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ziro4ka [17]
3 years ago
8

How long does it take light from the nearest star other than the Sun to reach Earth? A) Less than 1 second B) About 1 hour C) Ab

out 1 month D) About 4 years
Chemistry
1 answer:
andrew-mc [135]3 years ago
5 0

Your answer should be D. About 4 years. Hope this helps! =^-^=

<em>(The light reflected from the surface of the Moon takes only a second to reach Earth. The Sun is more than 8 light-minutes away. And so, if the light from the nearest star (Alpha Centauri) takes more than 4 years to reach us, we're seeing that star 4 years in the past.) Quora.com</em>

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How many grams are in 116 mg? Express your answer numerically in grams
Lisa [10]

Answer:

0.116 grams

We can use King Henry Died Unusually Drinking Chocolate Milk

4 0
3 years ago
Read 2 more answers
Consider the following reaction: A(g)⇌2B(g). Find the equilibrium partial pressures of A and B for each of the following differe
Illusion [34]

Answer:

a. Kp=1.4

P_{A}=0.2215 atm

P_{B}=0.556 atm

b.Kp=2.0 * 10^-4

P_{A}=0.495atm

P_{B}=0.00995 atm

c.Kp=2.0 * 10^5

P_{A}=5*10^{-6}atm

P_{B}=0.9999 atm

Explanation:

For the reaction  

A(g)⇌2B(g)

Kp is defined as:

Kp=\frac{(P_{B})^{2}}{P_{A}}

The conditions in the system are:

          A                    B

initial   0                1 atm

equilibrium x       1atm-2x

At the beginning, we don’t have any A in the system, so B starts to react to produce A until the system reaches the equilibrium producing x amount of A. From the stoichiometric relationship in the reaction we get that to produce x amount of A we need to 2x amount of B so in the equilibrium we will have 1 atm – 2x of B, as it is showed in the table.    

Replacing these values in the expression for Kp we get:

Kp=\frac{(1-2x)^{2}}{x}

Working with this equation:

x*Kp=(1-2x)^{2} - -> x*Kp=4x^{2}-4x+1- - >4x^{2}-(4+Kp)*x+1=0

This last expression is quadratic expression with a=4, b=-(4+Kp) and c=1

The general expression to solve these kinds of equations is:

x=\frac{-b(+-)*\sqrt{(b^{2}-4ac)}}{2a} (equation 1)

We just take the positive values from the solution since negative partial pressures don´t make physical sense.

Kp = 1.4

x_{1}=\frac{(1.4+4)+\sqrt{(-(1.4+4)^{2}-4*4*1)}}{2*4}=1.128

x_{1}=\frac{(1.4+4)-\sqrt{(-(1.4+4)^{2}-4*4*1)}}{2*4}=0.2215

With x1 we get a partial pressure of:

P_{A}=1.128 atm

P_{B}=1-2*1.128 = -1.256 atm

Since negative partial pressure don´t make physical sense x1 is not the solution for the system.

With x2 we get:

P_{A}=0.2215 atm

P_{B}=1-2*0.2215 = 0.556 atm

These partial pressures make sense so x2 is the solution for the equation.

We follow the same analysis for the other values of Kp.

Kp=2*10^-4

X1=0.505

X2=0.495

With x1

P_{A}=0.505atm

P_{B}=1-2*0.505 = -0.01005 atm

Not sense.

With x2

P_{A}=0.495atm

P_{B}=1-2*0.495 = 0.00995 atm

X2 is the solution for this equation.  

Kp=2*10^5

X1=50001

X2=5*10^{-6}

With x1

P_{A}=50001atm

P_{B}=1-2*50001=-100001atm

Not sense.

With x2

P_{A}= 5*10^{-6}atm

P_{B}=1-2*5*10^{-6}= 0.9999 atm

X2 is the solution for this equation.  

8 0
4 years ago
A device that does work with only one movement and changes the size or direction of a force is a(n) ____.
worty [1.4K]

Answer:

A device that does work with only one movement and changes the size or direction of a force is a simple machine.

Explanation:

  • For applying force, any used basic mechanical devices are simple machines.
  • Simple machine changes the direction as well as the amplitude of the applied force i.e. we can increase or decrease the magnitude of the force.
  • A simple machine is the most basic mechanism to use the force as we need in big mechanical machines.
  • Some of the examples of simple machines are inclined plane, lever, wedge, wheel and axle, pulley, and screw.
6 0
3 years ago
Which solution contains the smallest number of moles of sucrose (c12h22o11, molar mass = 342.30 g/mol)? 2,000 ml of a 5.0 × 10–5
Iteru [2.4K]

> 2,000 mL of a 5.0 × 10–5% (w/v) sucrose solution 

5.0 × 10–3 g/mL * 2000 mL * (1 mol / 342.30 g) = 0.0292 mol

<span>
> 2,000 mL of a 5.0 ppm sucrose solution</span>

5 grams / 1000000 mL * 2000 mL* (1 mol / 342.30 g) = 0.0000292 mol

 <span>
> 20 mL of a 5.0 M sucrose solution </span>

5.0 M * 0.020 L = 0.1 mol

 

 

Answer:

<span>2,000 mL of a 5.0 ppm sucrose solution</span>

5 0
4 years ago
Kepler and Newton studied the movement of planets. Kepler studied the speed of the planets while Newton studied the forces that
nasty-shy [4]
Kepler did not study the speed of the planets, rather, he studied how the planets move in the solar system. He proposed three laws. As a summary, he described that the planets move around the sun in the shape of an ellipse (orbit), and the Sun being one of the foci. Then, he proposed the period for the planet to complete one revolution around the Sun. 

On the other hand, Newton studied the forces acting on the planet (or any object in space) that explain how the planets move around the solar system as described by Kepler. Also, Kepler's observations only apply to planets and not the moons or satellites. Thus, Kepler only made laws from observations, while Newton based it from underlying principles that led him to mathematical equations such as the law of universal gravitation.
4 0
3 years ago
Read 2 more answers
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