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nadezda [96]
3 years ago
15

Based on table N of the reference tables what is the number of hours required for 42k (potassium -42) to undergo three half-life

periods
Chemistry
1 answer:
skelet666 [1.2K]3 years ago
3 0

The number of hours required : 37.2 hours

<h3>Further explanation</h3>

Given

⁴²K (potassium -42)

Required

The number of hours

Solution

The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.  

Usually, radioactive elements have an unstable atomic nucleus.  

Based on Table N(attached), the half-life for ⁴²K is 12.4 hours, which means half of a sample of ⁴²K will decay in 12.4 hours

For three half-life periods :

\tt 3\times 12.4=37.2~hours

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Identify the compounds that are soluble in both water and hexane.
dlinn [17]

Answer:

The compound which are boh soluble in water and hexane is

B. Ethanol and 1-propanol  

Explanation:

The compounds ethanol and 1-propanol are soluble in both hexane and water.

It is soluble in water as both  consists of polar end due to hydrogen bonding present in the  -OH functional group.

and both are soluble in hexane as they contain a non polar end and the alliphatic hydrocarbon chain in them.

The solubility of alcohols varies in increasing order as the hydrocarbon chain increases. And becaue of this it becomes more non polar.

Non polar properties decreases for branched molecules.

so, the correct option is ethanol and 1-propanol.

3 0
4 years ago
How many moles are there in 7.5 L Of H2
True [87]
So multiply number of moles x number of atoms/mole = 1.8066 x 10^24 atoms of H2. One mole of any gas at STP has a volume of 22.4 L. So first determine the number of moles of gas you have.
for example do 7
7.5 \div 22.4
that 's what I think
3 0
3 years ago
Experiments were carried out in which a beam of cathode rays was first bent by a magnetic field and then bent back by an electro
Sergio039 [100]

a. the ratio of mass to charge of an electron

Explanation:

The experiment permitted the direct measurement of the ratio of mass to charge of an electron.

  • The charge to mass ratio of an electron was determine by accelerating a beam of cathode rays in magnetic and electric fields.
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learn more:

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6 0
3 years ago
The pH of a solution is 3.81. What is the OH concentration in the solution?​
disa [49]

Answer:

6.46 × 10⁻¹¹ M

Explanation:

Step 1: Given data

pH of the solution: 3.81

Step 2: Calculate the pOH of the solution

We will use the following expression.

pH + pOH = 14.00

pOH = 14.00 - pH = 14.00 - 3.81 = 10.19

Step 3: Calculate the concentration of OH⁻ ions

We will use the definition of pOH.

pOH = -log [OH⁻]

[OH⁻] = antilog -pOH = antilog -10.19 = 6.46 × 10⁻¹¹ M

3 0
3 years ago
How many moles are in 3.90 x1030 atoms of Zn?
zaharov [31]
Explanation:
The problem basically wants you to find a way to convert between the number of atoms present in the sample and the number of moles they are equivalent to.
To convert between atoms and moles we use something called Avogadro's constant, which basically acts as the definition of a mole.
More specifically, in order to have one mole of an element you need
6.022 x 10^23 atoms of that element. You can thus use this number as a conversion factor to take you from atoms to moles or vice versa.
In your case, you will have


3.90 x 10^ 26 atoms Zn x 1 mole Zn ( Avogrado’s constant) / 6.022 x 10^23 atoms Zn

= 6.5 x 10^8 is the answer
7 0
3 years ago
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