<h3>Answer:</h3>
18.75 grams
<h3>Explanation:</h3>
- Half-life refers to the time taken by a radioactive material to decay by half of the original mass.
- In this case, the half-life of element X is 10 years, which means it takes 10 years for a given mass of the element to decay by half of its original mass.
- To calculate the amount that remained after decay we use;
Remaining mass = Original mass × (1/2)^n, where n is the number of half-lives
Number of half-lives = Time for the decay ÷ Half-life
= 40 years ÷ 10 years
= 4
Therefore;
Remaining mass = 300 g × (1/2)⁴
= 300 g × 1/16
= 18.75 g
Hence, a mass of 300 g of an element X decays to 18.75 g after 40 years.
Answer:
a. 0.68 M NaCl solution
Explanation:
The tonicity of a solution can either be hypotonic, hypertonic and isotonic. Hypertonic solution is a solution which possesses a higher concentration of solute in relation to another solution.
According to this question, a solution is said to contain 0.15 M NaCl solute. This means that a solution that will be hypertonic to this solution will have a much more concentration of solute, which based on the options provided is the 0.68 M NaCl solution.
C
Immunization shots are given to ensure immunity against future attacks on the body against the disease in which the vaccine is made.
Explanation:
The vaccine prepares the body by giving immune cells memory against the disease agent. The vaccine achieves this by introducing an attenuated form of the agent of the disease into the body. This means the introduced disease agents cannot cause disease but are enough to evoke an immune response from the body. The immune system, after eradicating the attenuated disease agent from the body, acquires memory such that it fights a real-world disease agent in case of infection.
Learn More:
For more on vaccines check out;
brainly.com/question/1476591
brainly.com/question/11378151
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