Answer:
its letter b
Explanation:
it represents the spectrum of stars
Answer:
0.0125 moles of NaOH are present
Explanation:
Molarity, M, is an unit of concentration widely used in chemistry. Is defined as the ratio between moles of solute (In this case, NaOH) and liters of solution.
250.0mL are = 0.250L of solution. As the molarity of the solution is 0.05M = 0.05moles / 1L, the moles present are:
0.250L * (0.05moles / 1L) =
<h3>0.0125 moles of NaOH are present</h3>
Answer:
<h2>mass = 19.98 g</h2>
Explanation:
To find the mass of 1.11 mol of H2O we must first find it's molecular mass after that we use the formula
<h3>m = M × n</h3>
where
m is the mass
M is the molecular mass
n is the number of moles
From the question
n = 1.11 mol
Taking
M( H) = 1 g/mol , M(O) = 16 g/mol
We have
M( H2O) = 2 + 16 = 18 g/mol
So we have
m = 1.11 × 18
We have the final answer as
<h3>mass = 19.98 g</h3>
Hope this helps you
Answer:
A 0.001 molar solution of weak acid has a pH = 4.0,The pKa is :
B. 5
Explanation:
pH = It is negative logarithm of hydrogen ion concentration.
pH = -log([H+])
Ka = It is the dissociation constant.
pKa = -log(Ka)
<u>The acid dissociates according to the equation given below:</u>
Here , The concentration of A- and H+ will be same
So,
[H+] = [A-].....(1)
Now ,
pH = 4.0
pH = -log([H+])
4.0 = -log([H+])
- 4.0 = log([H+]) take antilog both side::"use scientific calculator"
From equation (1), [A-] =
[HA] = 0.001 M (given)
Insert the value of HA , H+ and A- in Ka
pKa = -log(Ka)
pKa = 5
Answer:
2.8 × 10² g
Explanation:
Given data
Step 1: Convert 25°C to the absolute scale
When working with gases, we have to convert the temperatures to the Kelvin scale, using the following expression.
K = °C + 273.15 = 25°C + 273.15 = 298 K
Step 2: Calculate the moles of chlorine gas
We will use the ideal gas equation.
Step 3: Calculate the mass of chlorine gas
The molar mass of Cl₂ is 70.91 g/mol. Then,