Answer:
The mass of the radioactive sample after 40 minutes is 12.8 g.
Step-by-step explanation:
The mass of the sample can be found by using the exponential decay equation:

Where:
N(t): is the amount of the sample at time t =?
N₀: is the initial quantity of the sample = 120 g
t = 40 min
λ: is the decay constant = 0.056 min⁻¹
Hence, the mass of the sample after 40 min is:

Therefore, the mass of the radioactive sample after 40 minutes is 12.8 g.
I hope it helps you!
You have to subtract 3.2 from 3.5 to get x. 0.3+ 3.2=2.5 so x=0.3
Answer:
<u><em>They each had </em></u><u><em>1/20 of the original meal</em></u>
Step-by-step explanation:
<u><em>To begin, </em></u><u><em>there are 4 people</em></u><u><em>. Her siblings, and herself. She is </em></u><u><em>splitting the 1/5 leftover</em></u><u><em> to feed them. To do this, we simply </em></u><u><em>take 1/5 and put it into a fraction to get 0.2</em></u><u><em>. Next, we can </em></u><u><em>put 0.2 / 4 into a calculator</em></u><u><em> to get how much each person can get.</em></u>
<u><em>0.2 / 4 = 0.05.</em></u>
<u><em>Now, we need to </em></u><u><em>turn it into a fraction</em></u><u><em> to find out how much they had in fraction form of the original.</em></u>
<u><em>0.05 = 1/20</em></u>
<u><em>They each had </em></u><u><em>1/20 of the original meal</em></u>
Answer:
Option D. No,they are not similar because their side lengths are not proportional.
Step-by-step explanation:
we know that
If two figures are similar, then the ratio of its corresponding sides is proportional and its corresponding angles are congruent
In this problem If the rectangles are similar
then
The ratio of its corresponding lengths must be equal to the ratio of its corresponding heights
<u><em>Verify</em></u>

therefore
The rectangles are not similar because their side lengths are not proportional.
Answer:
Amount of NaCl = 23.376 gram
Step-by-step explanation:
Given:
Molarity = 4M
Volume of solution = 100 ml
Find:
Amount of NaCl
Computation:
Molar mass of Na = 22.99 g/mole
Molar mass of Cl = 35.45 g/mole
Molar mass of NaCl = 22.99 + 35.45
Molar mass of NaCl = 58.44 g/mole
Molarity = [moles of solute / volume of solute(ml)]1,000
4 = [moles of solute / 100]1000
Moles of solute = 0.4
moles of solute = Mass of solute / molar mass
0.4 = Amount of NaCl / 58.44
Amount of NaCl = 23.376 gram