Answer:
12.99
Explanation:
<em>A chemist dissolves 716. mg of pure potassium hydroxide in enough water to make up 130. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Be sure your answer has the correct number of significant digits.</em>
Step 1: Given data
- Mass of KOH: 716. mg (0.716 g)
- Volume of the solution: 130. mL (0.130 L)
Step 2: Calculate the moles corresponding to 0.716 g of KOH
The molar mass of KOH is 56.11 g/mol.
0.716 g × 1 mol/56.11 g = 0.0128 mol
Step 3: Calculate the molar concentration of KOH
[KOH] = 0.0128 mol/0.130 L = 0.0985 M
Step 4: Write the ionization reaction of KOH
KOH(aq) ⇒ K⁺(aq) + OH⁻(aq)
The molar ratio of KOH to OH⁻is 1:1. Then, [OH⁻] = 0.0985 M
Step 5: Calculate the pOH
We will use the following expression.
pOH = -log [OH⁻] = -log 0.0985 = 1.01
Step 6: Calculate the pH
We will use the following expression.
pH + pOH = 14
pH = 14 - pOH = 14 -1.01 = 12.99
Answer:
186.9Kelvin
Explanation:
The ideal gas law equation is PV
=
n
R
T
where
P is the pressure of the gas
V is the volume it occupies
n is the number of moles of gas present in the sample
R is the universal gas constant, equal to 0.0821
atm L
/mol K
T is the absolute temperature of the gas
Ensure units of the volume, pressure, and temperature of the gas correspond to R
( the universal gas constant, equal to 0.0821
atm L
/mol K
)
n
=
3.54moles
P= 1.57
V= 34.6
T=?
PV
=
n
R
T
PV/nR = T
1.57 x 34.6/3.54 x 0.0821
54.322/0.290634= 186.908620464= T
186.9Kelvin ( approximately to 1 decimal place)
The moon orbiting around the earth.
A: the ball in frame A had the highest velocity, and the ball in frame B has the highest kinetic energy
Mass to moles
5.2 mol/Ca(no3)2 to mol
5.2 mol/Ca(no3)2 / molar mass
5.2 mol/Ca(no3)2 / 164.1= 0.032 g/Ca(no3)2