1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Brrunno [24]
3 years ago
5

How much ethylene glycol (C2H6O2, the major component of antifreeze) must be added to 1 L of water to keep it from freezing at -

15 oC? Kf = 1.86 oC/m.
Physics
1 answer:
irga5000 [103]3 years ago
5 0

Answer:

6.97 grams

Explanation:

T = m × Kf

m ( molality) = T/Kf

T = -15°C = -15+273 = 258 K

Kf = 1.86°C/m = 1.86°C/m × 1K/1°C = 1.86 K/m

Molality = 258/1.86 = 138.71 mol/kg

Mass of ethylene glycol = molality×mass of water in kilograms×molecular weight of ethylene glycol

1 mole of water = 22.4 L

1 L of water = 1/22.4 = 0.045 mol

Mass of water = 0.045 mol × 18g/mol = 0.81 g = 0.81/1000 = 8.1×10^-4 kg

Mass of ethylene glycol = 138.71×8.1×10^-4×62 = 6.97 grams

You might be interested in
A block of 250-mm length and 54 × 40-mm cross section is to support a centric compressive load P. The material to be used is a b
musickatia [10]

Answer:

P = 17.28*10⁶ N

Explanation:

Given

L = 250 mm = 0.25 m

a = 0.54 m

b = 0.40 m

E = 95 GPa = 95*10⁹ Pa

σmax = 80 MPa = 80*10⁶ Pa

ΔL = 0.12%*L = 0.0012*0.25 m = 3*10⁻⁴ m

We get A as follows:

A = a*b = (0.54 m)*(0.40 m) = 0.216 m²

then, we apply the formula

ΔL = P*L/(A*E)  ⇒ P = ΔL*A*E/L

⇒  P = (3*10⁻⁴ m)*(0.216 m²)*(95*10⁹ Pa)/(0.25 m)

⇒  P = 24624000  N = 24.624*10⁶ N

Now we can use the equation

σ = P/A

⇒  σ = (24624000  N)/(0.216 m²) = 114000000 Pa = 114 MPa > 80 MPa

So σ > σmax  we use σmax

⇒  P = σmax*A = (80*10⁶ Pa)*(0.216 m²) = 17280000 N = 17.28*10⁶ N

7 0
3 years ago
What is the mass of an object if a force of 34 N produces an acceleration of 4.0 m/s squared​
mrs_skeptik [129]

Answer:

8.5 kg

Explanation:

F = ma

34 N = m(4.0m/s^2)

m = 8.5 kg

6 0
3 years ago
If the Earth and distant stars were stationary (motionless) in space, what would we observe about the wavelength from these star
dangina [55]
1) In the first case, the correct answer is
<span>A.Wavelengths measured would match the actual wavelengths emitted.
In fact, the stars are not moving relative to Earth, so there is no shift in the measured wavelength.

2) In this second case, the correct answer is
</span><span>A.Wavelengths measured would be shorter than the actual wavelengths emitted.
</span>in fact, since the stars in this case are moving towards the Earth, then apparent frequency of their emitted light will be larger than the actual frequency, because of the Doppler effect, according to the formula:
f'= \frac{c}{c+v_s} f_0
where f0 is the actual frequency, f' the apparent frequency, c the speed of light and vs the velocity of the source (the stars) relative to the obsever (Earth). Vs is negative when the source is moving towards the observer, so the apparent frequency f' is larger than the actual frequency f0. But the wavelength is inversely proportional to the frequency, so the apparent wavelength will be shorter than the actual wavelength.
6 0
3 years ago
The statement that "the lowest energy configuration for an atom is theone having the maximum number of unpaired electrons allowe
Mila [183]

Answer:

"The lowest energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by thePauli principle in a particular set of degenerate orbitals" is known as Hund's rule.

Explanation:

Pauli's Exclusion principle states that "two or more electrons can not have the same values of the set of all quantum numbers in an atom or a molecule".

So, the given statement <em>is not</em> Pauli's Exclusion principle.

Hund's rule states that the lowest energy configuration of an atom is that one in which the maximum number of parallel spins of the electrons are present.

The given statement is "The lowest energy configuration for an atom is the one having the maximum number of unpaired electrons allowed by the Pauli principle in a particular set of degenerate orbitals", which is same as the Hund's rule.

Thus, the given statement is Hund' rule.

Heisenberg's uncertainty principle states that the momentum and position of an object can not be measured exactly at the same time.

So, the given statement <em>is not</em> Heisenberg's uncertainty principle.

Aufbau principle tells about the filling of the electrons in subshells of an atom. Therefore, the given statement <em>is not </em>Aufbau principle.

3 0
3 years ago
Laura leaves her house to go to the mall to pick out a gift for her grandma. On her way back home she stopped to grab some coffe
poizon [28]
Displacement is zero. That’s because she ended up where she started.
7 0
4 years ago
Other questions:
  • SI unit for electrical current
    12·1 answer
  • Which of these is exhibiting kinetic energy? Which of these is exhibiting kinetic energy? the high-energy phosphate bonds of a m
    7·1 answer
  • What is the moment of inertia i of this assembly about the axis through which it is pivoted?
    15·1 answer
  • How did the magnet’s density measurement using the Archimedes’ Principle compare to the density measurement using the calculated
    6·1 answer
  • A student solving for the acceleration of an object has applied appropriate physics principles and obtained the expression a = a
    9·1 answer
  • Convert Rev/min to rad/s x 2pie/60?<br><br> Anyone knows this please?
    11·1 answer
  • I need help pleaseeeeeeeeeeeeeeeee
    14·2 answers
  • A chunk of ice with a mass of 1.2 kg melts and absorbs 3.33 x 10³J of energy. Which best describes what has happened in this sys
    15·1 answer
  • How does changing the amount of copper wire affect an electromagnet’s strength?
    6·1 answer
  • Draw a stationary wave and show the position of node and antinode​
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!