Answer:
9.45 × 10⁻³ M
Explanation:
Step 1: Given data
- Mass of calcium nitrate (solute): 155 mg (0.155 g)
- Volume of solution: 100. mL (0.100 L)
Step 2: Calculate the moles of solute
The molar mass of Ca(NO₃)₂ is 164.09 g/mol.
0.155 g × 1 mol/164.09 g = 9.45 × 10⁻⁴ mol
Step 3: Calculate the molarity of the solution
The molarity is equal to the moles of solute divided by the liters of solution.
M = 9.45 × 10⁻⁴ mol/0.100 L = 9.45 × 10⁻³ M
The answer is b. i believe
hope this helps!
Answer:
6.73g
Explanation:
T½ = 5.2days
No = 80g
N = ?
T = 20.8days
We'll have to find the disintegration constant first so that we can plug it into the equation that will help us find the mass of the sample after 20.8 days
T½ = In2 / λ
T½ = half life
λ = disintegration constant
λ = In2 / T½
λ = 0.693 / 5.8
λ = 0.119
In(N / No) = -λt
N = final mass of the radioactive sample
No = initial mass of the sample
λ = disintegration constant
t = time for the radioactive decay
In(N/No) = -λt
N / No = e^-λt
N = No(e^-λt)
N = 80 × e^-(0.119 × 20.8)
N = 80 × e^-2.4752
N = 80 × 0.0841
N = 6.728g
The mass of the sample after 20.8 days is approximately 6.73g
2H2+O2=2H2O
This is the chemical formula for water. Hope this helps.