1 KJ/mol
