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Evgesh-ka [11]
3 years ago
14

A 1.45 g sample of phosphorus burns in air and forms 2.57 g of a phosphorus oxide. Calculate the empirical formula of the oxide.

Express your answer as a chemical formula.
Chemistry
1 answer:
bija089 [108]3 years ago
5 0

Answer:

P2O3

Explanation:

Firstly, we know that the phosphorus would absorb oxygen from air to form its oxide. We already know the mass of the phosphorus, we can get the mass of the oxygen by subtracting the mass of the phosphorus from the mass of the oxide.

The mass of the oxygen is 2.57 - 1.45 = 1.12g

From here, we covert these masses to moles by dividing by the atomic masses of phosphorus and oxygen respectively.

The atomic mass of phosphorus is 31 while that of oxygen is 16.

P = 1.45/31 = 0.046774193548

O = 1.12/16 = 0.07

We now divide by the smallest which is that of phosphorus.

P = 0.046774193548/ 0.046774193548= 1

O = 0.07/ 0.046774193548 = 1.5

We then multiply the answers by 2 for conversion to whole numbers. Making P = 2 and O = 3

The empirical formula is thus P2O3

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What is the nuclear binding energy for thorium-234? 2.78 × 10-10 J 3.36 × 10-14 J 1.67 × 1017 J 5.35 x 10-23 J
grin007 [14]
The correct option is A.
To calculate the binding energy, you have to find the mass defect first.
Mass defect = [mass of proton and neutron] - Mass of the nucleus
The molar mass of thorium that we are given in the question is 234, the atomic number of thorium is 90, that means the number of neutrons in thorium is 
234 - 90 = 144.
The of proton in thourium is 90, same as the atomic number.
Mass defect = {[90 * 1.00728] +[144* 1.00867]} - 234
Note that each proton has a mass of 1.00728 amu and each neutron has the mass of 1.00867 amu.
Mass defect = [90.6552 + 145.24848] - 234 = 1.90368 amu.
Note that the unit of the mass is in amu, it has to be converted to kg
To calculate the mass in kg
Mass [kg] = 1.90368 * [1kg/6.02214 * 10^-26 = 3.161135 * 10^-27
To calculate the binding energy
E = MC^2
C = Speed of light constant = 2.9979245 *10^8 m/s2
E = [3.161135 * 10^-27] * [2.9979245 *10^8]^2
E = 2.84108682069 * 10^-10.
Note that we arrive at this answer because of the number of significant figures that we used.
So, from the option given, Option A is the nearest to the calculated value and is our answer for this problem.

8 0
3 years ago
Read 2 more answers
WHAT IS THE UNKNOWN METAL?
gavmur [86]

Answer:

The Unknown V was shiny and gray, but it was a lightweight metal. THE UNKNOWN METALS5V was aluminum, which has a density of 2.75 g/ml(Smith, 2019).

Explanation:

pls mark me as brainleast and folow me

6 0
3 years ago
What is Newton's first law of motion? How can you describe the effect of a vehicle restraint using Newton's first law of motion?
pav-90 [236]

Answer:

Newton's First Law states that an object in motion will stay in motion, an object at rest will stay at rest, at a constant velocity, unless an unbalanced force acts upon it.  

Newtons First law of motion has to do with seat belts because think about it, what happens when we don't wear a seat belt and our vehicle comes to a quick stop. What happens to you? You move forward and stay in motion until an unbalanced force acts upon you. Now what is an unbalanced force? An unbalanced force is one that is not opposed by an equal and opposite force operating directly against the force intended to cause a change in the object's state of motion or rest. So, when you come to a stop, you wouldn't stop motion unless a force is caused to change your motion and put you at rest. If you were wearing a seat belt, the seat belt would act as the unbalanced force, it would stop you from being in motion.

7 0
2 years ago
A engineer measures the peak power output is 0.3227MW what is the peak power output in kilowatts ?
Lana71 [14]
<h3>Answer:</h3>

322.7 kW

<h3>Explanation:</h3>
  • Power refers to the rate at which work is done.
  • Therefore; Power = Work done ÷ time
  • It is measured in joules per seconds or Watts

In this case, we are required to convert 0.3227 MW to kilowatts

We need to know that;

  • 10^6 watts = 1 Megawatts(MW)
  • 10^3 Watts = 1 kilowatts (kW)

Therefore;

10^3 kW = 1 MW

Therefore, the suitable conversion factor is 10^3kW/MW

Hence;

0.3227 MW is equivalent to;

   = 0.3227 MW × 10^3kW/MW

   = 322.7 kW

Thus, the peak power output is 322.7 kW

3 0
2 years ago
What metalloid has commonly been used as an insecticide due<br> to its effectiveness as a poison.
Taya2010 [7]

Answer:

Arsenic.

Explanation:

Hello there!

In this case, since insecticides are substances that act as poisons to get rid of insects in order to prevent their presence and/or reproduction in houses, companies, crops and others, a substance that has been widely used is the metalloid arsenic due to its direct affection of the insect's body (movement, performance, cellular functions).

In addition, high levels of arsenic in food could cause arsenic poisoning in humans as well, that is why such practice must be properly performed and by using the correct security protocol.

Best regards!

5 0
3 years ago
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