Answer:
The atomic weight of Rubidium (Rb) is 85.91 amu, using 4 significant figures.
Explanation:
The average atomic mass of Rubidium (Rb) is composed by the mass of the two given isotopes 85^Rb and 87^Rb but each isotope has a different abundance in nature expressed by percentage (natural occurrence).
Therefore, we need to calculate how much of this mass with its abundance percentage contribute to the average atomic mass for each isotope.
First step: Calculate the contribution in mass using the natural occurrence percentage.
85^Rb = 84.91 × 
= 61.73 amu
87^Rb = 86.91 ×
= 24.18 amu
The answers for each isotope are given using a typical percentage formula.
Second step: Add the two mass values founded.
24.18 amu + 61.73 amu = 85.91 amu
Third Step: Check the significant figures
The answer is 85.91 amu and it has 4 significant figures.
Answer:
Molarity = 2.54 mol.L⁻¹
Solution:
Molarity is the amount of solute dissolved per unit volume of solution. It is expressed as,
Molarity = Moles / Volume of Solution ----- (1)
Data Given;
Mass = 187 g
Volume = 250 mL = 0.25 L
First calculate Moles for given mass as,
Moles = Mass / M.mass
Moles = 187 g / 294.185 g.mol⁻¹
Moles = 0.6356 mol
Now, putting value of Moles and Volume in eq. 1,
Molarity = 0.6356 mol ÷ 0.25 L
Molarity = 2.54 mol.L⁻¹
Answer:
Synthesis
Explanation:
That's the answer to that question
Ionization energy than calcium
<span>The answer is Mandy’s solution is a
Base/Alkaline solution. Alkaline solution turns
red litmus blue while acidic solution turns
blue litmus red. In acidic solution, the red litmus remains red while in
alkaline solution, the blue litmus remains blue. However, litmus paper can never tell you the exact pH
number of a solution</span>
