Answer:
H₂ + O₂ → H₂O
Now, check that oxygen has two atoms on the left and one on the right
so, you put 2 on the right side
H₂ + O₂ → 2H₂O
oxygen is balanced so, add 2 on H₂ to balance out hydrogen
THE FINAL BALANCED EQUATION:
<h2>
2H₂ + O₂ → 2H₂O</h2>
Answer:
Sodium chloride solution:
First you need to calculate the mass of salt needed (done in the explanation), which is 58.44g. Then it have to be weighted in an analytical balance in a weighting boat and then transferred into a 2L volumetric flask that is going to be filled until the mark with distilled water.
Sulfuric acid dilution:
First you need to calculate the volume needed (done in the explanation), it is 16.6 mL. Using a graduated pipette one measures this volume and transfer it into a 2L volumetric flask that is already half filled with distilled water, and then one fills it until its mark.
Explanation:
Sodium chloride solution:
Each liter of a 0.500M solution has half mol, so 2L of said solution has 1 mol of salt. Sodium chloride molar mass is 58.44g/mol, so in 2L of solution there is 58.44g of salt. That`s the mass that`s going to be weighted and transferred to a 2L volumetric flask.
Sulfuric acid dilution:
This is the equation for dilution of solutions:
Where "c1" stands for the initial concentration (stock solution concentration), "v1" for the initial volume (volume of stock solution used), "c2" for the desired concentration and "v2" for the desired volume.
When we are diluting from a stock solution we want to know how much do we have to pipette from the stock solution into our volumetric flask. We do so by isolating the "v1" term from the dilution equation:
in this case that would be:
First we will calculate the number of moles of Iron:

, where n is the number of moles, m is the mass of iron in the reaction and M is the Atomic weight.

moles of Iron.
The same number of moles of Oxygen will take part in the reaction.
So

where 32 is the Atomical Weight of Oxygen (16 x 2).
=>

g
Answer:
6.0 x 10 to the power of 23
Answer:
D. 6.3 x 10-5 mol/L NaOH
Explanation:
Alizarin yellow is an indicator that is yellow when pH < 10.1. In the same way, thymol blue is blue when pH > 9
That means the pH of the solution is between 9 - 10.1
Any acid as HCl could have a pH of these.
The solution of 3.2x10⁻⁴M NaOH has a pH of:
pOH = -log[OH-] = 3.49
pH = 14-pOH = 10.51. The pH of the solution is not 10.5
Now, the solution of 6.3x10⁻⁵M NaOH has a pH:
pOH = -log[OH-] = 4.2
pH = 14-pOH = 9.8
The pH of the solution could be 9.8. Right option is:
<h3>D. 6.3 x 10-5 mol/L NaOH</h3>