Examine the system of equations.<br> y = 4x +8,<br> y = 4x-1

Hoeveel gram opgeloste stof moet je afwegen om 250 ml KMnO4-oplossing te bereiden met een concentratie van 0,500 mol / L

Hatshy [7]

How many grams of solute do you have to weigh to prepare 250 ml KMnO4 solution with a concentration of 0.500 mol / L

Answer:

19.75g

Explanation:

Given parameters:

Volume of KMnO₄ = 250mL or 0.25L

Concentration of solution = 0.5mol/L

Unknown:

Mass of solute or KMnO₄ = ?

Solution:

To solve this problem, we need to find the number of moles first.

Number of moles = Concentration x volume

Number of moles = 0.5mol/L x 0.25L = 0.125mol

So;

Mass in grams = number of moles x molar mass

Molar mass of KMnO₄ = 39 + 55 + 4(16) = 158g/mol

Mass in grams = 0.125 x 158 = 19.75g

7 0

3 years ago

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A molecule whose ends have opposite electric charge is call a_?

snow_lady [41]

A polar molecule is a molecule whose ends have opposite electric charges. An example of a polar molecule is H2O or water. Water has 1 side which is positive and the other side which is negative. It is a dipole which means that the two sides are not having the same charges.

5 0

3 years ago

A 2.50-l flask contains a mixture of methane (ch4) and propane (c3h8) at a pressure of 1.45 atm and 20°c. when this gas mixture

Cerrena [4.2K]

Answer:- Mole fraction of methane in the original gas mixture is 0.854.

Solution:- From given volume, pressure and temperature, we could calculate the total moles of the gaseous mixture of methane and propane using ideal gas law as:

PV = nRT

$n=\frac{PV}{RT}$

V = 2.50 L

P = 1.45 atm

T = 20 + 273 = 293 K

Let's plug in the values in the equation:

$n=(\frac{1.45*2.50}{0.0821*293})$

n = 0.151

Let's say the solution has X moles of methane. Then moles of propane would be = (0.151 - X)

The combustion equations of methane and propane are:

$CH_4+2O_2\rightarrow CO_2+2H_2O$

$C_3H_8+5O_2\rightarrow 3CO_2+4H_2O$

From methane balanced equation, there is 1:1 mol ratio between methane and carbon dioxide. So, X moles of methane would produce X moles of carbon dioxide.

From balanced equation of propane, there is 1:3 mol ratio between propane and carbon dioxide. So, (0.151 - X) moles of propane would give 3(0.151 - X) moles of carbon dioxide.

So, total moles of carbon dioxide that we would get from methane and propane combustion are:

X + 3(0.151 - X)

From given data, 8.60 g of carbon dioxide are formed by the combustion of gas mixture.

moles of Carbon dioxide = $8.60g(\frac{1mol}{44g})$

moles of carbon dioxide = 0.195 mol

Hence, 0.195 = X + 3(0.151 - X)

Let's solve this for X as:

0.195 = X + 0.453 - 3X

0.195 = 0.453 - 2X

2X = 0.453 - 0.195

2X = 0.258

$X=\frac{0.258}{2}$

X = 0.129

So, there are 0.129 moles of methane in the mixture.

moles of propane = 0.151 - 0.129 = 0.022

mole fraction of methane = $\frac{moles of Methane}{total moles}$

mole fraction of methane = $\frac{0.129}{0.151}$

mole fraction of methane = 0.854

Hence, the mole fraction of methane gas in the original gas mixture is 0.854.

6 0

3 years ago

Where is most of the high-level waste stored in the United States

Anna007 [38]

The correct answer is number 5) at the nuclear reactor site.

Most of the high-level waste stored in the United States is at the nuclear reactor site.

Just people who specialize in the radioactive waste can handle this risky procedure because high-level radioactive waste needs treatment by the experts to truly isolated from the biosphere. Radioactive plants keep the waste deep underground because nobody wants another accident like the one that happened in Chernobyl on April 26, 1986.

The other options of the question were 1) the ocean. 2) mountain peaks. 3) volcanic fissures. 4) salt mines.

8 0

4 years ago

What the common uses for Bohrium?

lora16 [44]

Answer:

Explanation:

Bohrium's most stable isotope, bohrium-270, has a half-life of about 1 minute. It decays into dubnium-266 through alpha decay. Since only a few atoms of bohrium have ever been made, there are currently no uses for bohrium outside of basic scientific research.

5 0

3 years ago

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Examine the system of equations. y = 4x +8, y = 4x-1