Answer:
3 half-lives
Explanation:
The half-life is the time that it takes to a radioactive element to decay to half of its initial amount.
Let's suppose we start with 64 g of the radioactive element.
- After 1 half-life, the mass of the element will be 32 g.
- After 2 half-lives, the mass of the element will be 16 g.
- After 3 half-lives, the mass of the element will be 8 g.
Based on atomic mass
Explanation:
Elements were arranged on the first periodic table based on their atomic masses.
The mass of an atom is made up of the mass of the nucleus which contains the protons and neutrons.
- Dimitri Mendeleev was the first person credited for arranging elements periodically.
- He was said to have been inspired while playing his game of solitaire on a train.
- On his table, he left spaces for the atomic masses of elements not yet discovered.
- Today, the periodic table is based on the atomic numbers of elements. This is the number of protons in an atom.
Learn more:
Periodic table brainly.com/question/2690837
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By 1.23 x 1024 you mean 10 to the power of 24 molecules? If so all you need to do is divide the number of molecules you have by Avagadros number, 6.022 x 10^23. This will give you the mols of water, or the mols of anything, since there is always 6.022 x 10^23 molecules in 1 mol of substance.
1.23x10^24 atoms/6.022x10^23 atom/mol = 2.04 mol H20
Answer:
0.1 M
Explanation:
Molarity = number of moles / litres of solution.
4 g of calcium bromide = 0.02 mol
(found by dividing 4 g by the atomic mass of CaBr2, which is 199.886)
200 mL of solution = 0.2 litres
Molarity = 0.02 mol / 0.2 L = 0.1 M
Answer: 1. AgF + CaCl2 = AgCl + CaF2
2. C2H4 +O2 = CO2 +H2O
3. K2S = K+S
4. O2 + Mg = MgO
5. Mg + AlBr3 = MgBr2 + Al
6.C2H6O + O2= CO2 + H2O
7.Li2SO4 + MgCl2= Li2SO4 + MgCl2
8.HCl + Zn= H2 + ZnCl2
Explanation:
Balance the equation
Write down your given equation.
Write down the number of atoms per each element that you have on each side of the equation.
Always leave hydrogen and oxygen for last.
If you have more than one element left to balance:
Add a coefficient to the single carbon atom on the right of the equation to balance it with the 3 carbon atoms on the left of the equation.
Balance the hydrogen atoms next.
Balance the oxygen atoms.
