9. What is the amount of radioactive material remaining after 9 days in a radioactive sample with decay rate n = 25 (9) ²/2 modelled by the equation y = 25 a. 0.11 mg b. 0.19 mg 10. The simplified form of (az) (a³) i is: (aio) a. b. (az) C. 1.1 mg d. 2.2 mg C. (as) d. (a¹)

F. 2.5(JK) 12 What is HL? = 7H %3D

10. A =bh A' =bh or ans : %3D (h) 4h

H= V = 4 in B%3D 4 in SA = 12 in P= LA =

a radioactive element decays according to the fuction A(t)= A0 e-0.0319t, where t is in years. a. if 500 grams of the element are present initially, how much of the element would remain after 5 years? round to the nearest gram. b. find the half of the element. round to the nearest hundredth of a year.

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A earthquake is measured with wave amplitude of 1000 times as great as I0. What is the magnitude of this earthquake using Richter scale? A. 2.0 B. 2.5 C. 3.0 D. 3.33 The two liters solution contains 0.00004 moles of hydrogen ions. What is its pH level?A. 4.10 B. 4.40 C. 4.60 D. 6.80

1 1/2 = 7/12 C C =  ?

X = 2 S=0.5 X=1.8 Z =

Use the table to the right to answer the following question. How many kilograms of combustible sedimentary rock would be required to supply the energy needs of country A for 1 year? Item Energy released by burning 1 kg of a certain combustible sedimentary rock Energy (joules) 1.6x 10° nts Energy released by fission of 1 kg of a certain isotope 5.6x 1013 7x 10 1x 1021 4x 1020 al Energy released by fusion of hydrogen in 1 liter of water Country A annual energy consumption Country B annual energy consumption It would take approximately kilograms. ess (Use scientific noteipn. Use the multiplication symbol in the math palette as needed. Round to three decimal places as needed.)