The amount of substance present in a certain sample can be calculated through the equation,
A(t) = A(o)(0.5)^(t/h)
where At is the amount now, Ao is the original amount, t is the number of years and h is the half-life.
For a substance to at most 50% of the original amount, we get the half-life value.
At/Ao = 0.5 = 0.5^(4.5/h)
h = 4.5 billion.
All values below 4.5 billion as half-life are accepted. From the given list, the substances that would be less than 50% now are:
<em>Uranium - 238 ; Uranium -235 and ; Postassium-40</em>
3937.008 inches. Should be correct since I just typed it into google
Answer:
8.90 M
Explanation:
Step 1: Given data
-
Initial concentration (C₁): ?
- Initial volume (V₁): 635 mL = 0.635 L
- Final concentration (C₂): 5.00 M
- Final volume (V₂): 1.13 L
Step 2: Calculate the initial concentration
We have a concentrated NaCl solution and we want to prepare a diluted one. We will use the dilution rule.
<em>
C₁ × V₁ = C₂ × V₂
</em>
C₁ = C₂ × V₂ / V₁
C₁ = 5.00 M × 1.13 L / 0.635 L
C₁ = 8.90 M
V=84.0 mL = 84.0 cm³
m=609.0 g
p=m/v
p=609.0/84.0=7.25 g/cm³
Answer:
B. 3.0 g/ml
Explanation:
density formula: mass/volume
15/5=3