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yanalaym [24]
3 years ago
15

Which of the following elements is a nonmetal? a. selenium (Se) b. yttrium (Y) c. barium (Ba) d. calcium (Ca) e. All of these ar

e metals.
Chemistry
2 answers:
Fynjy0 [20]3 years ago
8 0

Answer:

a. Selenium

Explanation:

Selenium is a non metal but though rarely, it is considered to be a metalloid.

(Metalloids are elements intermediate between metals and nonmetals and are known to have partly metallic and partly non metallic properties.)

Selenium is in group 16 of the periodic table below sulphur and has average properties of the group elements above and below it in the periodic table..  

san4es73 [151]3 years ago
3 0

<u>Answer:</u>

The correct answer option is a. Selenium (Se).

<u>Explanation:</u>

From the given answer options, Selenium (Se) is the only element which is a non metal.

It has the atomic number 34 with atomic weight 78.96. It is a member of the sulfur group of the non metallic elements and falls in period 4 of the Periodic table.

Selenium has non metallic properties which are intermediate between the elements that lie above and below it in the Periodic table.

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Question 2 (1 point)
Zigmanuir [339]

Answer: they are both at the same concentration

Explanation: You will know that the amount of solvent in and around the cell will be equivalent when they have the same amount of concentration. The answer to the question is they are both at the same concentration.

7 0
3 years ago
According to the law of conservation of mass, the total mass of the reacting substances is
atroni [7]

Answer:

I would say the last one because mass is not created nor destroyed.

Explanation:

7 0
2 years ago
Pls help I’ll mark brainliest pls pls pls
katovenus [111]
The tea was no longer hot or (brewed) so the 5th didn’t dissolve like the others because the tea was hot or warm enough anymore it cooled down. So the sugar won’t dissolve no more.
7 0
3 years ago
Read 2 more answers
A 5.0 L sample of gas at 300. K is heated to 600. K. What will the new volume of the gas be?
Ainat [17]

Answer:

V_2=10L

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the required new volume by using the Charles' law as a directly proportional relationship between temperature and volume:

\frac{V_2}{T_2} =\frac{V_1}{T_1}

In such a way, we solve for V2 and plug in V1, T1 and T2 to obtain:

V_2=\frac{V_1T_2}{T_1}\\\\V_2=\frac{5.0L*600K}{300K}\\\\V_2=10L

Regards!

4 0
3 years ago
Can anyone help me on this please?
Bad White [126]
This question is testing to see how well you understand the "half-life" of radioactive elements, and how well you can manipulate and dance around them.  This is not an easy question.

The idea is that the "half-life" is a certain amount of time.  It's the time it takes for 'half' of the atoms in any sample of that particular unstable element to 'decay' ... their nuclei die, fall apart, and turn into nuclei of other elements.

Look over the table.  There are 4,500 atoms of this radioactive substance when the time is 12,000 seconds, and there are 2,250 atoms of it left when the time is ' y ' seconds.  Gosh ... 2,250 is exactly half of 4,500 !  So the length of time from 12,000 seconds until ' y ' is the half life of this substance !  But how can we find the length of the half-life ? ? ?

Maybe we can figure it out from other information in the table !

Here's what I found:

Do you see the time when there were 3,600 atoms of it ? 
That's 20,000 seconds.

... After one half-life, there were 1,800 atoms left.
... After another half-life, there were 900 atoms left.
... After another half-life, there were 450 atoms left. 

==>  450 is in the table !  That's at 95,000 seconds.

So the length of time from 20,000 seconds until 95,000 seconds
is three half-lifes.

The length of time is (95,000 - 20,000) = 75,000 sec

                                     3 half lifes = 75,000 sec

Divide each side by 3 :   1 half life = 25,000 seconds

There it is !  THAT's the number we need.  We can answer the question now.

==> 2,250 atoms is half of 4,500 atoms.

==> ' y ' is one half-life later than 12,000 seconds

==> ' y ' = 12,000 + 25,000

         y   = 37,000 seconds  .

Check: 
Look how nicely 37,000sec fits in between 20,000 and 60,000 in the table.

As I said earlier, this is not the simplest half-life problem I've seen.
You really have to know what you're doing on this one.  You can't
bluff through it.


7 0
3 years ago
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