1. What is a metal replacement reaction?

Calculate the pH during the titration of 30.00 mL of 0.1000 M HCOOH(aq) with 0.1000 M NaOH(aq) after 29.3 mL of the base have be

pashok25 [27]

Answer:

3.336.

Explanation:

Herein, the no. of millimoles of the acid (HCOOH) is more than that of the base (NaOH).

So, concentration of excess acid = [(NV)acid - (NV)base]/V total = [(30.0 mL)(0.1 M) - (29.3 mL)(0.1 M)]/(59.3 mL) = 1.18 x 10⁻³ M.

For weak acids; [H⁺] = √Ka.C = √(1.8 x 10⁻⁴)(1.18 x 10⁻³ M) = 4.61 x 10⁻⁴ M.

∵ pH = - log[H⁺].

∴ pH = - log(4.61 x 10⁻⁴) = 3.336.

7 0

3 years ago

An unknown gaseous substance has a density of 1.06 g/L at 31 °C and 371 torr. If the substance has the following percent composi

Anarel [89]

Answer:

C) C4H6 - Right answer

Explanation:

Let's combine the Ideal Gases Law with density to get the molecular formula for the unknown gas.

Density = mass / volume

1.06 g /L means that 1.06 grams of compound occupy 1 liter of volume.

P . V = n . R . T

Pressure in Torr must be converted to atm

760 Torr are 1 atm

371 Torr are __ (371 .1)/760 = 0.488 atm

0.488 atm . 1L = 1.06g/MM . 0.082 . 304K

(0.488 atm . 1L) / 0.082 . 304K = 1.06g/ MM

Mass / Molar mass = Moles → That's why the 1.06 g / MM

0.0195 mol = 1.06g / MM

1.06g/0.0195 mol = MM → 54.3 g/m

Now, let's use the composition

100 g of compound have 88.8 g of C

54.3 g of compound have ___ (54.3 . 88.8) /100 = 48 g of C

100 g of compound have 11.2 g of H

54.3 g of compound have __ (54.3 . 11.2)/100 = 6 g of H

48 g of C are included un 4 atoms

6 g of H are included in 6 atoms

4 0

3 years ago

Which diagram above has 4 valence electrons?

Gemiola [76]

Answer:

answer A has four valence electrons

Explanation:

The outer shell has 4 electrons, which are considered the valence electrons

8 0

3 years ago

HURRY PLEASE

katrin2010 [14]

Answers:

Question 1:

The diagram for gallium will have flat, horizontal lines at 30 and 2204 °C.

Questoin 2:

The diagram for methane will have a diagonal line representing the liquid phase between -183°C and -162°C.

Question 3:

For gold, the boiling point corresponds to the y-value at 2856 °C of the top horizontal line

Question 4.

For nitrogen, the line at -210°C will be flat, which represents the change from a solid to a liquid

Explanations:

Question 1:

The diagram for gallium will have flat, horizontal lines at 30 and 2204 °C.

The table shows that the melting point of gallium is 30°C and its boiling point is 2204°C.

Melting point is the temperature at which the substace changes its state from solid to liquid. During that change, the temperature of the substance does not change, because the heat supplied is used to accomplish the phase change. So, the temperature is constant and that means that portion of the diagram is flat.

The same is valid during boiling: the temperature remains constant while the substance is passing from liquid to gas at the boiling point.

Questoin 2:

The diagram for methane will have a diagonal line representing the liquid phase between -183°C and -162°C.

Between the melting (-183°C) and boiling (-162°C) points of methane, its temperature will increase more or less linearly, which is represented with a diagonal (slant) line between those points. During this interval the heat is used to increase the temperature and no phase of change happens.

Question 3:

For gold, the boiling point corresponds to the y-value at 2856 °C of the top horizontal line

The table shows that the boiling point of gold is 2,856°C.

In a temperature-vs.-time diagram the temperature is represented on the vertical axis (y-value) and the time is represented on the horizontal axis.

Since, the temperature of the substance does not change during boiling, the line during the time that this change of phase is happening is flat. And since this temperatue is higher than the melting temperature, this is the top horizontal line in the diagram.

Question 4.

For nitrogen, the line at -210°C will be flat, which represents the change from a solid to a liquid

The table shows that the melting point of nitrogen is -210°C, that means that the temperature will remain constant at -210°C while the substance is absorbing heat to pass from solid to liquid.

In conclusion, you must remember that all the phase changes, melting (from solid to liquid), freezing (from liquid to solid), boilng (from liquid to gas), and condensing (from gas to liquid) happens at constant temperature, and so the temperature - vs. - time diagrams show flat lines (constant y-values) during those intervals of time.

4 0

3 years ago

Read 2 more answers

You wish to make a 0.375 M hydroiodic acid solution from a stock solution of 6.00 M hydroiodic acid. How much concentrated acid

cluponka [151]

We need to add 2.09 mL of concentrated acid to obtain 75 mL of 0.335 M HBr solution.

You are performing a dilution of HBr going from a concentration of 12M to 0.335M, and you want to end up with a final volume of 75 ml of the dilute solution.

Consider the dilution formula: M1V1 = M2V2.

The basis behind this formula is that the number of moles of the acid before and after the dilution must remain constant.

M1 = the molarity of the stock solution,

M2 = the molarity of the diluted solution,

V2 = the final volume of the diluted solution.

In this case, we need to determine V1, which is the volume of the stock solution used to prepare the diluted sample. With this knowledge, we can plug our numbers into the equation and we obtain the following:

(12 mol/L)*V1 = (0.335mol/L)*(0.075L).

Keeping in mind that molarity is the moles of a substance in one liter of solution, we will use mol/L instead of M. By doing this, we are reminded that in order to use this equation, we must convert 75 mL into units of liters.

After rearranging the equation and solving for V1, we find that V1 = 0.00209L.

Finally, we must convert back from liters to mL by multiplying the final answer by 1000.

This way we end up with V1 = 2.09 mL.

This means that we need to add 2.09 mL of concentrated acid to obtain 75 mL of 0.335 M HBr solution.

Learn more about molarity here: brainly.com/question/23243759

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3 0

2 years ago