Answer:
88.46%
Explanation:
Percentage yield is actual/theoretical * 100
138/156 * 100 = 88.4615385
Answer:
70 mL of 5% HCl and 30 mL of 15% HCl
Explanation:
We will designate x to be the fraction of the final solution that is composed of 5% HCl, and y to be the fraction of the final solution that is composed of 15% HCl. Since the percentage of the final solution is 8%, we can write the following expression:
5x + 15y = 8
Since x and y are fractions of a total, they must equal one:
x + y = 1
This is a system of two equations with two unknowns. We will proceed to solve for x. First, an expression for y is found:
y = 1 - x
This expression is substituted into the first equation and we solve for x.
5x + 15(1 - x) = 8
5x+ 15 - 15x = 8
-10x = -7
x = 7/10 = 0.7
We then calculate the value of y:
y = 1 - x = 1 - 0.7 = 0.3
Thus 0.7 of the 100 mL will be the 5% HCl solution, so the volume of 5% HCl we need is:
(100 mL)(0.7) = 70 mL
Similarly, the volume of 15% HCl we need is:
(100 mL)(0.3) = 30 mL
Answer: caused by organismis
Explanation:
Answer: M = 2.08 M
Explanation: Molarity is expressed as the number of moles per unit volume in liters. First convert the mass of HCl to moles using its molar mass. Then substitute the variables to the formula for molarity.
75.00 g HCl x 1 mole HCl / 36 g HCl
= 2.08 moles HCl
For Molarity.
M = n / L
= 2.08 moles HCl / 1.000 L
= 2.08 M
1) The answer is: 2 moles of oxygen molecules.
Balanced chemical reaction of methane combustion:
CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g).
Coefficients with the lowest ratio indicate the relative amounts of substances in a reaction.
In fronf of oxygen molecule is coefficient 2.
2) The answer is: 4 moles of oxygen atoms.
In one molecule of oxygen there are two oxygen atoms, so in two molecules there are four oxygen atoms.
