Answer:
They decrease, because of the stronger effective nuclear charge.
Explanation:
- Atomic radii decreases from left to right across a period.
- This is due to the increase in the no. of protons and electrons through the period.
- One proton has a greater effect than one electron.
- So, electrons are attracted towards the nucleus and resulting in a smaller atomic radii.
<em>Thus, the right choice is: They decrease, because of the stronger effective nuclear charge.</em>
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Answer:
The system gains 126100 J
Explanation:
The heat can be calculated by the equation:
Q = nxCxΔT, where Q is the heat, C is the heat capacity,n is the number of moles and ΔT is the variation of temperature (final - initial). The number of moles is the mass divided by the molar mass, so:
n = 250/4 = 62.5 mol.
The system must be in thermal equilibrium with the surroundings, so if the temperature of the surroundings decreased 97 K, the temperature of the system increased by 97 K, so ΔT = 97 K
Q = 62.5x20.8x97
Q = 126100 J
Answer:
The average rate is 2.84 X 10⁻³ Ms⁻¹
Explanation:
Average rate = -0.5*Δ[HBr]/Δt
given;
[HBr]₁ = 0.590 M
[HBr]₂ = 0.465 M
Δ[HBr] = [HBr]₂ - [HBr]₁ = 0.465 M - 0.590 M = -0.125 M
Δt Change in time = 22.0 s
Average rate = -0.5*Δ[HBr]/Δt
Average rate = - 0.5(-0.125)/22
Average rate = 0.00284 Ms⁻¹ = 2.84 X 10⁻³ Ms⁻¹
Therefore, the average rate is 2.84 X 10⁻³ Ms⁻¹
Answer is A. Because K is potassium which is a metal
