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
Cerrena [4.2K]
3 years ago
7

3.) A 208 g sample of sodium-24 decays to 13.0 g of sodium-24 within 60.0 hours.

Chemistry
1 answer:
Ulleksa [173]3 years ago
3 0

Answer:

Half life = 12 hrs

Explanation:

Given data:

Total amount of sample = 208 g

Amount left after 60 hr = 13.0 g

Half life = ?

Solution:

Step one:

amount             half life

208 g                    time 0

208/2                   1 half life

104/2                    2 half life

52/2                     3 half life

26/2                     4 half life

13                         5 half life

Step 2:

half life = elapsed time/ total half life when 13 g is left

Half life = 60 hrs/ 5

Half life = 12 hrs

You might be interested in
You wish to prepare 100 mL of 0.600 M HCl from concentrated HCl (12.85 M). You are provided with a 100 mL volumetric flask and a
Soloha48 [4]

Answer:

Because we need to dispense 4.7 mL, the volume reading in the pipet is the 5.3 mL line.

Explanation:

First we use C₁V₁=C₂V₂ in order to <u>calculate the required volume of concentrated HCl</u> (V₁):

12.85 M * V₁ = 0.600 M * 100 mL

V₁ = 4.7 mL

<u>So we need to dispense 4.7 mL of the concentrated HCl solution</u>. The mark in the pipet that would contain that volume would be 10.0 - 4.7 = 5.3 mL

8 0
3 years ago
PLEASE HELP ME :( It’s urgent!!!!!
MrRa [10]

Answer:

C and D

Explanation:

In the first table, both element particles have more electrons than protons which is unusual and indicates they have a negative charge. Furthermore both numbers add up to full electron shells (2,8 and 2,8,8) meaning they are ions (charged particles formed to gain full valence shells and become stable), so it is C for the first question, negative ions.

As for the second one, isotopes like versions of the same element except with different numbers of neutrons, so they are still the same element but have different mass. As shown here the numbers indicate the number of neutrons therefore it is D, 3 more neutrons and no more electrons.

Hope this helped!

5 0
3 years ago
2. force → the rate at which an object changes position; distance divided by time
yaroslaw [1]

Answer:

2. True

3. True

4. False

Explanation:

4 0
3 years ago
Create a chart that compares physical and chemical properties. Give two examples for each type of property
Zinaida [17]

<em>Answer:</em>

<em>Chemical properties:</em>

Those properties which change the chemical nature of matter.

<em>Example:</em>  

  •       Heat of combustion
  •       Enthalpy of formation

<em>Physical properties:</em>

Those properties which do not change the chemical nature of matter.

<em>Example</em>

  • B.P
  • M.P
  • F.P

<em>Differences between chemical and physical properties:</em>

       Chemical properties                                       Physical properties

1. Observed after the change bringing           1. Observed with out being

the change                                                            change

2. These changes the molecules                    2. only change physical state

3. Chemical identity changes                          3.Chemical identity not changes

4. Structure of material changes                     4.Structure of material not change            

5. Chemical reaction is needed                       5. No need of Chemical reaction

6. depend on composition                           6. Does not depend on composition

3 0
3 years ago
Plz help asap
LenaWriter [7]
The right answer is A
4 0
3 years ago
Other questions:
  • An average copper penny minted in the 1960s contained about 3.000 g of copper. how much chalcopyrite had be mined to produce 100
    6·2 answers
  • All organisms use oxidation-reduction reactions to harness energy, and this newly harvested energy is used to produce atp. oxida
    12·1 answer
  • Identify the two principal products of the reaction between ammonia and ethyl propionate
    6·1 answer
  • Which group has different numbers of valence electrons
    7·1 answer
  • Atomic mass of an element depends upon what
    7·2 answers
  • Why do some compounds form double or triple bonds?
    13·2 answers
  • Identify the outer electron configurations for the (a) alkali metals, (b) alkaline earth metals, (c) halogens, (d) noble gases.
    10·1 answer
  • How and why do we see colors?
    11·1 answer
  • What is the F-Xe angle in the molecule - F; Xe * F_{2} (Xe has three lone pairs of electrons )?
    10·1 answer
  • The pressure on 20 mL of a gas at constant temperature is changed from 4.0 atm to 2.0 atm. What is the new volume?
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!