Answer:- 9.4 minutes.
Solution:- Radioactive decay obeys first order reaction kinetics and the equation used to solve this type of problems is:

where, k is decay constant and t is the time.
is the initial amount of the radioactive substance and N is the remaining amount.
Since the value of decay constant is not given, so we need to calculate it first from given half life by using the formula:

where
stands for half life.
Given half life is 3.0 minutes.
So, 

Let's plug in the values in the first order reaction equation and solve it for t.

It could also be written as:



k = 9.4 min
So, the radioactive substance would take 9.4 minutes to decay from 40.0 grams to 4.5 grams.
Sodium Chloride is 0.4948 kJ/mol while Sodium Thiosulfate Pentahydrate is 0.2059 kJ/mol. Therefore, Sodium Chloride could store more energy on a per gram basis.
A. Burning a match because it changes its form
Answer:
A. 140,800 J
Explanation:
Specific heat of a material is defined as the amount of energy required to increase in 1°C 1kg of the material. <em>For wood there are required 1760J perkg per °C.</em>
The equation is:
Q = C*m*ΔT
<em>Where Q is heat in Joules,</em>
<em>C is specific heat (1760J/kg°C),</em>
<em>m is mass (2kg)</em>
<em>ΔT is change in temperature (50°C - 10°C = 40°C)</em>
Replacing:
Q = 1760J/kg°C*2kg*40°C
Q = 140800J
Right option is:
<h3>A. 140,800 J
</h3>
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Answer:
The correct option is;
b. The particles are positively and negatively charged, have high compressibility, and spread out to fill a container
Explanation:
Plasma are gases that contain positively and negatively charged particles. Therefore, plasma flow drift in space such that plasma. like gases has no characteristic shape or volume but takes the shape and fills the entire volume of a container in which it is placed
Other characteristics of plasma are that plasma is a conductor of electricity and magnetic fields can therefore exist in plasma due to the fact that plasma are made of atoms in which part or all of the electrons have been removed leaving the ions to roam freely in a container.