After 2 days, 10g of radioactive chemical is present. Three days later, 5g is present. How much of the chemical was present initially, assuming the rate of disintegration is proportional to the amount present?

Question 18: Uranium-232 is a radioactive isotope with a half life of 68.9 years. How long in years will it take for 40% of a sample of U-232 to decay? 51.1 x years

A titration of 25.00 mL of an unknown HCl solution with 0.1550 M NaOH requires 24.00 mL of NaOH to reach completion. Write the overall balanced AND net ionic equations. (Note: STRONG acid and base)

Iodine-131 is used in the diagnosis and treatment of thyroid disease and has a half-life of 8.0 days. If a patient with thyroid disease consumes a sample of Na 131 I containing 10. μ g 131 I, how long will it take for the amount of 131 I to decrease to 1/100 of the original amount?

If a tree dies and the trunk remains undisturbed for 1.635 × 10⁴ years, what percentage of the original ¹⁴C is still present? (The half-life of ¹⁴C is 5730 years.)

The half-life of bromine-74 is 25 minutes.  How much of a 40 cpm sample is still active after 75 minutes?