Answer:
Mass = 14.64 g
Explanation:
Given data:
Volume of solution = 1.25 L
Molarity of Solution = 0.15 M
Mass of CaF₂ = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
We will calculate the number of moles of CaF₂ and then determine the mass by using number of moles.
0.15 M = number of moles of solute / 1.25 L
number of moles of solute = 0.15 M × 1.25 L
number of moles of solute = 0.1875 mol/L × L
number of moles of solute = 0.1875 mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 0.1875 mol ×78.07 g/mol
Mass = 14.64 g
Answer: option D. 4.5 seconds.
Explanation:
The equilibrium reaction is H₂O ⇄ H₂ + O₂
The chemical equilibrium is a dynamic one. Two reactions are happening symultaneously: the forward reaction (H₂O → H₂ + O₂) ,to the right, and the reverse reaction (H₂O ← H₂ + O₂), to the left. At equilibrium both reactions have the same rate, which makes that the total, measurable quantity of reactants and products remain constant.
In the figure you see:
- The vertical axis measures concentration.
- The horizontal axis measures time (seconds).
- The two blue lines, the concentrations of H₂ and O₂, become flat (reach a zero slope) between 4 and 5 seconds.
- The red line, the concentration of H₂O, becomes flat, also, between 4 and 5 seconds.
- Hence, the concentrations of the reactant and the products do not change after that time meaning that the reaction has reached the equilibrium at about 4.5 seconds.
Answer:
9. Electron Affinity
10. The second option....
Answer:
A) 3.6 cm
Explanation:
Accuracy comes down to how precisely you can read the length on a given scale. Here since the smallest increment is centimeter, we can go only one decimal beyond to estimate. This is because you can usually estimate to only one decimal place beyond the closest marks on any measuring.
So, the answer should be 3.6 cm.
Here's a document that explains it well: https://www.auburn.wednet.edu/cms/lib03/WA01001938/Centricity/Domain/1360/1_Uncertainty.pdf
Hope that's right!
