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matrenka [14]
3 years ago
8

why HF (hydrogen fluoride) has higher boiling temperature than HCl (hydrogen chloride), even thought HF has lower molecular weig

ht?
Engineering
1 answer:
bekas [8.4K]3 years ago
5 0

Answer:

Boiling point of HF is higher as compared to HCl because of presence of hydrogen bonding in it.

Explanation:

In HF, intermolecular force of attraction is hydrogen bonding.

Hydrogen bonding is a type of electrostatic force of attraction existing between H atom and electronegative atom.

For a molecule to have hydrogen bonding, H atom must be bonded to electronegative atom, O, N and F.

Hydrogen bonding can be intermolecular and intramolecular.

So, in HF hydrogen bonding present.

In HCl, only van der Waals force exists. van der Waals forces are weak as compared to hydrogen bonding.

Because of presence of hydrogen bonding, HF molecules are held tightly and so requires more heat to boil.

Therefore, boiling point of HF is more as compared to HCl.

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P9.28 A large vacuum tank, held at 60 kPa absolute, sucks sea- level standard air through a converging nozzle whose throat diame
eimsori [14]

Answer:

a)  m=0.17kg/s

b)  Ma=0.89

Explanation:

From the question we are told that:

Pressure P=60kPa

Diameter d=3cm

Generally at sea level

T_0=288k\\\\\rho_0=1.225kg/m^3\\\\P_0=101350Pa\\\\r=1.4

Generally the Power series equation for Mach number is mathematically given by

\frac{p_0}{p}=(1+\frac{r-1}{2}Ma^2)^{\frac{r}{r-1}}

\frac{101350}{60*10^3}=(1+\frac{1.4-1}{2}Ma^2)^{\frac{1.4}{1.4-1}}

Ma=0.89

Therefore

Mass flow rate

\frac{\rho_0}{\rho}=(1+\frac{1.4-1}{2}(0.89)^2)^{\frac{1.4}{1.4-1}}

\frac{1.225}{\rho}=(1+\frac{1.4-1}{2}(0.89)^2)^{\frac{1.4}{1.4-1}}

\rho=0.848kg/m^3

Generally the equation for Velocity at throat is mathematically given by

V=Ma(r*T_0\sqrt{T_e})

Where

T_e=\frac{P_e}{R\rho}\\\\T_e=\frac{60*10^6}{288*0.842\rho}

T_e=248

Therefore

V=0.89(1.4*288\sqrt{248})\\\\V=284

Generally the equation for Mass flow rate is mathematically given by

m=\rho*A*V

m=0.84*\frac{\pi}{4}*3*10^{-2}*284

m=0.17kg/s

6 0
2 years ago
As you get older your muscles grow. True or False
xenn [34]

Answer:

True

Explanation:

This is a true fact because From the time you are born to around the time you turn 30, your muscles grow larger and stronger.

8 0
3 years ago
Read 2 more answers
Write down one metal or alloy that is best suited for each of the following applications:
777dan777 [17]

Answer:

Explanation:

a. Cast iron or Aluminium alloy are typically used. Aluminium is much lighter in weight and it can transfer heat better to the coolant. While Cast Iron is typically stronger and is thus still used by the manufacturers.

b. Copper can be used as a condensing heat exchanger for hot steam due to its optimal thermal properties and its ability to resist corrosion.

c. high-speed steel are perfect for producing drill bits because of its hardness and resistance to heat to an extent. Drill bits tend to produce heat as a result of the friction between it and the material to be drilled.

d. lead can be used as a container for strong acids because of its anti-corrosive properties

e.zinc and copper can be used as fuel in pyrotechnics mainly due to the fact that burn with refreshing colours. Aluminium can also be used.

f. Platinum is the metal that best suits this purpose because of its high melting point and resistivity to oxidation.

6 0
3 years ago
Joey has a car that uses the hand crank to open the windows. Joey is wondering where the energy comes from to open the windows.T
Sedaia [141]

Explanation:

Joey has a car that uses the hand crank to open the windows. Joey is wondering where the energy comes from to open the windows.The sunHuman-powered energy from JoeyThe hand crankThe moving car

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2 years ago
5. Which of the following is false about onStep?
katovenus [111]

The false statement about onStep is: B. The default number of steps per second is 30.

<h3>What is an onStep?</h3>

An onStep can be defined as a computerized telescope goto controller that is designed and developed to <u>animate shapes</u> while using it on a variety of mounting systems such as forks.

<h3>The characteristics of an onStep.</h3>

In Engineering, some of the characteristics that are associated with an onStep include the following:

  • The onStep function can be called without user input.
  • It can be used to animate shapes without user input.
  • It only runs a certain number of times.

In conclusion, the default number of steps per second for onStep isn't 30.

Read more on onStep here: brainly.com/question/25619349

7 0
2 years ago
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