Answer:
is the activity, measured in of a 50 mg sample of 90-Sr.
Explanation:
Half life of the 90-Sr ,
Activity coefficient of the 90-Sr = 
Mass of 90-Sr = 50 mg = 0.050 g
Molecular mass of 90-Sr = 90 g/mol
Moles of 90-Sr =
Number of atom in 0.0005555 moles of 90-Sr:
1 year = 
Activity measured in atoms per seconds:
= Number of atoms ×
Answer:
appx. 1.07 moles
Explanation:
175g of molecule Ca(NO3)2
To find the # of moles, use stoichoimetry.
1. We need the molar mass of Ca(NO3)2.
Ca mass: 40.08 g
NO3 mass: N + 3(O) --> 14.01 + 3(16.00) --> 62.01
Molar mass = Ca + 2(NO3) --> 40.08 + 2(62.01) --> 164.1 g
2. write out the calculation
175g Ca(NO3)2 * (1 mole Ca(NO3)2)/(molar mass of Ca(NO3)2)
175 g Ca(NO3)2 * (1 mole Ca(NO3)2)/(164.1 g Ca(NO3)2)
The g units cancel out and we're left with moles.
Simply perform the calculation now: 175*1/164.1 ≅1.07 moles
Answer:
U A G C C A U C G G A U C C G A U
Explanation:
In DNA, A=T, C=G, and vice versa. RNA has U instead of T. So dna to rna: adenine = uracil, thymine = adenine, cytosine = guanine, and guanine = cytosine.
Gasoline will not dissolve in water because gasoline has more density then the water
