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3 years ago

Why do the inner walls of a vacuum flask have a silver coating?

Chemistry

2 answers:

Liula [17]3 years ago

7 0

Answer:

to reduce heat loss by radiation.

Citrus2011 [14]3 years ago

5 0

Answer:

The inner walls of a vacuum flask have a silver coating to reduce heat loss by radiation.

Explanation:

The vacuum flask has an inner silver lining to prevent the transfer of heat by radiation. Radiation is a process where the emission or transformation of energy happens in the form of wave or the particles through the material medium.

Vacuum flask being working as thermal insulator helps in maintaining the substance its actual temperature for a long time. The silver lining acts as a reflector .It prevents the heat radiation to released out of the flask.

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2. Consider the reaction 2 Cg H18 (4) +250â (9) âº 16 co, (g) + 18 HâO(g) la How many moles of H20co) are produced, when |--16:1

Sladkaya [172]

Answer :

(a) The moles of water produced are 145.35 moles.

(b) The mass of oxygen needed are 3080.8 grams.

Solution for part (a) : Given,

Moles of $C_8H_{18}$ = 16.15 moles

First we have to calculate the moles of $H_2O$

The balanced chemical reaction is,

$2C_8H_{18}+25O_2\rightarrow 16CO_2+18H_2O$

From the balanced reaction we conclude that

As, 2 moles of $C_8H_{18}$ react to give 18 moles of $H_2O$

So, 16.15 moles of $C_8H_{18}$ react to give $\frac{16.15}{2}\times 18=145.35$ moles of $H_2O$

The moles of water produced are 145.35 moles.

Solution for part (b) : Given,

Mass of $C_8H_{18}$ = 878 g

Molar mass of $C_8H_{18}$ = 114 g/mole

Molar mass of $O_2$ = 32 g/mole

First we have to calculate the moles of $C_8H_{18}$ .

$\text{ Moles of }C_8H_{18}=\frac{\text{ Mass of }C_8H_{18}}{\text{ Molar mass of }C_8H_{18}}=\frac{878g}{114g/mole}=7.702moles$

Now we have to calculate the moles of $O_2$

The balanced chemical reaction is,

$2C_8H_{18}+25O_2\rightarrow 16CO_2+18H_2O$

From the balanced reaction we conclude that

As, 2 moles of $C_8H_{18}$ react with 25 moles of $O_2$

So, 7.702 moles of $C_8H_{18}$ react with $\frac{7.702}{2}\times 25=96.275$ moles of $O_2$

Now we have to calculate the mass of $O_2$ .

$\text{ Mass of }O_2=\text{ Moles of }O_2\times \text{ Molar mass of }O_2$

$\text{ Mass of }O_2=(96.275moles)\times (32g/mole)=3080.8g$

The mass of oxygen needed are 3080.8 grams.

6 0

3 years ago

13.8g element consist 4.6 ×10^22 atoms what is atomic mass of element?

Keith_Richards [23]

<h2>~Solution :-</h2>

Here, to find the atomic mass of element, we must;

We know that,

4.6 x $ \sf{10^{22}}$ atoms of an element weigh 13.8g.

Thus,

The atoms of $ \sf{ 6.02 \times 10^{13}}$ will weigh;

$= \sf{\frac{13.8 \times 6.02 \times {10}^{23} }{4.6 \times {10}^{22} } } \\$

$= \sf{180.6 \: g \: \: (molar \: mass)}$

Hence, the molar mass (atomic mass) will be 180.6 g.

8 0

2 years ago

Read 2 more answers

help please, How much water would you need to add to the 10 grams of sodium hydroxide to make 100 grams of the 10% solution?

jonny [76]

Answer:

Explanation:

gshhhshussussussjsuushhshjssuss

5 0

3 years ago

The Valence Electrons of an Atom of Which Element would feel a Greater Effective Nuclear Charge than the Valence?

kumpel [21]

The effective nuclear charge is an innate property of a specific element. It is the pull of force that an electron feels from the nucleus. It is related to the valence electron by the equation: Z* = Z-S, where Z* is the effective nuclear charge, Z is the atomic number and S is the shielding constant.

For the following elements in the choices, these are their values of Z*:

Aluminum - +12.591
Beryllium - +1.912
Hydrogen - +1
Carbon - +4

The effective nuclear charge of Boron is +3. Thus, the answers are Aluminum and Carbon.

5 0

3 years ago

What do hydroelectric plants use to turn a turbine when producing electrical energy?

oksian1 [2.3K]

A. water
the word hydro means water

7 0

3 years ago