The pairs are:
K, Kr - Same period
Be, Mg - Same group
Ni, Tc - Both are transition metals
B, Ge - Both are metaloids
Al, Pb - Both form inert oxides
Answer:
The unknown metal could be calcium or magnesium.
Explanation:
Displacement of a metal from its chemical reaction is shown by the reaction known as single displacement reaction. The reactivity of metal is determined by the reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the reactivity series.
Metal B is more reactive than metal A.
The metal which easily displaced aluminium will lie above in the series but that same element cannot displace sodium, so it will lie below in the series.
Hence, from the series, we conclude that the unknown metal could be calcium or magnesium.
First one is reactants and then second one is products
Answer:
= - 303.975 Joules
Explanation:
Given that:
The volume of the cylinder = 0.003 m^3
Now, to liters:
The volume = 0.003 *1000 L
= 3 L
For an open cylinder, we mean the atmospheric pressure is at standard condition.
Thus, the workdone = -PΔV
= - 1 atm (3 L)
= - 3 L atm
1 L atm to Joules
= 101.325 Joules
Therefore;
=- 3* 101.325 Joules
= - 303.975 Joules
According to this formula:
pH = - log [H]
And, pOH = - log [OH] >>> (1)
Where, pH + pOH = 14 >>> (2)
∵ the hydroxide ion concentration = (OH-) = 10 ^ -10 M
from (1) and (2) and by substitution:
∴ pOH = - log [10^-10] = 10
∴ pH = 14 - 10 = 4
