You have 500,000 atoms of a radioactive substance. After 2 half-lives have past, how many atoms remain?
2 answers:
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Answer:
5.758 is the density of the metal ingot in grams per cubic centimeter.
Explanation:
1) Mass of pycnometer = M = 27.60 g
Mass of pycnometer with water ,m= 45.65 g
Density of water at 20 °C = d =
1 kg = 1000 g
Mass of water ,m'= m - M = 45.65 g - 27.60 g =18.05 g
Volume of pycnometer = Volume of water present in it = V
2) Mass of metal , water and pycnometer = 56.83 g
Mass of metal,M' = 9.5 g
Mass of water when metal and water are together ,m''= 56.83 g - M'- M
56.83 g - 9.5 g - 27.60 g = 19.7 g
Volume of water when metal and water are together = v
Density of metal = d'
Volume of metal = v' =
Difference in volume will give volume of metal ingot.
v' = v - V
Since volume cannot be in negative .
Density of the metal =d'
=
Answer:
325mg of Aspririn
Explanation:
First you should note the information that the problem gives you:
- The bottle of Aspirin has 5gr (grains)
- 1gr(grain) = 65mg (miligrams)
Also, the problem is asking about how many aspirin are in 5 gr (grains), so you should use a conversion factor, as follows:
-First you should put the quantity you need to convert:
-Then you write the denominator of the conversion factor that must have the same units that you want to convert, in this case gr:
-Then you write the numerator with the units that you want to obtain and the numerical equivalence between the units, in this case:
-Finally you multiply numerators and divide by denominators: