<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.
5.64 (.) 10^14Hz. I hope this is correct. Sorry if i am all the way wrong. Enjoy your day and I hope you are coping with virtual learning because, I am struggling:)
Answer;
FeSO4 (aq) + H2 (g)
Explanation;
The reaction between iron and dilute sulfuric acid gives a salt and hydrogen gas. (iron (ii) sulfate and hydrogen gas).
The equation for the reaction is;
Fe(s) + H2SO4 (aq) = FeSO4(aq) +H2(g)
Answer:
893K=620 °C
Explanation:
PV=nRT
P=nRT/V
P= (1 mol* 0.0821* 298K)/15L P=1.63 atm
T=PV/nR
T=(1.63 atm*45 L)/(1 mol*0.0821)
T= 893K=620 °C
Answer:
kg & m/s
Explanation:
mass is measured in kg and speed is measured in m/s
