Answer:
= 72900 years
Explanation:
- The half-life is the time taken by a radioactive material to decay by half the original amount.
- The half-life of plutonium-239 is 24300 years which means it takes 24300 years to decay by half the original amount.
To calculate the time taken for a mass of 8 kg to decay to 1 kg we use;
New mass = Original mass x (1/2) ^n, where n is the number of half-lives
Therefore;
1 kg = 8 kg × (1/2)^n
1/8 = (1/2)^n
solving for n;
n =3
Therefore;
Time = 3 × 24300 years
= 72900 years
It will, therefore, take 72900 years for 8 kg of plutonium-239 to decay to 1 kg.
Answer:
D. Scientific notation is a way of writing large and small numbers
<span>False. Foods that allow microorganism to grow are not called parasites. Parasites are organisms that feeds on the nutrients of its host.
For example leeches. They suck on our blood.
</span>Foods that allow microorganism to grow are called <span>potentially hazardous foods. They are high in protein and moisture and are slightly acidic.
For example hamburgers. They are high in protein and moisture.</span>
Answer:Sodium Bicarbonate
Explanation:Crack is manufactured by using Sodium Bicarbonate (NaHCO3) to remove hydrochlorides to create a crystalline form of cocaine that can be smoked.
15 grams of NH3 can be dissolved
<h3>Further explanation</h3>
Given
50 grams of water at 50°C
Required
mass of NH3
Solution
Solubility is the maximum amount of a substance that can dissolve in some solvents. Factors that affect solubility
- 1. Temperature:
- 2. Surface area:
- 3. Solvent type:
- 4. Stirring process:
We can use solubility chart (attached) to determine the solubility of NH3 at 50°C
From the graph, we can see that the solubility of NH3 in 100 g of water at 50 C is 30 g
So that the solubility in 50 grams of water is:
= 50/100 x 30
= 15 grams
