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4 years ago

Which group on the periodic table is naturally stable (unreactive) due to the fact that the atoms' valence shells are full?

1 answer:

7 0

Group 18: noble gases

This is a matter of memorizing the groups of the periodic table. The rightmost column is group 18 which is the noble gases: Helium, Neon, Argon, Krypton, Xenon, Radon. In general, the noble gases don't make chemical compounds. Although there have been some compounds made with the heavier noble gases (Krypton, Xenon, Radon).

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Which two mantle hot spots are located at mid-ocean ridges?

Darya [45]

Answer:

This region of thick, hot crust and mantle extends 1,300 kilometers north and south of the Iceland hotspot and some 1,000 kilometers north and south of the Azores hotspot. Together, the two hotspots appear to be feeding a huge supply of magma to nearly the entire northern segment of the Mid-Atlantic Ridge.

Explanation:

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7 0

3 years ago

If a gas occupies 4600 mL at 0.9 atm and 195°C, what is the new volume in ml

Bumek [7]

Answer:

The new volume is 2415 mL

Explanation:

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases.

Boyle's law says that the volume occupied by a given gas mass at constant temperature is inversely proportional to the pressure and is expressed mathematically as:

P * V = k

Charles's law is a law that says that when the amount of gas and pressure are kept constant, the ratio between volume and temperature will always have the same value:

$\frac{V}{T} =k$

Gay-Lussac's law indicates that when there is a constant volume, as the temperature increases, the gas pressure increases. And when the temperature is decreased, the gas pressure decreases. This can be expressed mathematically in the following way:

$\frac{P}{T} =k$

Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:

$\frac{P*V}{T} =k$

Having two different states, an initial state and an final state, it is true:

$\frac{P1*V1}{T1} =\frac{P2*V2}{T2}$

In this case:

P1= 0.9 atm
V1=4,600 mL= 4.6 L (being 1 L=1,000 mL)
T1= 195 °C= 468 °K (being 0°C=273°K)

The final state 2 is in STP conditions:

P2= 1 atm
V2= ?
T2= 0°C= 273 °K

Replacing:

$\frac{0.9 atm*4.6L}{468K} =\frac{1 atm*V2}{273K}$

Solving:

$V2=\frac{0.9 atm*4.6L}{468K}*\frac{273K}{1 atm}$

V2= 2.415 L =2,415 mL

The new volume is 2415 mL

6 0

3 years ago

Decane (C10H22) is used in diesel. The combustion for decane follows the equation: 2 C10H22 + 31 O2 à 20 CO2 + 22 H2O. Calculate

creativ13 [48]

The mass of water produced is 792 grams by the combustion of 568 grams of decane.

Given:

Combustion of 568 grams of decane with 2979 grams of oxygen.

$2 C_{10}H_{22 }+ 31 O_2 \rightarrow 20 CO_2 + 22 H_2O$

To find:

The mass of water produced by combustion of 568 grams of decane.

Solution:

Mass of decane = 568 g

Moles of decane :

= $\frac{568 g}{142 g/mol}=4 mol$

Mass of oxygen gas = 2976 g

Moles of oxygen gas:

= $\frac{2976 g}{32 g/mol}=93 mol$

$2 C_{10}H_{22 }+ 31 O_2 \rightarrow 20 CO_2 + 22 H_2O$

According to reaction, 2 moles of decane reacts with 31 moles of oxygen, then 4 moles of decane will react with:

$=\frac{31}{2}\times 4mol=62\text{ mol of}O_2$

But according to the question, we have 93.0 moles of oxygen gas which is more than 62 moles of oxygen gas.

So, this means that oxygen gas is present in an excessive amount. Which simply means:

Oxygen gas is an excessive reagent.
Decane is a limiting reagent.
Decane being limiting reagent will be responsible for the amount of water produced after the reaction.

According to reaction, 22 moles of water is produced from 2 moles of decane, then 4 moles of decane will produce:

$=\frac{22}{2}\times 4mol=44\text{mol of }H_2O$

Mass of 44 moles of water ;

$=44mol\times 18g/mol=792g$

792 grams of water is produced by the combustion of 568 grams of decane.

Learn more about limiting reagent and excessive reagent here:

brainly.com/question/14225536?referrer=searchResults

brainly.com/question/7144022?referrer=searchResults

3 0

3 years ago

Which of the following an inorganic compound?

oksano4ka [1.4K]

An organic compound is one which consists of a chain of carbon atoms with other atoms bonded to the chain.

Pentane has 5 carbon atoms with surrounding hydrogens.
glucose is a chain of 6 carbon atoms
butane is similar to pentane

water has no carbon atoms, and the central atom is oxygen ---> therefore it is inorganic!

8 0

4 years ago

Which best describes the effect of J. J. Thomson’s discovery?

vlabodo [156]

The correct answer for the question that is being presented above is this one: "A. The accepted model of the atom was changed." J J Thomson discovered the electrons and performed experiment using the cathode ray tube
Here are the following choices:
A. The accepted model of the atom was changed.
B. The accepted model of the atom was supported.
C. Cathode ray tubes were no longer used in experiments due to poor results.
D. Cathode ray tubes became the only instrument of use in the study of atoms

8 0

3 years ago