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geniusboy [140]
4 years ago
13

How many neutrons do (k) potassium-39 and potassium-40 have, respectively?

Chemistry
1 answer:
Maurinko [17]4 years ago
7 0
Potassium’s atomic number in periodic table is 19, Potassium can only have a mass numbers of 41, 40 and 39. Potassium 39, 40, and 41 are all different isotopes of the element potassium. Each of the isotopes has 19 electrons and 19 protons but the number of neutrons vary. So, in your question Potassium-39 has twenty (20) neutrons, and potassium-40 has 21 neutrons.
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Question 15 need this answered asap (chemistry)
Tcecarenko [31]

Answer:

80.7 L

Explanation:

PV = nRT

P = 1520 mmHg = 2 atm

n = 5 mol

R = 0.08206 (L * atm)/(mol * K)

T = 393.15 K

2 (V) = 5 (0.08206) (393.15)

V ≈ 80.7 L

8 0
3 years ago
Consider the following Reaction.
jeyben [28]

Hey there!:

Molar mass of Mg(OH)2 = 58.33 g/mol


number of moles Mg(OH)2 :

moles of Mg(OH)2 = 30.6 / 58.33 =>  0.5246 moles

Molar mass of H3PO4 =  97.99 g/mol

number of moles H3PO4:

moles of Mg(OH)2 = 63.6 / 97.99 => 0.649 moles

Balanced chemical equation is:


3 Mg(OH)2 + 2 H3PO4 --->  Mg3(PO4)2 + 6 H2O


3 mol of Mg(OH)2 reacts with 2 mol of H3PO4  ,for 0.5246 moles of Mg(OH)2, 0.3498 moles of H3PO4 is required , but we have 0.649 moles of H3PO4, so, Mg(OH)2 is limiting reagent !

Now , we will use Mg(OH)2 in further calculation  .

Molar mass of Mg3(PO4)2 = 262.87 g/mol

According to balanced equation  :

mol of Mg3(PO4)2 formed = (1/3)* moles of Mg(OH)2


= (1/3)*0.5246


= 0.1749 moles of Mg3(PO4)2

use :

mass of Mg3(PO4)2 = number of mol * molar mass


= 0.1749 *  262.87

= 46 g of Mg3(PO4)2

Therefore:

% yield = actual mass * 100 / theoretical mass

% = 34.7 * 100 / 46

% = 3470 / 46

= 75.5%


Hope that helps!




3 0
3 years ago
In what order did mendeleev arrange the elements in his periodic table?
irina1246 [14]
He realized that the physical and chemical properties of elements<span> were related to their atomic mass in a '</span>periodic<span>' way, and </span>arranged<span> them so that groups of </span>elements<span> with similar properties fell into vertical columns in </span>his table<span>.
</span><span>
</span>
3 0
3 years ago
Which of the following BEST describes a way in which water moves in the water cycle?
____ [38]

Answer: Its A or D                                                        

wish i had an actual answer sorry..  

6 0
3 years ago
Read 2 more answers
while ionic compounds in the solid state do not conduct electricity, when they are melted, electric current
evablogger [386]

Answer:

Explanation:

Ionic (or electrovalent) compounds conduct electricity when there they are in the aqueous state/solution because the charges of ions of these compounds are what carry the electric charges in the aqueous solution as a result of free movement within the aqueous solution which they do not "have" when in there solid state (where they have a highly restricted movement/compacted structure).

3 0
3 years ago
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