Answer:
The concentration of the solution is 2.86 M
Explanation:
Molarity is a unit of concentration based on the volume of a solution. It is defined as the number of moles of solute that are dissolved in a given volume. In other words, molarity is defined as the number of moles of solute per liter of solution.
The Molarity of a solution is determined by the following expression:
Molarity is expressed in units ().
In this case, you must then know the number of moles of HF, for which you must know the molar mass. Being:
the molar mass of HF is: HF= 1 g/mole + 19 g/mole= 20 g/mole
Then the following rule of three applies: if 20 g of HF are available in 1 mole, 14.3 g in how many moles will they be?
moles= 0.715
So:
- number of moles of solute: 0.715 moles
- Volume: 250 mL=0.250 L (being 1 L=1000 mL)
Replacing:
Solving:
Molarity= 2.86 =2.86 M
<u><em>The concentration of the solution is 2.86 M</em></u>
Water,paper,rice,carbon,dioxide,sand,salt,nitrate,bacteria,hair
Answer:
a. Rate constant: 1.2118x10⁻⁴ yrs⁻¹
b. The age of the object is 20750 years
Explanation:
a. We can solve the rate constant in an isotope decay by using Half-Life, as follows:
K = Ln 2 / Half-life
K = ln 2 / 5720 years =
<h3>1.2118x10⁻⁴ yrs⁻¹</h3><h3 />
b. The general equation of isotope decay is:
Ln [A] = -kt + Ln [A]₀
<em>Where [A] is concentration of the isotope after time t, </em>
<em>k is rate constant</em>
<em>and [A]₀ initial concentration of the isotope.</em>
<em />
Computing the values of the problem:
Ln [0.89x10⁻¹⁴] = -1.2118x10⁻⁴ yrs⁻¹t + Ln [1.1x10⁻¹³]
-2.5144 = -1.2118x10⁻⁴ yrs⁻¹t
20750 years = t
The age of the object is 20750 years
<em />
The bottom answer is the correct one