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oee [108]
3 years ago
8

The mass of a radioactive substance follows a continuous exponential decay model, with a decay rate parameter of 8.1% per day. f

ind the half-life of this substance (that is, the time it takes for one-half the original amount in a given sample of this substance to decay).
Chemistry
1 answer:
Elanso [62]3 years ago
5 0
The general equation for radioactive decay is;
N = N₀e^(-λt)
x - decay constant (λ) - rate of decay 
t-  time 
N - amount remaining after t days , since we are calculating the half life, amount of time it takes for the substance to to be half its original value, its N₀/2
N₀ - amount initially present 
substituting the values 
N₀/2 = N₀e^(-0.081t)
0.5 = e^(-0.081t)
ln (0.5) = -0.081t
-0.693 = -0.081t
t = 0.693 / 0.081 
  = 8.55
half life of substance is 8.55 days 
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7th grade science , please don’t get the answer from the internet :(
Liula [17]

Answer:

See the answer below

Explanation:

1. Organisms produce energy for cells by chemically breaking down and unlocking the energy locked-up within food materials in a process known as cellular respiration. The unlocked energy is then utilized for the cell's metabolic activities.

2. Cellular respiration can be aerobic or anaerobic.

Aerobic respiration involves the breakdown of carbohydrates in the presence of oxygen to yield energy in the form of ATP while carbon dioxide and water are produced as by-products.

        C_6H_1_2O_6 + 6O_2 --> 6CO_2 + 6H_2O + ATP

Anaerobic respiration involves the breakdown of carbohydrates in the absence of oxygen to produce ATP and lactic acid as a by-product. The lactic acid is later oxidized to carbon dioxide and water to prevent it from building up.

       C_6H_1_2O_6 -> 2C_3H_6O_3 + ATP

3. Photosynthesis and cellular respiration are both considered metabolic processes that take place in living organisms. However, photosynthesis is peculiar only to green plants and some algae while respiration is common to all living organisms. While photosynthesis is anabolic, that is, it involves the building up of materials; respiration is said to be catabolic because it involves the breaking down of materials.

During photosynthesis, inorganic products are utilized to produce carbohydrates for plants with oxygen gas released as a by-product according to the following equation:

       6CO_2 + 6H_2O --> C_6H_1_2O_6 + 6O_2

During respiration, the food taken by living organisms is broken down to unlock the energy in it for metabolic activities according to the following equation:

     C_6H_1_2O_6 + 6O_2 --> 6CO_2 + 6H_2O + ATP

7 0
2 years ago
2. Energy cost of plasma generation of NO, NO2, and NO3 in air (or air bubble) is about 20 eV per N-atom. 100 W plasma system ha
svet-max [94.6K]

Answer:

0.0933 moles/Litre

Explanation:

We assume that the number of moles of N- used is equal to the number of moles of Nitrogen containing compounds that are generated due to the fact that the nitrogen containing compound that are produced contain only one nitrogen in each atom. As such, finding the amount of nitrogen used up explains the amount of compound formed. This can  be expressed as follows:

Energy cost = \frac{20ev}{N- atom}

Given that:

Energy = 100 W for 60 minutes

100 W = 100 J/s

           = 100 J/s × (60 × 60) seconds

           = 3.6 × 10⁵ J

Let now convert 3.6 × 10⁵ J to eV; we have:

= ( 3.6 × 10⁵  × 6.242 × 10¹⁸ )eV

= 2.247 × 10²⁴ eV

So, number of N-atom used up to form compounds will now be:

= 2.247 × 10²⁴ eV  × \frac{1}{20eV} N-atom

= 1.123 × 10²³ N-atom

To moles; we have:

= \frac {1.123*10^{23}} {6.023*10^{23}}

= 0.186 moles

However, we are expected to leave our answer in concentration (i.e in moles/L)

since we are given 2L

So;   0.186 moles ⇒   \frac{0.186 moles}{2 Litre}

= 0.0933 moles/Litre

3 0
3 years ago
Explain how there can be so many different kinds of suntances in the world
Volgvan
Because people make those substance out of other things
6 0
3 years ago
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Nookie1986 [14]
B because inner core has metal and it’s solid
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3 years ago
Read 2 more answers
What is the name of the compound Ca(NO3)2 ?
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Answer: B) calcium nitrate

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3 years ago
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