Full question options;
(Fe, Pb, Mg, or Ca)
Answer:
Iron - Fe
Explanation:
We understand tht metals pretty much form bonds by losing their valence (outermost electrons). But this question specifically asks for metals that lose beyond their outermost electrons; next to outermost principal energy levels.
Pb, Mg, and Ca only lose their outermost electrons to form the following ions;
Pb2+, Mg2+, and Ca2+.
This is because their ions have achieved a stable octet configuration - the dreamland of atoms where they are satisfied and don't need to go into reactions again.
Iron on the other hand has the following electronic configurations;
Fe: [Ar]4s2 3d6
Fe2+: [Ar]4s0 3d6
Fe3+: [Ar]4s0 3d5
This means ion can lose both the ooutermost electrons (4s) and next to outermost principal energy levels (3d). So correct option is Iron.
1) List the reactants: sodium bicarbonate (NaHCO₃) and citric acid (H₃C₆H₅O₇).
Reactants undergo change during a chemical reaction.
2) List the products: water (H₂O), carbon dioxide (CO₂) and sodium citrate (Na₃C₆H₅O₇).
Products are the substances formed from chemical reactions.
3) The balanced chemical equation:
3NaHCO₃ + H₃C₆H₅O₇ → 3H₂O + 3CO₂ + Na₃C₆H₅O₇.
First you need to find the amount of mass of Na2CO3 in one moles
(Use periodic chart)
Na= 22.99 x 2 = 45.98
C = 12.01
O = 16.00 x 4 = 64.00
Add the molar masses together to get 121.99
To find how many grams are in 4 moles, times 121.99 by 4
This gives you 487.96
But the questions asks for the answer to be in kilograms nor grams, to change into kilograms divide by 1000
This gets you the answer: 0.49 kg
Preparing 15 mg/gl working standard solution from a 20 mg/dl stock solution will require the application of the dilution principle.
Recalling the principle:
initial volume x initial molarity = final volume x final molarity
Since we were not given any volume to work with, we can as well just take an arbitrary volume to be prepared. Let's assume that the stock solution is 10 mL and we want to prepare 15 mg/gl from it:
Applying the dilution principle:
10 x 20 = final volume x 15
final volume = 200/15
= 13.33 mL
This means that in order to prepare 13.33 mL, 15 mg/l working standard solution from 10 ml, 20 mg/dl stock solution, 3.33 mL of the diluent must be added to the stock solution.
More on dilution principle can be found here: brainly.com/question/11493179
