Chromium-48 decays. After 6 half-lives, how much of the original nuclei would remain if we started with 600 g?

kenny6666 [7]

I will try my best to sovle this question...

Im Pretty sure it has to be A. it needs to balance it would not stand in place if not balanced.

3 0

3 years ago

A method used by the U.S. Environmental Protection Agency (EPA) for determining the concentration of ozone in air is to pass the

baherus [9]

Answer: 1. $9.08\times 10^{-6}$ moles

2. 90 mg

Explanation:

$O_3(g)+2NaI(aq)+H_2O(l) \rightarrow O_2(g)+I_2(s)+2NaOH(aq)$

According to stoichiometry:

1 mole of ozone is removed by 2 moles of sodium iodide.

Thus $4.54 \times 10^{-6}$ moles of ozone is removed by = $\frac{2}{1}\times 4.54 \times 10^{-6}=9.08\times 10^{-6}$ moles of sodium iodide.

Thus $9.08\times 10^{-6}$ moles of sodium iodide are needed to remove $4.54\times 10^{-6}$ moles of $O_3$

2. $\text{Number of moles of ozone}=\frac{0.01331g}{48g/mol}=0.0003moles$

According to stoichiometry:

1 mole of ozone is removed by 2 moles of sodium iodide.

Thus 0.0003 moles of ozone is removed by = $\frac{2}{1}\times 0.0003=0.0006$ moles of sodium iodide.

Mass of sodium iodide= $moles\times {\text {molar mass}}=0.0006\times 150g/mol=0.09g=90mg$ (1g=1000mg)

Thus 90 mg of sodium iodide are needed to remove 13.31 mg of $O_3$ .

3 0

2 years ago

Find the total number of atoms in a sample of cocaine hydrochloride, c17h22clno4, of mass 23.0 mg .

Nataliya [291]

From the periodic table:
mass of carbon = 12 grams
mass of hydrogen = 1 gram
mass of nitrogen = 14 grams
mass of oxygen = 16 grams
mass of chlorine = 35.5 grams
Therefore,
molar mass of c17h22clno4 = 17(12) + 22(1) + 35.5 + 14 + 4(16) = 339.5 grams

number of moles = mass / molar mass
number of moles = (23*10^-3) / (339.5)
number of moles = 6.77 * 10^-5 moles

number of atoms = number of moles * Avogadro's number
number of atoms = 6.77*10^-5 * 6.022*10^-23
number of atoms = 4.079 * 10^-27 atoms

3 0

3 years ago

How can you tell if an element has been oxidized or reduced in a reaction?

fomenos

Gaining of electrons is reduction and loss of electrons is oxidation.

Hope this helped! :)

7 0

3 years ago

A sodium atom and sodium ion have the same

Ilia_Sergeevich [38]

Answer:

a) number of neutrons

Explanation:

A sodium ion is formed when an electron is removed from a sodium atom. This means that the atom's number of electrons changes, but the number of neutrons remains unchanged.

However, as the number of electrons changes, the electric charge and the electronic structure change, which means that a sodium atom and a sodium ion do not have the same number of electrons, nor do they have the same electric charge or electronic structure.

Therefore, option a) is the correct option.

3 0

1 year ago