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4 years ago

What is causing his hair to stand up and separate from each other?

Chemistry

1 answer:

algol [13]4 years ago

6 0

Answer:

This would most likely be static electricity.

Explanation:

Say you were to rub a balloon on your hair, your hair would stand up and be separated from each other.

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Which of the following fractions can be used in the conversion of 1000 mL to the unit m3? 1L/1ML 1CM^3/1ML 1CM^-3/1ML 1M^3/1L

Flauer [41]

The conversion that can be used is 1 cm³ / mL
After multiplying by this conversion, we get:
1000 mL * (1 cm³ / mL) = 1000 cm³

Next, we may convert directly from cm³ to m³ by:
1 m = 100 cm
1 m³ = 100³ cm³

Using this conversion, we get the volume in m³ to be:
0.001 m³

6 0

4 years ago

A) A red laser pointer emits light with a wavelength of 670 nm. What is the frequency of this light?

Serga [27]

Answers:

a) $4.47(10)^{14} Hz$

b) $178254.16 J$

c) $2.96(10)^{-19} J$

Explanation:

a) The following equation states the relation between the wavelength $\lambda$ and the frequency $\nu$ of the light:

$c=\lambda \nu$ (1)

Where:

$c=3(10)^{8}m/s$ is the speed of light in vacuum

$\lambda=670 nm=670(10)^{-9}m$ is the wavelength of the light emitted by the laser pointer

$\nu$ is the frequency

Finding $\nu$ :

$\nu=\frac{c}{\lambda}$ (2)

$\nu=\frac{3(10)^{8}m/s}{670(10)^{-9}m}$ (3)

$\nu=4.47(10)^{14} Hz$ (4) This is the frequency

b) The energy $E$ of a 670 nm photon is given by:

$E=\frac{hc}{\lambda}$ (5)

Where:

$h=6.626(10)^{-34}\frac{m^{2}kg}{s}$ is the Planck constant

Then:

$E=\frac{(6.626(10)^{-34}\frac{m^{2}kg}{s})(3(10)^{8}m/s)}{670(10)^{-9}m}$ (6)

$E=2.96(10)^{-19} J$ (7) This is the energy of one photon

Now we have to find the energy of 1 mole of these 670 nm photons by multiplying (7) by the Avogadro's number ( $N_{A}=6.0221(10)^{23}/mol$ ):

$E N_{A}=(2.96(10)^{-19} \frac{J}{photon})(6.0221(10)^{23}\frac{photon}{mol})$ (8)

$E N_{A}=178254.16 J$ This is the energy of 1 mole of 670 nm photons

c) The ground state of an atom is the point where the energy of the system is zero. This means the ground state energy is $E_{o}=0 J$ and the energy gap $\Delta E$ is:

$\Delta E=E-E_{o}$

$\Delta E=2.96(10)^{-19} J-0 J=2.96(10)^{-19} J$

Hence, the energy gap has the same value that was already calculated in part b (7), which is the energy of 670 nm photons:

$E=2.96(10)^{-19} J$

This is the energy of a single 670 nm photon, which is emitted when the excited electrons return to the ground state.

That is why the wavelength (color) of the light of the laser pointer is 670 nm (red).

8 0

4 years ago

How long does it take electrons to get from the car battery to the starting motor? Assume the current is 137 A and the electrons

WARRIOR [948]

Answer:

t = 55.79 min

Explanation:

First, the problem is asking for calculate the time that it takes electrons from the battery to the motor.

The general formula to calculate time is:

t = d/V (1)

Where:

d: distance or length

V: speed

Now, we don't have data of speed, but we can know an expression of current density in function of the distance which is the following:

J = n*q*V (2)

Where:

q: charge of the particle (1.6x10^-19 C)

n: number of charge carriers per unit of volume

Current density (J) is actually current per Area so:

J = I/A (3)

Replacing (3) in (2) we have:

I/A = nqV

Solving for V:

V = I/Anq (4)

Finally, if we replace this expression in (1) we have:

t = nqAd / I (5)

Now, the value of n, it's not given but it can be calculated because we have mass density, molar mass and avogadro's number, so this value of "n" can be calculated using the following expression:

n = D * Av / MM (6)

Where:

D: mass density (kg/m³)

Av: avogadro number (6.02x10^23 atom/mol)

MM: molar mass (kg/mol)

Putting the data that we know to calculate n we have:

n = 8960 * 6.02x10^23 / 0.0635

n = 8.49x10^28 atom/m³

Now with the value of n, we can finally calculate the time:

t = nqAd / I

A is the area and it should be in m²: 44.6 mm² / 1x10^6 m = 4.46x10^-5 m²

d is the length in meter: 75.7 cm / 100 cm/m = 0.757 m

so replacing these data in (5):

t = 8.49x10^28 * 1.6x10^-19 * 4.46x10^-5 * 0.757 / 137

t = 3,347.63 s

But the answer is in minute so:

t = 3,347.63 / 60

t = 55.79 min

so the electrons takes 56 min aprox. to go from the car battery to the starting motor.

4 0

3 years ago

48. What is the mass in grams for a 1000-ml volume (1 liter) of

Orlov [11]

Answer:

22420g

Explanation:

Iridium is 22.42 grams for every one milliliter. We have 1000 millilitres, so 1000 x 22.42 = 22420g of iridium.

Hope this helps, let me know if you have any questions :)

8 0

3 years ago

Write an equation for the decomposition of sodium iodide.

nikitadnepr [17]

NaIO3 = NaI + O2 | Chemical reaction and equation.

5 0

3 years ago