Im a bit torn here, lets look at the definitions of physical and chemical changes:
physical change changes only the phase/state of a substance, but not what the substance is
chemical change is a chemical reaction where a new substance is formed and energy is given off or absorbed.
(it just started raining and it smells really nice out my window)
clearly, this cannot be just a physical reaction. i think i would be inclined to pick B. but C. could have merit as an answer too. sorry for the ambiguity x
Answer: m = 50 g ZnSO4
Explanation: First is convert the moles of Zn to the moles of ZnSO4 by having their mole ratio which is 2:2 based from the balanced equation. Next is convert the moles of ZnSO4 to mass using its molar mass.
0.311 mole Zn x 2 moles ZnSO4 / 2 moles Zn
= 0.311 moles ZnSO4
0.311 moles ZnSO4 x 161 g ZnSO4 / 1 mole ZnSO4
= 50 ZnSO4
Explanation:
4. limestone heat lime + carbon dioxide
The reactants in this expression above is limestone
The products of the reaction is carbon dioxide and lime
Reactant is the species that gives the product and it is usually found on the left hand side of the expression.
The product is the substance on the right hand side of the expression that forms through the experiment.
Heat is used to facilitate the reaction.
5. An exothermic reaction is a reaction in which heat is given off.
An endothermic reaction is a reaction in which heat is absorbed in the process.
An exothermic reaction is always warmer after the reaction whereas an endothermic reaction is colder at the end of the reaction.
While the number nuclear protons as given is 34, and therefore we deal with the element selenium, there are 2 more electrons than protons, and therefore this species has an overall
2
−
charge.
We represent this selenide ion as
S
e
2
−
. Do I win 5 pounds?
Z= 34, therefore the atom is selenium
