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
Paladinen [302]
3 years ago
13

A 0.133 pg sample of iron-59 produces 242 β-particles per second. what is the half-life of this isotope (in hours)

Chemistry
1 answer:
34kurt3 years ago
4 0
1070 hours.  
1 mole of iron-59 would mass 59 grams, so 0.133 picograms would be 0.133x10^-12 / 59 = 2.25x10^-15 moles of iron-59. Multiplying by Avogadro's number, we can determine the number of atoms of iron-59 we have, so: 2.25x10^-15 * 6.02214x10^23 = 1.35x10^9 
 Since we have 242 decays over a period of 1 second, we can divide the
number of atoms left by the original number of atoms
 (1350000000 - 242)/1350000000
 = 1349999758/1350000000
 = 0.999999820740741 
 And calculate the logarithm to base 2 of that quotient.
 ln(0.999999820740741)/ln(2)
 = -1.79259275281191x10^-7/0.693147180559945
 = -2.58616467481524x10^-7 
 The reciprocal of this number will be the half life in seconds. So
 -1/2.58616467481524x10^-7
 = -3866729.79388461 
 And dividing by 3600 (number of seconds in an hour) will give the half-life in
hours.
 -3866729.79388461 / 3600 = -1074.091609 
 So the half life in hours to 3 significant figures is 1070 hours.
 Dividing that figure by 24 gives a half life of 44.58 days which is in pretty close agreement to the official half-life of 44.495 days for iron-59.

You might be interested in
During the period from about 1800 to about 1865, the atomic weights of many elements were accurately measured. Why was this impo
tatiyna
I believe Mendeleev formed his periodic table by atomic weight (nowadays we do it by atomic number) so he likely used those values.
4 0
3 years ago
what is the main 'impurity' collected with the oil in distillation. PLEASE HELP IM IN END OF YEAR EXAM. II WILL GIVE BRAINLIEST
Zigmanuir [339]

Answer:

I think it is sulfur

Explanation:

5 0
3 years ago
Students in a science class learn that groundwater is an important source of drinking water for many communities. They construct
sveticcg [70]

Groundwater is also one of our most important sources of water for irrigation from septic tanks and toxic chemicals from underground storage tanks and leaky landfills ... Drinking contaminated groundwater can have serious health effects. If there is a leak, these contaminants can eventually make their way down

5 0
3 years ago
Calculate the molarity of a solution of Nach if it contains 7.2.g Nach in 100.0 mL of solution. andver: m Nach . .
Norma-Jean [14]

Answer:

1.23 M

Explanation:

Molarity of a substance , is the number of moles present in a liter of solution .

M = n / V

M = molarity  

V = volume of solution in liter ,

n = moles of solute ,

Moles is denoted by given mass divided by the molecular mass ,  

Hence ,  

n = w / m

n = moles ,  

w = given mass ,  

m = molecular mass .

From the question ,

w = given mass of NaCl = 7.2 g

As we know , the molecular mass of NaCl = 58.5 g/mol

Moles is calculated as -

n = w / m  =  7.2 g / 58.5 g/mol = 0.123 mol

Molarity is calculated as -

V = 100ml = 0.1 L            (since , 1 ml = 1/1000L )

M = n / V  =  0.123 mol / 0.1 L = 1.23 M

5 0
3 years ago
Examples for non metals​
nadezda [96]

Answer:

you can write plastic , paper , stone e.t.c

Explanation:

non metals means who are not being attracted by magnets

                                        or

which does not have good conductor of heat and electricity

          some others examples can be sulpher

4 0
2 years ago
Other questions:
  • A sample of helium (He) effuses 2.0 times faster than another gas. What is the molar mass of the other gas?
    7·1 answer
  • A banana can ripen sitting on the kitchen counter. Is this a physical or chemical property
    15·2 answers
  • Which of the following is true regarding musculoskeletal injuries in healthcare?
    5·2 answers
  • Which property of matter is conserved in chemical reactions and shown by balanced equations? mass volume density shape
    9·2 answers
  • How many neutrons does 85Rb have?
    5·1 answer
  • What are the roles of producers,consumers, and decomposers in an ecosystem?
    13·2 answers
  • Which substance is the oxidizing agent in this reaction? 2CuO+C→2Cu+CO2 Express your answer as a chemical formula.
    6·1 answer
  • If an electromagnetic wave has a frequency of 4.5 x 10^18 Hz, what is its wavelength? The speed of light is 3 x 108 m/s.
    7·1 answer
  • What must be balanced in order to have a balanced chemical equation?
    14·1 answer
  • Someone please HELPPPP
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!