1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
natta225 [31]
3 years ago
7

As part of her nuclear stress test, Simone starts to walk on the treadmill. When she reaches the maximum level, Paul injects a r

adioactive dye with201Tl with an activity of 72 MBq . The radiation emitted from areas of her heart is detected by a scanner and produces images of her heart muscle. After Simone rests for 3 h, Paul injects more dye with 201Tl and she is placed under the scanner again. A second set of images of her heart muscle at rest is taken. When Simone's doctor reviews her scans, he assures her that she had normal blood flow to her heart muscle, both at rest and under stress.
Part A
If the half-life of 201Tl is 3.0 days, what is its activity, in megabecquerels after 3.0 days?
Express the activity to two significant figures and include the appropriate units.

Part B
What is its activity in megabecquerels after 6.0 days?
Express the activity to two significant figures and include the appropriate units.
Chemistry
1 answer:
Naya [18.7K]3 years ago
3 0

Answer:

Part A: 36 MBq; Part B: 18 MBq

Explanation:

The half-life is the time it takes for half the substance to disappear.

The activity decreases by half every half-life

A =Ao(½)^n, where n is the number of half-lives.

Part A

3.0 da = 1 half-life

A =  Ao(½) = ½ × 72 MBq = 36 MBq

Part B

6.0 da = 2 half-lives

A = Ao(½)^2 = ¼ × 72 MBq = 18 MBq

You might be interested in
How do plants and animals help to maintain a balance of carbon dioxide in the atmosphere
Tom [10]
Well all I know that animals take in oxygen and take out carbon dioxide and plants take in carbon dioxide and take out oxygen
3 0
3 years ago
What is the electric field (in N/C) at a point 5.0 cm from the negative charge and along the line between the two charges?
Natali [406]

Answer: E = 2.455 x 10^5 N/C

Explanation:

q1 = 1.2x10^-7C

q2 = 6.2x10^-8C

Electric field, E = kQ/r²

where k = 9.0x10^9

since the location is (27 - 5)cm from q1

hence electric field, E1 = k*q1/r²

E1= (9x10^9 x 1.2x10^-7)/(0.22)² = 22314.05 N/C

for q2:

E1 = k*q2/r²

E2 at 5cm

E2 = (9x10^9 x 6.2x10^-8)/(0.05)² = 223200 N/C

Hence, the total electric field at 5cm position is

E = E1 + E2

E = 22314.05 + 223200 = 245514.05 N/C

E = 2.455 x 10^5 N/C

4 0
3 years ago
The degree of unsaturation, or index of hydrogen deficiency, is the number of pi bonds plus rings in a molecule. Specify the deg
yaroslaw [1]

Explanation:

The degree of unsaturation is given as;

Degree of unsaturation = (2C + 2 + N - H - X) / 2

(a) C5H6

Using the formular above;

Degree of unsaturation = [ 2(5) + 2 - 6] / 2

Degree of unsaturation = [ 12 - 6 ] / 2 = 3

(b) C10H6Cl2

Using the formular above;

Degree of unsaturation = [ 2(10) + 2 - 6 -2 ] / 2

Degree of unsaturation = [ 22 - 8 ] / 2 = 7

(c) C4H3NO

Using the formular above;

Degree of unsaturation = [ 2(4) + 2 - 3 -1 ] / 2

Degree of unsaturation = [ 10 - 4 ] / 2 = 3

Note: Oxygen is ignored because its presence has no effect on the degree of unsaturation.

5 0
3 years ago
What conditions will cause a redox reaction to be nonspontaneous?
kherson [118]
The answer is B for the apex answer
7 0
3 years ago
An ionic compound has the general form, xcly. which option for x and y correctly completes the formula?
igor_vitrenko [27]
Answer:
Case 1:
            X  =  Any element from Group I
            
                       i)    H
                       ii)   Li
                       iii)  Na
                       iv)  K
                       v)   Rb
                       vi)  Cs

            Y  =  1

Case 2:
            X  =  Any element from Group II
            
                       i)    Be
                       ii)   Mg
                       iii)  Ca
                       iv)  Sr
                       v)   Ba
                       vi)  Ra

            Y  =  2

Case 3:
            X  =  Any element from Group III
            
                       i)    B
                       ii)   Al
                       iii)  Ga
                       iv)  In
                       v)   Ti

            Y  =  3

Explanation:
                   The general formula given is as follow,

                                                    XCly

So, if X has +1 oxidation state, then it will require only one Cl atom with oxidation number -1 to form a neutral compound, therefore, y = 1.

If X has +2 oxidation state, then it will require two Cl atoms with oxidation number -1 to form a neutral compound, therefore, y = 2.

If X has +3 oxidation state, then it will require three Cl atoms with oxidation number -1 to form a neutral compound, therefore, y = 3.
8 0
4 years ago
Other questions:
  • In a solution with a pH of 4, the [OH-] is:<br>1x 10-10<br>1x 10-4<br>10<br>- 1x 10-8<br>​
    15·1 answer
  • Calculate the molarity (M) of a 600 ml solution of 0.54 moles of H2SO4.
    6·1 answer
  • 7. Convert 5.2 cm of magnesium (Mg) ribbon to mm of Mg ribbon.
    9·2 answers
  • How many moles are in 5.22 x 10^24 atoms<br> of H2O?
    6·1 answer
  • If parents wanted to pick their child's traits like hair color, gender, eye color, what would doctors have to do?
    11·1 answer
  • Why can three atoms of magnesium have different masses?
    10·2 answers
  • How many mol of phosphorus are obtained if 74.85 mol of carbon is used​
    10·1 answer
  • You have two solutions of chemical A. To determine which has the highest concentration of A (molarity), which of the following m
    6·1 answer
  • What is the average “lifespan” of the following cells:
    12·1 answer
  • The energy necessary for photosynthesis to take place is provided by
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!