CHEMISTRY COLLEGE

Metal vapor deposition is a process used to deposit a very thin layer of metal on a target substrate. A researcher puts a glass slide in the metal vapor deposition chamber and coats the slide with copper. After deposition, the glass slide had increased in mass by 2.26 milligrams. Approximately how many copper atoms were deposited on the glass slide

Answers

Answer 1

Answer:

Answer:

2.14x10¹⁹ atoms of Cu were deposited

Explanation:

The increased in mass of the glass slide is due the deposition of copper.

That means the mass of copper deposited is 2.26mg = 2.26x10⁻³g Cu

To know the copper atoms we need to convert this mass to moles of Cu using molar mass of copper (63.546g/mol), and these moles are converted to atoms using Avogadro's number (6.022x10²³ atoms = 1 mole)

Moles Cu:

2.26x10⁻³g Cu * (1 mol / 63.546g) = 3.556x10⁻⁵ moles Cu

Atoms Cu:

3.556x10⁻⁵ moles Cu * (6.022x10²³ atoms / 1 mole) =

2.14x10¹⁹ atoms of Cu were deposited

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Which is more water soluble hexanoic acid or sodium hexanoate?

A student was asked to prepare exactly 250 mL of a 0.500 M aqueous potassium hydroxide solution. What mass of potassium hydroxide (molar mass = 56.10 g/mol) must the student dissolve in the 250 mL of solution? 1. 28.1 g 2. 3.0 g 3. None of these 4. 14.0 g 5. 7.01 g 6. 56.1 g

Answers

Answer:

Option 5 → 7.01 g

Explanation:

Molarity . volume (L) = Moles

This can help us to determine the moles of KOH that are in the solution.

We convert the volume from mL to L → 250 mL . 1L / 1000mL = 0.250 L

0.5 mol /L . 0.250L = 0.125 moles of KOH

Now, we only have to convert the moles to mass, by the molar mass:

Moles . molar mass = mass → 0.125 mol . 56.1 g/mol = 7.01 g

Answer:

We need 7.01 grams of KOH (option 5)

Explanation:

Step 1: Data given

Volume aqueous KOH solution = 250 mL = 0.250 L

Molarity = 0.500 M

Molar mass of KOH = 56.10 g/mol

Step 2: Calculate moles KOH

Moles KOH = molarity * volume

Moles KOH = 0.500 M * 0.250 L

Moles KOH = 0.125 moles

Step 3: Calculate mass of KOH

Mass KOH = moles KOH * molar mass KOH

Mass KOH = 0.125 moles * 56.10 g/mol

Mass KOH = 7.01 grams

We need 7.01 grams of KOH

55:28An object is moving across a surface, but it does not gain or lose speed. Which best describes the object's force?
The net force is positive.
The net force is zero.
The positive force is greater than the negative force.
The negative force is greater than the positive force.
ke this and totum
Save and Exit
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Answers

Answer:

The correct answer is - The net force is zero.

Explanation:

When an object moves on the surface with the same or constant acceleration which means there is no gain or loss of the speed it shows that all the forces of the object are at a point of zero.

If there would be any force applied on the object there must be some change in the velocity or acceleration but in this case there is no loss or gain of speed which means there is the object's net force is zero.

Therefore, option B is correct.

At 25.0 ⁰C the henry's law constant for hydrogen sulfide(H2S) gas in water is 0.087 M/atm. Caculate the mass in grams of H2S gas that can be dissolved in 400.0 ml of water at 25.00 C and a H2S partial pressure of 2.42atm.

Answers

Answer: The mass of hydrogen sulfide that can be dissolved is 2.86 grams.

Explanation:

Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the gas.

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_(H_2S)=K_H* p_(liquid)$

where,

$K_H$ = Henry's constant = $0.087M/atm$

$p_(H_2S)$ = partial pressure of hydrogen sulfide gas = 2.42 atm

Putting values in above equation, we get:

$C_(H_2S)=0.087M/atm* 2.42atm\n\nC_(H_2S)=0.2105M$

To calculate the mass of solute, we use the equation used to calculate the molarity of solution:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}* 1000}{\text{Molar mass of solute}* \text{Volume of solution (in mL)}}$

We are given:

Molarity of solution = 0.2105 M

Molar mass of hydrogen sulfide = 34 g/mol

Volume of solution = 400.0 mL

Putting values in above equation, we get:

$0.2105M=\frac{\text{Mass of hydrogen sulfide}* 1000}{34g/mol* 400.0mL}\n\n\text{Mass of }H_2S=(0.2105* 34* 400)/(1000)=2.86g$

Hence, the mass of hydrogen sulfide that can be dissolved is 2.86 grams.

What is the pOH of a 7.9 x 10 ^-4 M OH- solution?

pOH= ?

Answers

Answer: pOH of the given hydroxide ion concentration is 3.10

Explanation:

pOH is defined as the negative logarithm of hydroxide ion concentration. It is represented by the equation:

$pOH=-\log[OH^-]$

We are given:

Hydroxide ion concentration, $[OH^-]=7.9* 10^(-4)M$

Putting values in above equation, we get:

$pOH=-\log(7.9* 10^(-4))\n\npOH=3.10$

Hence, pOH of the given hydroxide ion concentration is 3.10

pOH is defined as -log([OH-]).

pOH = -log([OH-]) = -log(7.9 * 10^-4) = 3.1

Hope this helps!

What isotope has a mass number of 18 and an atomic number of 7

Answers

Answer:

nitrogen 18

nitrogen has an atomic number of 7

What is the hydronium (H3O+) concentration of a solution with a pH of 3.60? A. 2.5 × 10-4 M
B. 3.0 × 10-4 M
C. 4.0 × 10-11 M
D. 4.5 × 10-11 M

Answers

Answer:

A. 2.5 × 10⁻⁴ mol·L⁻¹

Explanation:

pH = -log[H₃O⁺]

$[\text{H}_(3)\text{O}^(+)] = 10^{- \text{pH}} \text{ mol/L}$

pH = 3.60

$[\text{H}_(3)\text{O}^(+)] =10^(-3.60)\text{ mol/L}$

$[\text{H}_(3)\text{O}^(+)] = 2.5 * 10^(-4)\text{ mol/L}$

The hydronium concentration of a solution with a pH of 3.60 is $2.5 * 10^-^4 M$ . The correct option is A.

What is pH?

PH is a scale for the measurement of the acidic and basic solutions. The pH of less than 7 are acids and more than 7 are bases.

$\rm pH = -log[H_3O^+]\n\nH_3O^+ = 10^-^p^H\; mol/l$

pH = 3.60

$\rm H_3O^+ = 10^-^3^.^6^0\n\nH_3O^+ = 2.5 * 10^-^4 M$

Thus, the correct option is A.

Learn more about pH

brainly.com/question/15289741

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