1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Lerok [7]
3 years ago
7

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

e and measure the amount of gas produced. Wala Suppose the H, gas evolved by a certain chemical reaction taking place at 40.0 °C is collected over water, using an apparatus something like that in the sketch, and the final volume of gas in the collection tube is measured to be 80.0 mL. Sketch of a gas-collection apparatus Calculate the mass of H, that is in the collection tube. Round your answer to 2 significant digits. You can make any normal and reasonable assumption about the reaction conditions and the nature of the gases. XS?
Chemistry
1 answer:
Viefleur [7K]3 years ago
7 0

Answer:

see explaination

Explanation:

Case 1) When we consider vapor pressure of H2O;

Let the pressure is 1 atm OR 760 torr.

As H2 is collected over water, we have to consider the vapor pressure of H2O as well.

Using data i.e. vapor pressure of H2O at 40° C = 55.365 torr

So, pressure of H2 = P = 760 - 55.365 = 704.635 torr = 704.635/760 = 0.9272 atm

Volume of H2 = 80 ml = 0.08 liter

Temperature (T) = 40 + 273 = 313 K

Gas constant (R) = 0.0821 L atm/mol K

Let n is moles of H2. Applying ideal gas equation;

PV = nRT

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

n = 0.00289 moles

Mass of H2 = moles * molar mass = 0.00289 * 2.016 = 0.00582 grams

OR 5.8*10^-3 grams ...Answer

----> Case 2) When we don't consider vapor pressure;

Pressure of H2 = 1 atm, all other parameters will remain same as in case 1.

So, mass of H2 = 6.3*10^-3 grams

But Case 1) is correct approach as in question it is mentioned that H2 is collected over water.

You might be interested in
Explain what a chemical reaction is and moles
Delvig [45]

Answer:

A process during which chemical bonds between atoms are broken and new ones are formed, producing one or more substances.

Moles are the amount of substance that contains as many particles.

Explanation:

A chemical reaction is when a chemical change occurs for example when a nail comes into contact with air and is then exposed to air it begins to rust. It forms a red-brown substance which changes the chemical composition of the original compound.

Examples of chemical reactions:

Combustion

Oxidation (rusting)

Cooking an egg

Photosynthesis

Digestion

Fireworks

Paper Burnin

The mole is the amount of substance that contains as many particles (molecules, ions or atoms) as there are in 12g of carbon.

1 mol is the amount of substance that contains the same number of particles as there are atoms in 12.0 g of carbon-12 and that number is referred to as Avogardo's constant (6.022 x 10^{23}).

3 0
2 years ago
Find the natural abundance of Si-30.
nataly862011 [7]
<span> First you need to know how many isotopes there are of silicon, and its average atomic units (look at periodic table). Then make up a system of equations to solve for it. Theres 3 stable silicon isotopes (28, 29, 30) so you will need to have 3 equations. You must be given the percent abundance of at least one of the isotopes to solve because here I can only see 2 equations (numbered down below) set x = percent abundance of si-28 y = percent abundance of si-29 z = percent abundance of si-30 since all of silicon atoms account for 100% of all silicon: x + y + z = 100% = 1 therefore: 1) x = 1 - y - z You also have 2) 28x + 29y + 30z = average atomic mass you can substitute x so that equation becomes: 28 (1 - y - z) + 29y + 30z = average atomic mass See how you have 2 variables here? You cant go on until you know the value of one isotope already or you have given a clue which you can derive the third equation</span>
5 0
3 years ago
What is the atomic mass?
labwork [276]

Answer:

Sonic has your answer The atomic mass is the mass of an atom. Although the SI unit of mass is kilogram, the atomic mass is often expressed in the non-SI unit dalton where 1 dalton is defined as ¹⁄₁₂ of the mass of a single carbon-12 atom, at res

8 0
3 years ago
An Expert, please answer this question!
Rudiy27

Answer:

C) The student and desk have to be in contact to apply the force.

Explanation:

I am pretty sure :)

3 0
2 years ago
Read 2 more answers
2. What effect does adding a neutron have on the atom’s mass?
anyanavicka [17]
It does<span>, however, change the </span>mass<span> of the nucleus. </span>Adding<span> or removing </span>neutrons<span>from the nucleus are how isotopes are created. Protons carry a positive electrical charge and they alone determine the charge of the nucleus.</span>
7 0
2 years ago
Other questions:
  • You have just performed a laboratory activity where a lot of chemical waste was produced. all of the chemical wastes should be
    13·2 answers
  • What is the main difference between scholarly research and scientific research? Scientists wear white coats. One is performed wh
    15·2 answers
  • The periodic table tells you how many grams are in a mole of atoms of any
    11·1 answer
  • If 2.0 moles of A and 3.0 moles of B react according to the hypothetical reaction below, how many moles of the excess reactant w
    9·2 answers
  • Need to fill in blank with choice above
    6·1 answer
  • Which factor affects gravitational potential energy but not elastic potential energy?
    13·1 answer
  • Question 15 need this answered asap (chemistry)
    12·1 answer
  • The molar heat of vaporization of water is 40.7kJ/mol. How much heat must be absorbed to convert 50.0 grams of liquid water at 1
    15·1 answer
  • Elements are classified into Pure Substances and Mixtures. <br><br> A. True <br> B. False
    7·1 answer
  • Which compounds have the empirical formula CH20?
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!