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2 years ago

9

Half life in chemistry I wasn't here when we did this

1 answer:

tatuchka [14]2 years ago

6 0

A half-life is the amount of time it takes for half of a substance to decay.

1.) After one half-life - 13.5mg.
After two - 6.75mg
Three - 3.375mg

2.) 250mg of Iron-59 will remain.

3.) 14 days is the half-life of Phospherous-32.

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Noble Gases (18): (Name all noble gases)

Paul [167]

Answer :

The Noble gasses are Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn).

When air is cold, Oxygen liquefies first at $-182^oC$ . $N_2$ liquefies at $-195^oC$ . About 1% of the air is still gas composed of the noble gas Argon, Ar.
One noble gas was discovered on the sun. It’s spectrum was identify first. This is Helium, He.
One of noble gas is radioactive and seeps up your basement floors and walls. It is Radon, Rn.
This noble gas is used in electronic flashes and other bright lights. It is Xenon, Xe.
This noble gas is best known for its orange color in gas discharge tubes. It is used for signs that bear its name. It is Neon, Ne.

3 0

3 years ago

Two samples of the same compound are compared. what does the data represent? sample 1: 24.22 g carbon and 32.00 g oxygen sample

goblinko [34]

According to law of definite proportion:

In a compound, elements are always arranged in fixed ratio by mass.

Here, sample 1 has 23.22 g Carbon and 32.00 g Oxygen.

Converting mass into number of moles:

Molar mass of carbon is 12 g/mol and that of oxygen is 16 g/mol thus,

$n_{C}=\frac{m_{C}}{M_{C}}=\frac{24.22 g}{12 g/mol}\approx 2 mol$

Similarly, number of moles of oxygen will be:

$n_{O}=\frac{m_{O}}{M_{O}}=\frac{32 g}{16 g/mol}=2 mol$

The ratio of number of moles of carbon and oxygen will be:

$C:O=n_{C}:n_{O}=2:2=1:1$

Therefore, formula of compound will be CO.

Sample 2:

It has 36.22 g Carbon and 48.00 g Oxygen.

Converting mass into number of moles:

Molar mass of carbon is 12 g/mol and that of oxygen is 16 g/mol thus,

$n_{C}=\frac{m_{C}}{M_{C}}=\frac{36.22 g}{12 g/mol}\approx 3 mol$

Similarly, number of moles of oxygen will be:

$n_{O}=\frac{m_{O}}{M_{O}}=\frac{48 g}{16 g/mol}=3 mol$

The ratio of number of moles of carbon and oxygen will be:

$C:O=n_{C}:n_{O}=3:3=1:1$

The formula of compound will be CO.

Therefore, it is proved that carbon and oxygen are present in fixed ratios in both the samples.

4 0

2 years ago

Does anyone know how to write out the formula for these?? not just the answer x

Tju [1.3M]

Idk how to write the formula I had this same question

5 0

2 years ago

A student dilutes 50.0 mL of a 0.10 mol/L to 0.010 mol/L. Which statement is true?

VLD [36.1K]

The total amount of solute decreases.

6 0

3 years ago

Which of the following are examples of electromagnetic waves?

liubo4ka [24]

Answer:

C

Explanation:

Electromagnetic waves travel at the speed of light and do not require molecules (gas, solid or liquid) to vibrate and travel.

Soundwaves when singing or from thunder vibrate particles to reach our ears and are known as mechanical waves.

8 0

3 years ago