Answer: 20 mg Te-99 remains after 12 hours.
Explanation: N(t) = N(0)*(1/2)^(t/t1/2)
N(t) = (80 mg)*(0.5)^(12/6)
N(t) = 20 mg remains after 12 hours
On the periodic table it is the number on the bottom of the element.
<span>If you know the amount of neutrons you can add it to the number of protons to find the atomic mass NUMBER, which is a good approximate of the atomic mass. </span>
Answer:
672 g
Explanation:
We can calculate the mass of water that can be warmed from 25.0°C to 37.0°C by the addition of 8,064 calories using the following expression.

where,
c: specific heat of the water
m: mass
ΔT: change in the temperature

The mass of water that can be warmed under these conditions is 672 grams.
Answer:
Compound
Explanation:
The given specie is a compound.
A compound is made up of two or more kinds of atoms/elements joined together in a definite grouping.
- The properties of a compound are distinct and different from those of the individual elements that are combined in its make-up.
- For this given specie, the elements are carbon, hydrogen and oxygen.
- So, this is a compound.
Elements are distinct substances that cannot be split - up into simpler substances. Such substances consist of only one kind of atom