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
lianna [129]
3 years ago
12

Fermium-253 is a radioactive isotope of fermium that has a half-life of 3.0 days. A scientist obtained a sample that contained 2

16 micrograms of fermium-253.
Complete the table to show how much fermium-253 should remain in the sample at the indicated times after the scientist obtained the sample.

Chemistry
2 answers:
Dahasolnce [82]3 years ago
5 0

Problem 2

You start out with 216 ugrams of Fermium - 253. After 3 days, you will have 1/2 as much. 108 ugrams is what you have.

Another 3 days goes by. You started with 108 ugrams. That gets cut in 1/2 again. Now you have 54 ugrams.

Finally another 3 days goes by. You started with 54 ugrams. you now have 1/2 as much which would be 27 ugrams

#days              Amount in micrograms

0                              216

3                               108

6                                54

9                                27

Problem One

You are using Nitrogen as your base example. The first thing you should do is fill in the table. Then you should try and make some rules. You need the rules in case the exam you are preparing for picks a different element to talk about these bond tendencies. In any event, it's handy to think this way.

<em><u>Table</u></em>

Bond               Energy Kj/Mol               Bond Length pico meters

N - N                 167                                                145

N=N                  418                                                125

N≡N                  942                                               110

<em><u>Rules</u></em>

As the number of bonds INCREASES, the energy contained in the bond goes UP

As the number of bonds INCREASES, the length of the bond goes DOWN.

Lera25 [3.4K]3 years ago
5 0

1. <em>Radioactive decay </em>

The <em>half-life</em> of Fm-198 (3.0 days) is the time it takes for half the Fm to decay.  

After one half-life, half (50 %) of the original amount will remain.

After a second half-life, half of that amount (25 %) will remain, and so on.

We can construct a table as follows:

 No. of                   Fraction         Amount

<u>half-lives</u>  <em><u>t</u></em><u>/days</u>  <u>remaining</u>   <u>remaining/µg</u>

       1          3.0             ½                  216

       2         6.0             ¼                  108

       3         9.0             ⅛                    54

2. <em>Bond length and bond energy </em>

The <em>bond order</em> of a bond is the number of bonding electrons between the two nuclei.

As the <em>number of bonding electrons increases</em>, the nuclei are pulled more tightly together (the <em>bond energy increases</em>) and the <em>bond length decreases</em>.

We can construct a table as follows:

<u>Bond</u>  <u>Bond energy/kJ·mol⁻¹</u><u> </u>  <u>Bond length/pm </u>

N-N                 167                                 145

N=N                 418                                 125

N≡N                 942                                 110

You might be interested in
Help me with this hw (homework)
Elan Coil [88]

Answer:

maison travaille

Explanation:

maison travaille

3 0
2 years ago
The following balanced equation describes the reduction of iron(III) oxide to molten iron within a blast furnace: Fe2O3(s) + 3CO
Irina-Kira [14]

Answer:

Amount of excess Carbon (ii) oxide left over = 23.75 g

Explanation:

Equation of the reaction: Fe₂O₃ + 3CO ----> 2Fe + 3CO₂

Molar mass of Fe₂O₃ = 160 g/mol;

Molar mass of Carbon (ii) oxide = 28 g/mol

From the equation of reaction, 1 mole of Fe₂O₃ reacts with 3 moles of carbon (ii) oxide; i.e. 160 g of iron (iii) oxide reacts with 84 g (3 * 28 g)  of carbon (ii) oxide

450 g of Fe₂O₃ will react with 450 * 84/180) g of carbon (ii) oxide = 236..25 g of carbon (ii) oxide

Therefore the excess reactant is carbon (ii) oxide.

Amount of excess Carbon (ii) oxide left over = 260 - 236.25

Amount of excess Carbon (ii) oxide left over = 23.75 g

5 0
2 years ago
The following compound has been found effective in treating pain and inflammation (J. Med Chem. 2007, 4222). Which sequence corr
love history [14]
<h3><u>Full Question:</u></h3>

The following compound has been found effective in treating pain and inflammation (J. Med. Chem. 2007, 4222). Which sequence correctly ranks each carbonyl group in order of increasing reactivity toward nucleophilic addition?

A) 1 < 2 < 3

B) 2 < 3 < 1

C) 3 < 1 < 2

D) 1 < 3 < 2

<h3><u>Answer: </u></h3>

The rate of nucleophilic attack of carbonyl compounds is 2<3 <1.

Option B

<h3><u>Explanation. </u></h3>

Nucleophilic attack is explained as the attack of an electron rich radical to a carbonyl compound like aldehyde or a ketone. A nucleophile has a high electron density, so it searches for a electropositive atom where it can donate a portion of its electron density and become stable.

A carbonyl compound is a sp^2 hybridized carbon atom with a double bonded oxygen atom in it. The oxygen atom pulls a huge portion of electron density from carbon being very electropositive.

In a ketone, there are two factors that make it less likely to undergo a nucleophilic attack than aldehyde. Firstly, the steric hindrance of two carbon groups being attached with the carbonyl carbon makes it harder for the nucleophile to approach. Secondly, the electron push by the carbon groups attached makes the carbonyl carbon a bit less electropositive than the aldehyde one. So aldehydes are more reactive towards a nucleophilic addition reaction.

7 0
3 years ago
PLEASE HELP WITH TRUE OR FALSE QUESTIONS!!!!!
Elodia [21]
First one is true second one is False
3 0
2 years ago
Consider the reaction NOBr(g) =&gt; NO(g) + 1/2 Br2(g). A plot of 1/[NOBr] vs time give a straight line with a slope of 2.00 M-1
timama [110]

Answer:

Thus, the order of the reaction is 2.

The rate constant of the graph which is :- 2.00 M⁻¹s⁻¹

Explanation:

The kinetics of a reaction can be known graphically by plotting the concentration vs time experimental data on a sheet of graph.

The concentration vs time graph of zero order reactions is linear with negative slope.

The concentration vs time graph for a first order reactions is a exponential curve.  For first order kinetics the graph between the natural logarithm of the concentration vs time comes out to be a straight graph with negative slope.

The concentration vs time graph for a second order reaction is a hyberbolic curve. Also, for second order kinetics the graph between the reciprocal of the concentration vs time comes out to be a straight graph with positive slope.

Considering the question,

A plot of 1/[NOBr] vs time give a straight line with a slope of 2.00 M⁻¹s⁻¹.

<u>Thus, the order of the reaction is 2.</u>

<u>Also, slope is the rate constant of the graph which is :- 2.00 M⁻¹s⁻¹</u>

5 0
3 years ago
Other questions:
  • A mineral sample is obtained from a region of the country that has high arsenic contamination. An elemental analysis yields the
    8·1 answer
  • What was the purpose of putting distilled water in the blank cuvette? if your unknown used ethanol as the base solvent, what wou
    15·1 answer
  • How are gems different from regular minerals? Gems are softer than regular minerals. Regular minerals are more beautiful than ge
    8·2 answers
  • Oxygen gas can be prepared by heating potassium chlorate according to the following equation: 2KClO3(s)2KCl(s) + 3O2(g) The prod
    14·1 answer
  • For the balanced equationLaTeX: 2Li\left(s\right)\:+\:2H_2O\left(l\right)\:\longrightarrow\:2LiOH\left(aq\right)\:+\:H_2\left(g\
    12·1 answer
  • What is the relationship between wind and ocean waves
    13·1 answer
  • BaCl2 (aq) + AgNO3 (aq) →
    8·2 answers
  • A weight of 8.7 N is attached to a spring that has a spring constant of 190 N/m. How much will the spring stretch?
    9·1 answer
  • In Philip’s French class, the students are learning how to pronounce closed vowels and open vowels. The students are most likely
    10·2 answers
  • Which element in Group 17 is the most active nonmetal? (1) Br (2) I (3) Cl (4) F
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!