The complete answer contains the answer choices.
This is the complete question:
Atoms of which element react spontaneously with Mg2+(aq)? (1)chromium
(2)barium
(3)iron
(4)zinc
Answer: option 2. barium.
Explanation.
1) Mg ²⁺ (aq) is the aquous cation of the metal Mg.
2) Only a metal more reactive than Mg will be able to exchange with it the oxidation states.
3) Mg is an earth alkalyne metal (group 2 of the periodic table). The metals from this group are more reactive than the metals in the groups to its right: 3, 4, 5, 6, 7, ... Only the alkalyne metals (those in group 1) are more reactive than the earth alkalyne metals.
4) Of the list, barium is the only alkalyne metal, so it is more reactive than Mg and will be able to deliver 2 electrons to transform the cations Mg²⁺ into Mg while the very Ba will become Ba²⁺.
5) Chromium, iron and zinc are transition metals, so less metallic (reactive) than Mg.
Answer: The correct option is 2.
Explanation: Heat flow is defined as the transfer of energy from hotter object to cooler object when two objects are kept together at different temperatures. As the energy remains conserved, so the heat flow will take place until the equilibrium is attained.
In the above asked question, Object A is at 40° C and Object B is at 80° C.
Object B is at higher temperature, so the heat flow will take place from Object B to Object A.
Hence, the correct option is 2.
Answer:
A - Liquid molecules forming a gas and gas molecules forming a
liquid are equal in number.
Explanation:
A P E X
