It is possible for a particular element to have various number of neutrons

What is the mass of HF produced by three reaction of 3.0 10 to the 23 molecules of H2 with excess F2

JulijaS [17]

Answer:

It is 20. g HF

Explanation:

H2 + F2 ==> 2HF ... balanced equation

Since the question is asking us to find the mass of product formed, we will want to first convert the molecules of H2 into moles of H2 (we could do this at the end of the calculations, but it's just as easy to do it now).

moles of H2 present (using Avogadro's number):

3.0x1023 molecules H2 x 1 mole H2/6.02x1023 molecules = 0.498 moles H2

From the balanced equation, we see that 1 mole H2 produces 2 moles HF. Therefore, we can now find the theoretical mass of HF produced from 0.498 moles H2:

0.498 moles H2 x 2 moles HF/1 mol H2 = 0.996 moles HF formed.

The molar mass of HF = 20.01 g/mole, thus...

0.996 moles HF x 20.01 g/mole = 19.93 g HF = 20. g HF formed (to 2 significant figures)

6 0

2 years ago

Use the picture below to answer the question. What is true about the relationship between the wavelength and the frequency of th

KatRina [158]

The picture is not loading as it requires a sign in.
However, I can tell you how to solve this.

Answer:
As the wavelength gets shorter (closer together), the frequency of the wave increases.

Explanation:
The relation between frequency and wavelength can be described by the help of velocity as follows:
velocity = frequency * wavelength
This means that:
frequency = velocity / wavelength
Noting this equation, we will find that:
The frequency and the wavelength are inversely proportional to each other. This means that as the frequency increases, the wavelength decreases and vice versa.
Now, examining the choices given, we can find that the only statement showing the inverse relation between frequency and wavelength is:
As the wavelength gets shorter (closer together), the frequency of the wave increases.

Hope this helps :)

8 0

3 years ago

The mass of a radioactive substance follows a continuous exponential decay model, with a decay rate parameter of 8.1% per day. f

Elanso [62]

The general equation for radioactive decay is;
N = N₀e^(-λt)
x - decay constant (λ) - rate of decay
t- time
N - amount remaining after t days , since we are calculating the half life, amount of time it takes for the substance to to be half its original value, its N₀/2
N₀ - amount initially present
substituting the values
N₀/2 = N₀e^(-0.081t)
0.5 = e^(-0.081t)
ln (0.5) = -0.081t
-0.693 = -0.081t
t = 0.693 / 0.081
= 8.55
half life of substance is 8.55 days

5 0

2 years ago

Se requieren preparar 1500 ml de una solución al 55% en masa de hidróxido de calcio, sabiendo que la densidad de dicha solución

Masja [62]

Respuesta:

968 g Ca(OH)₂

Explicación:

Paso 1: Calcular la masa de solución

Tenemos 1500 mL de una solución cuya densidad es 1.17 g/mL, es decir, 1 mL de solución tiene una masa de 1.17 g.

1500 mL × 1.17 g/mL = 1.76 × 10³ g

Paso 2: Calcular la masa de hidróxido de calcio en 1.76 × 10³ g de solución

La solución tiene una concentración de 55% en masa de hidróxido de calcio, es decir, cada 100 gramos de solución hay 55 gramos de hidróxido de calcio.

1.76 × 10³ g Solución × 55 g Ca(OH)₂/100 g Solución = 968 g Ca(OH)₂

6 0

2 years ago

The vapor pressure of diethyl ether (ether) is 463.57 mm Hg at 25 °C. A nonvolatile, nonelectrolyte that dissolves in diethyl et

Alexxx [7]

Answer: The vapor pressure of solution is 459.17 mmHg

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)