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2 years ago

14

Which of the following symbols would be included in the noble gas notation for an element that had valence electrons in the 5s s

ubshell? Ar Kr Xe Rn

2 answers:

alexandr1967 [171]2 years ago

7 0

Answer: C. (Xe)

Explanation:

yulyashka [42]2 years ago

7 0

Answer:

c

Explanation:

on edge

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Briefly explain why the bulk temperature of the water remains low (at room temperature)

elena55 [62]

If the humidity of the room is low, the water that contacts the air directly could evaporate and takes some energy from the bulk thus decreasing its temperature steadily. This allows the water to have a lower temperature.

4 0

3 years ago

3. The alcohol in "gasohol" burns according to the following equation. C2H6O + 3 O2 --------> 2 CO2 + 3 H2O (a) If 25 moles o

Vanyuwa [196]

For all question, all you need to use is the mole-mole ratio.

a) 25 moles C2H6O (3 moles O2/ 1 mol C2H6O)= 75 moles O2

b) 30 moles O2 (1 moles C2H6O/ 3 moles O2)= 10 moles C2H6O

c) 23 moles CO2 (3 moles O2/ 2 moles CO2) = 34.5 moles O2

d) 41 moles H2O ( 1 moles C2H6O/ 3 moles H2O= 13.7 moles C2H6O

7 0

3 years ago

You have 0.21 moles of Al how many atoms do you have

ZanzabumX [31]

Number of atoms : 1.26 x 10²³

<h3>Further explanation </h3>

The mole is the number of particles(molecules, atoms, ions) contained in a substance

1 mol = 6.02.10²³ particles

Can be formulated

N=n x No

N = number of particles

n = mol

No = Avogadro's = 6.02.10²³

0.21 moles of Al, so n = 0.21

Number of atoms :

$\tt N=0.21\times 6.02\times 10^{23}\\\\N=1.26\times 10^{23}$

8 0

2 years ago

If 8.50 g of phosphorus reacts with hydrogen gas at 2.00 atm in a 10.0-L container at 298 K, calculate the moles of PH3 produced

ahrayia [7]

Answer:

The moles of PH₃ produced are 0.2742 and the total number of moles of gas present at the end of the reaction is 0.6809.

Explanation:

Phosphorus reacts with H₂ according to the balanced equation:

P₄ (s) + 6 H₂ (g) ⇒ 4 PH₃ (g)

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of each compound participate in the reaction:

P₄: 1 mole
H₂: 6 moles
PH₃:4 moles

Being the molar mass of the compounds:

P₄: 124 g/mole
H₂: 2 g/mole
PH₃: 34 g/mole

The following mass amounts of each compound participate in the reaction:

P₄: 1 mole* 124 g/mole= 124 g
H₂: 6 mole* 2 g/mole= 12 g
PH₃: 4 moles* 34 g/mole= 136 g

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P * V = n * R * T

In this case you know:

P= 2 atm
V= 10 L
n= ?
R= 0.082 $\frac{atm*L}{mol*K}$
T= 298 K

Replacing:

2 atm*10 L= n*0.082 $\frac{atm*L}{mol*K}$ *298 K

and solving you get:

$n=\frac{2 atm*10 L}{0.082\frac{atm*L}{mol*K}*298 K }$

n=0.818 moles

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, you can use a simple rule of three as follows: if 6 moles of H₂ react with 124 g of P₄, 0.818 moles of H₂ with how much mass of P₄ will it react?

$mass of P_{4}=\frac{0.818 moles of H_{2}*124 grams of P_{4}}{6 moles of H_{2}}$

mass of P₄= 16.90 grams

But 16.90 grams of P₄ are not available, 8.50 grams are available. Since you have less mass than you need to react with 0.818 moles of H₂, phosphorus P₄ will be the limiting reagent.

Then you can apply the following rules of three:

If 124 grams of P₄ produce 4 moles of PH₃, 8.50 grams of P₄, how many moles do they produce?

$moles of PH_{3} =\frac{8.5 grams of P_{4}*4 moles of PH_{3} }{124grams of P_{4}}$

moles of PH₃=0.2742

If 124 grams of P₄ react with 6 moles of H₂, 8.50 grams of P₄ with how many moles of H₂ do they react?

$moles of H_{2} =\frac{8.5 grams of P_{4}*6 moles of H_{2} }{124grams of P_{4}}$

moles of H₂= 0.4113

If you have 0.818 moles of H₂, the number of moles of gas H₂ present at the end of the reaction is calculated as:

0.818 - 0.4113= 0.4067

Then the total number of moles of gas present at the end of the reaction will be the sum of the moles of PH₃ gas and H₂ gas that did not react:

0.2742 + 0.4067= 0.6809

Finally, <u><em>the moles of PH₃ produced are 0.2742 and the total number of moles of gas present at the end of the reaction is 0.6809.</em></u>

5 0

2 years ago

Which reaction represents the process of neutralization? Mg(s)+2HCl(aq) MgCl 2 (aq)+H 2 (g) HCl(aq)+KOH(aq) KCl(aq)+H 2 O(l) C.

Alex

Answer:

HCl(aq) + KOH(aq) --> KCl(aq) + H2O(l)

Explanation:

A neutralization reaction is the process between an acid and a base (there are a number of different ways to define acids and bases). An acid is a compound, which dissolves in water by releasing H+ ions, and a base is a compound, which dissolves in water by releasing OH- ions (by Arrhenius' definition, the simplest one). In this case, the neutralization reaction is the process between HCl (hydrochloric acid) - an acid, and KOH (potassium hydroxide) - a base.

7 0

3 years ago