Answer: True
Explanation:
I just took the test and got it right
We will assume that the wave is moving in free space, thus, the velocity of the wave would be equal to the speed of light = 3 * 10^8 meters/sec
The velocity of the wave can be calculated using the following rule:
velocity = frequency * wavelength where:
velocity = 3 * 10^8 m/sec
frequency = 2500 Hz
wavelength is the unknown that we want to calculate.
Substitute with the givens in the above equation to get the wavelength as follows:
3 * 10^8 = 2500*wavelength
wavelength = 120 * 10^3 meters
Answer : The value of equilibrium constant (K) is, 
Explanation :
First we have to calculate the concentration of 

and,

and,

Now we have to calculate the value of equilibrium constant (K).
The given chemical reaction is:

The expression for equilibrium constant is:
![K=\frac{[N_2O]^2}{[N_2][O_2]}](https://tex.z-dn.net/?f=K%3D%5Cfrac%7B%5BN_2O%5D%5E2%7D%7B%5BN_2%5D%5BO_2%5D%7D)
Now put all the given values in this expression, we get:


Thus, the value of equilibrium constant (K) is, 
<u>Answer:</u> The concentration of
ions are 2.797 ppm and 0.212 ppm respectively.
<u>Explanation:</u>
To calculate the mass of solution, we use the equation:

Volume of gold = 100 L = 100000 mL (Conversion factor: 1 L = 1000 mL)
Density of gold = 1.001 g/mL
Putting values in above equation, we get:

To calculate the concentration in ppm (by mass), we use the equation:

- <u>Calculating the concentration of calcium ions:</u>
Mass of
ions = 0.280 g
Putting values in above equation, we get:

- <u>Calculating the concentration of magnesium ions:</u>
Mass of
ions = 0.0220 g
Putting values in above equation, we get:

Hence, the concentration of
ions are 2.797 ppm and 0.212 ppm respectively.