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zubka84 [21]
2 years ago
11

There are 5.0g of I-131 left after 40 days. How many grams were in the original sample if the half-life is 8 days?

Chemistry
1 answer:
Gre4nikov [31]2 years ago
5 0
5.0=mo(1/2) ^ 5
5.0=mo (.031)
about 160/161.29
You might be interested in
Determine the molecular formula for the unknown if the molecular mass is 60.0 amu and the empirical formula is ch2o.
mezya [45]

Answer:

The molecular formule for this unknow molecule is C2H4O2

Explanation:

The empirical formula is CH2O  ( or better said CnH2nOn)

This means there are 3 elements in the formula of this molecule

⇒ Carbon (C) with a Molar mass of 12 g/mole

⇒ Hydrogen (H) with a Molar mass of 1 g/mole

⇒ Oxygen (O) with a Molar mass of 16 g/mole

We can also notice that the amount of hydrogen should 2x the amount of carbon ( also 2x the amount of oxygen).

The mass of the empirical formule = 12g/ mole + 2* 1 g/mole + 16 g/mole = 30 g/mole

To know what number is n in CnH2nOn we should divide the molecular mass by the empirical mass:

60 g/mole / 30g/mole = 2

this means n = 2

and this will give a molecular formule of C2H4O2  

We can control this to calculate the molecular mass:

2*12 + 4* 1 + 2*16 = 24 + 4 + 32 = 60 g/mole

The molecular formule for this unknow molecule is C2H4O2

5 0
3 years ago
True or false; when something heats up, New energy is created, and when something cool down, Energy is destroyed.
Ann [662]

Answer:

This is false.

Explanation:

This statement directly opposes the first law of thermodynamics which states that energy can neither be created nor destroyed, but can transfer from one source to another.

4 0
2 years ago
Draw a structural formula for the alkene you would use to prepare the alcohol shown by hydroboration/oxidation.
Nastasia [14]

Answer:

See explanation

Explanation:

The question is incomplete because the image of the alcohol is missing. However, I will try give you a general picture of the reaction known as hydroboration of alkenes.

This reaction occurs in two steps. In the first step, -BH2 and H add to the same face of the double bond (syn addition).

In the second step, alkaline hydrogen peroxide is added and the alcohol is formed.

Note that the BH2 and H adds to the two atoms of the double bond. The final product of the reaction appears as if water was added to the original alkene following an anti-Markovnikov mechanism.

Steric hindrance is known to play a major role in this reaction as good yield of the anti-Markovnikov like product is obtained with alkenes having one of the carbon atoms of the double bond significantly hindered.

5 0
2 years ago
Lewis structure for 2O2
Mrrafil [7]

the big number describes the number ratio in a chemical equation

so for example,

2H2 + O2 --> 2H2O means

2 moles of hydrogen reacts with one mole of oxygen to form 2 moles of water

and as you know, the small (subscript) number determines the number of atoms of that element in one molecule of a compound

so I believe that drawing a normal lewis structure ( O=O ) should be correct

6 0
3 years ago
Read 2 more answers
Isopropyl alcohol is a clear liquid with a density of 0.78 g/cm3. If the same small sphere (with a density of 0.88 g/cm3) is dro
Burka [1]
Ayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
6 0
3 years ago
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