The correct answer is d) methane (

)
The other options are elements.
Answer: (1)CaSO4 -> (2)O2 + (1)CaS
Explanation: edge 2020 chem
Answers:
(a) 1s² 2s²2p³; (b) 1s² 2s²2p⁶ 3s²3p⁶ 4s²3d²; (c) 1s² 2s²2p⁶ 3s²3p⁵
Step-by-step explanation:
One way to solve this problem is to add electrons to the orbitals one-by-one until you have added the required amount.
Fill the subshells in the order listed in the diagram below. Remember that an s subshell can hold two electrons, while a p subshell can hold six, and a d subshell can hold ten.
(a) <em>Seven electrons
</em>
1s² 2s²2p³
There are two electrons in the 2s subshell and three in the 2p subshell. The remaining two electrons are in the inner 1s subshell.
(b) <em>22 electrons
</em>
1s² 2s²2p⁶ 3s²3p⁶ 4s²3d²
There are two electrons in the 4s subshell and two in the 2p subshell. The remaining 18 electrons are in the inner subshells.
(c) <em>17 electrons</em>
1s² 2s²2p⁶ 3s²3p⁵
There are two electrons in the 3s subshell and five in the 2p subshell. The remaining 10 electrons are in the inner subshells.
Answer: 2NOBr(g) ⇌ 2NO(g) + Br2(g)
Explanation: For volume changes in equillibrium, the following are to be taken into consideration:
- Volume changes have no effect on equillibrium system that contains solid or aqueous solutions.
- An increase in volume of an equilibrium system will shift to favor the direction that produces more moles of gas.
- A decrease in volume of an equilibrium system will shift to favor the direction that produces less moles of gas.
- Volume changes will have no effect on the equillibrium system if there is an equal number of moles on both sides of the reaction.
2NOBr(g) ⇌ 2NO(g) + Br2(g) is the equillibrium system because there are more moles of products,therefore an increase in the volume of the reaction will shift to the right and produce more moles of products. Also both reactants and products exist in the gaseous state and does not have equal number of moles.