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Sergio039 [100]
4 years ago
5

IM GIVING 95 POINTS THIS NEEDS TO BE CORRECT!!!!!!

Chemistry
2 answers:
olya-2409 [2.1K]4 years ago
7 0
Technically there are 118 but C is the closest answer... :)
Colt1911 [192]4 years ago
6 0
C. 115 is your best answer

There are 118 elements in the Periodic Table

hope this helps
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Solid at room temperature. They are used in making computers and electronic devices. Have properties of both metals and nonmetal
larisa86 [58]

Answers:  metaloids

Explanation:

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Ammonia (NH3) clouds are present around some planets. Calculate the number of grams of ammonia produced by the reaction of 5.4 g
Komok [63]

Answer:

30.4 g. NH3

Explanation:

This problem tells us that the hydrogen (H2) is the limiting reactant, as there is "an excess of nitrogen." Using stoichiometry (the relationship between the various species of the equation), we can see that for every 3 moles of H2 consumed, 2 moles of NH3 are produced.

But before we can use that relationship to find the number of grams of ammonia produced, we need to convert the given grams of hydrogen into moles:

5.4 g x [1 mol H2/(1.008x2 g.)] = 2.67857 mol H2 (not using significant figures yet; want to be as accurate as possible)

Now, we can use the relationship between H2 and NH3.

2.67857 mol H2 x (2 mol NH3/3 mol H2) = 1.7857 mol NH3

Now, we have the number of moles of ammonia produced, but the answer asks us for grams. Use the molar mass of ammonia to convert.

1.7857 mol NH3 x 17.034 g. NH3/mol NH3 = 30.4 g. NH3 (used a default # of 3 sig figs)

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3 years ago
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How do you know when a phase change happens?
VladimirAG [237]

Answer:

phase for what?

Explanation:

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A compound is found to contain 38.65 % carbon, 16.25 % hydrogen, and 45.09 % nitrogen by mass. what is the empirical formula for
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The molar mass of carbon is 12, hydrogen is 1, and nitrogen is 14, hence the ratio are:

 

C = 38.65 / 12 = 3.22

H = 16.25 / 1 = 16.25

N = 45.09 / 14 = 3.22

 

Divide the three by the lowest ratio which is 3.22:

 

C = 3.22 / 3.22 = 1

H = 16.25 / 3.22 = 5

N = 3.22 / 3.22 = 1

 

So the empirical formula is:

CHN

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A cylinder is filled with 2.00 moles of nitrogen, 3.00 moles of argon, and 5.00 moles of helium.
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PRACTICE MULTIPLE CHOICE QUESTIONS FROM UNIT 10

1.) A cylinder is filled with 2.00 moles of nitrogen, 3.00 moles of argon, and 5.00 moles of helium. If

the gas mixture is at STP, what is the partial pressure of the argon?

(A) 152 torr (B) 228 torr (C) 380. torr (D) 760. torr

2.) Compared to the average kinetic energy of 1 mole of water at 0 oC, the average kinetic energy

of 1 mole of water at 298 K is

(A) the same, and the number of molecules is the same

(B) the same, but the number of molecules is greater

(C) greater, and the number of molecules is greater

(D) greater, but the number of molecules is the same

3.) If the pressure on a given mass of gas in a closed system is increased and the temperature

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5.) At a temperature of 273 K, a 400. milliliter gas sample has a pressure of 760. millimeters of

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(A) 100 K (B) 188 K (C) 273 K (D) 546 K

Get the answers to these questions

Back to the Unit 10 Old Tests Page

Back to the Unit 10 Page

Back to the Main Page

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3 years ago
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