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3 years ago

(ii) The Cu2+ ions are attracted to the negative electrode, where they are reduced to produce copper atoms.

1 answer:

5 0

Electrolyte for the electrolysis is copper(II) sulfate
CuSO₄ = Cu²⁺ + SO₄²⁻

the reaction at the negative electrode
(cathode -) Cu²⁺ + 2e⁻ = Cu⁰

and...
(anode +) 2H₂O - 4e⁻ = O₂ + 4H⁺

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Is crumpling a piece of paper chemical changes

kenny6666 [7]

No, because you are not changing the chemical make-up of the paper

8 0

3 years ago

Read 2 more answers

If 10 grams of potassium chlorate decompose to form potassium chloride and oxygen gas inside a 500 mL container at a temperature

Gekata [30.6K]

Answer:

10 atm

Explanation:

There's a lot to do here, but lets take it one step at a time. First, let's write a balanced equation for the decomposition of potassium chlorate into potassium chloride and oxgyen gas.

2 KClO3 → 2 KCl + 3 O2

Now let's find the moles of the KClO3 (molar mass 122.55 g/mol) that we have take 10 g/122.55 g/mol, grams will cancel and we are left with 0.0816 moles. lets divide that by two since we have a two in front of the KClO3 in the equation, and then multiply that number by 5 since it's the total moles of products, in summary, multiply by 5/2 to get 0.204 moles.

Now that we know the moles of our products, let's plug some stuff into the ideal gas law PV = nRT. We are looking for P so let's solve for that. P = (nRT)/V, now let's plug in our values. Make sure V is converted to liters so 0.5 L. And convert celcius to kelvin by adding 273

P = ((0.204 moles)(318 K)(0.08206 L atm mol^-1 K^-1))/0.5 L

A lot of units cancel, and we get about 10.65 atm, if you don't want the answer in atm, you can find a conversion equation. But let's round to sig figs for now, which will bring us to 10 atm.

3 0

2 years ago

1. Fred is walking at 1.7 m/s, he sees a dollar and runs at 2.5 m/s in 1.5 seconds.

Firdavs [7]

Answer:

Acceleration is the rate of change of velocity. Usually, acceleration means the speed is changing, but not always. When an object moves in a circular path at a constant speed, it is still accelerating, because the direction of its velocity is changing.

Explanation:

It goes with velocity

5 0

3 years ago

Al wonders if adding salt to water will affect how long it takes the water to

love history [14]

The hypothesis is that salt water freezes faster than fresh water.

The dependent variable is time taken for ice to appear.

The independent variable is presence or absence of salt

The constants are the amount of water in each tray, freezing conditions and length of time of exposure to freezing condition.

The control group is the tray to which salt was not added

The experimental group is the tray to which salt was added

The presence of solutes in a solution causes the freezing point depression.

A solution is made up of a solute and a solvent. In the presence of a solute, the freezing point of a pure solvent is decreased. This is because freezing point is a colligative property.

Colligative properties depend on the amount of solute present.

Hence, the pure water freezes faster (ice begin to appear earlier) than the salt water.

The hypothesis put forward in this experiment was found to be invalid by the experiment.

For more about colligative properties, see

brainly.com/question/10323760

6 0

3 years ago

Sometimes in lab we collect the gas formed by a chemical reaction over water (see sketch at right). This makes it easy to isolat

ad-work [718]

Answer:

The correct answer is 0.00582 grams.

Explanation:

In order to solve the question, let us consider the vapor pressure of H2O, as hydrogen gas is collected over water, therefore, we have to consider the vapor pressure of water in the given case. Let us assume that the pressure is 760 torr or 1 atm.

It is known that the vapor pressure of water at 40 degree C is 53.365 torr (Based on the data).

Therefore, the pressure of H2 will be,

P = 760-55.365 = 704.635 torr or 704.635/760 = 0.9272 atm

The volume of the hydrogen gas collected in the tube is 80 ml or 0.08 L

Temperature in Kelvin will be 40+273 = 313 K

To calculate the moles of hydrogen (H2) gas, there is a need to use the ideal gas equation, that is, PV= nRT, in this R is the gas constant, whose value is 0.0821 L atm/molK, and n is the moles of the gas.

By inserting the values in the equation we get:

PV = nRT

n = PV/RT = 0.9272 *0.08 / 0.0821 * 313

n = 0.00289 moles

The mass of H2 will be moles * molar mass = 0.00289 * 2.016

= 0.00582 grams.

7 0

3 years ago