From the molarity and volume of HClO4, we can determine how many moles of H+ we initially have:
0.18 M HClO4 * 0.100 L HClO4 = 0.018 moles H+
We can determine how many moles of OH- we have from the molarity and volume of LiOH:
0.27 M LiOH * 0.030 L LiOH = 0.0081 moles OH-
When the HClO4 and LiOH neutralize each other, the remaining will be
0.018 moles H+ - 0.0081 moles OH- = 0.0099 moles of excess H+
This means that the molarity [H+] will be
[H+] = 0.0099 moles H+ / (0.100 L + 0.030 L) = 0.07615 M
The pH of the solution will therefore be
pH = -log [H+] = -log 0.07615 = 1.12
When preparing diluted solutions from concentrated solutions , we can use the following equation;
c1v1 =c2v2
Where c1 and v1 are the concentration and volume of the concentrated solution
c2 is the concentration of the diluted solution to be prepared
v2 is the volume of the diluted solution
Substituting the values;
12.0 M x v1 = 0.339 M x 100 mL
v1 = 2.825 mL needs to be taken from the stock solution
Answer:
Independent Variable: Grade Level
Dependent Variable: Growth in height
Hypothesis: Students in [Insert the grade level you believe will grow the quickest here] will experience the quickest growth in height.
Explanation:
Independent variables are the factors in which you manipulate to gain your results, in this case you would be changing the grade level you would observe to see the height.
Dependent variables are the factors that respond to changes in the independent variables. You don't control these events, you simply observe them. In this case, you merely observe the growth in height in accordance to the different grade levels you observe.
For the hypothesis, you would create your own hypothesis based on a guess you have. You create a hypothesis not based on the data, but on what you believe will be correct before doing the experiment. It doesn't have to be the correct answer, but just your thoughts.
Answer:
Age of rock = 722 million years old
Explanation:
Using the formula; <em>fraction remaining = 0.5ⁿ</em>
where n = number of half lives elapsed.
However, from the given values, fraction remaining = 1.000 - 0.0105
fraction remaining = 0.9895
Substituting in the formula to determine the number of half-lives:
0.9895 = 0.5ⁿ
log 0.9895 = n log 0.5
-0.0045842 = -0.30103 n
number of half lives elapsed, n = 0.0152
Therefore age of rock = 0.0152 x 4.75 x 10¹⁰ years = 7.22 x10⁸ years
Age of rock = 722 million years old
