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Harrizon [31]
3 years ago
13

The half-life of cesium-137 is 30 years. Suppose we have a 200-mg sample. (a) Find the mass that remains after t years.

Chemistry
1 answer:
scZoUnD [109]3 years ago
5 0

Given:

Half life(t^ 1/2) :30 years

A0( initial mass of the substance): 200 mg.

Now we know that

A= A0/ [2 ^ (t/√t)]

Where A is the mass that remains after t years.

A0 is the initial mass

t is the time

t^1/2 is the half life

Substituting the given values in the above equation we get

A= [200/ 2^(t/30) ] mg


Thus the mass remaining after t years is [200/ 2^(t/30) ] mg

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Which of the following atoms forms an ionic bond with a sulfur atom? (Points : 3)
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Ionic bonds are formed when there is complete transfer of valence electrons between two atoms.

Electronegativity tells the trend of an atom to atract electrons.

You should search for the complete set of rules that indicate whether an ionic or covalent bond happens.

There are two relevant rules to state if whether an ionic bond will happen:

- When the difference of electronegativities between the two atoms is greater than 2.0, then the bond is ionic.

- When the difference is between 1.6 and 2.0, the bond is ionic if one of the elements is a metal.

You need to list the electronegativities of the five elements (there are tables with this information)

Element  electronegativity

Cu:    1.9
H:      2.2
Cl      3.16
I:        2.66
S:      2.58

Differences:

Cu / S: 2.58 - 1.9 = 0.68
H / S: 2.58 - 2.2 = 0.38
Cl / S: 3.16 - 2.58 =0.58
I / S: 2.66 -  2.58 = 0.08

 Those differences are too low to consider that the bond is ionic.

Then the answer is that none of those atoms forms an ionic bond with sulfur.
8 0
3 years ago
Read 2 more answers
When data does not support your hypothesis in an experiment, you must revise what
Blababa [14]

state what the lab is about, that is, what scientific concept (theory, principle, procedure, etc.) you are supposed to be learning about by doing the lab. You should do this briefly, in a sentence or two. If you are having trouble writing the opening sentence of the report, you can try something like: "This laboratory experiment focuses on X…"; "This lab is designed to help students learn about, observe, or investigate, X…." Or begin with a definition of the scientific concept: "X is a theory that…."

2. give the necessary background for the scientific concept by telling what you know about it (the main references you can use are the lab manual, the textbook, lecture notes, and other sources recommended by the lab manual or lab instructor; in more advanced labs you may also be expected to cite the findings of previous scientific studies related to the lab). In relatively simple labs you can do this in a paragraph following the initial statement of the scientific concept of the lab. But in more complex labs, the background may require more paragraphs.

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3 years ago
Question 6 (1 point)
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Answer:

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8 0
3 years ago
A chemical reaction produced 10.1 cm3 of nitrogen gas at 23 °C and 746 mmHg. What is the volume of this gas if the temperature a
adell [148]

Answer:

volume of gas = 9.1436cm³

Explanation:

We will only temperature from °C to K since the conversion is done by the addition of 273 to the Celsius value.

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A good scientific research or experiment should have an element of reproducibility. In order words, the claim made in published scientific research should be reproducible by any other scientist that decides to replicate the research. <u>Tara repeated Victor's experiment in order to check its reproducibility and when she could not reproduce the results, she had to tell Victor to conduct the experiment again before deciding to publish it.</u>

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