Answer:
After 48 hours amount left = 6.25 g
Explanation:
Given data:
Half life of potassium = 12 hours
Total mass = 100 g
Mass left after 48 hours = ?
Solution:
Number of half lives passed:
Number of half lives = Time elapsed / half life
Number of half lives = 48 hours/ 12 hours
Number of half lives = 4
At time zero = 100 g
At first half life = 100 g/ 2 = 50 g
At 2nd half life = 50 g/2 = 25 g
At 3rd half life = 25 g/2 = 12.5g
At 4th half life = 12.5 g/2 = 6.25 g
A forest ecosystem can support a limited number of bears. This is because available energy is lost from one trophic level to the next. (flies, trout, then bears)
Answer:
1.2 mL
Explanation:
<em>This is a problem of simple dilution. The dilution principle simply agrees that the number of moles before dilution must be equal to the number of moles after dilution.</em>
Recall that: number of moles = mass/molar mass or molarity x volume.
Hence, for the dilution principle:
initial molarity x initial volume = final molarity x final volume.
In this case, initial molarity of NaOH = 1 M, initial volume = ?, final molarity = 0.1 M, final volume = 12.0 mL.
Initial volume = final molarity x final volume/initial molarity
= 0.1 x 12/1 = 1.2 mL
It thus means that 1.2 mL of 1 M NaOH would be taken and then diluted up to 12.0 mL mark by the addition of distilled water in order to produce 12.0 mL, 0.10 M NaOH solution.
Answer:
true
Explanation:
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
