PLEASE HELP Which is a true of a molecule? Quesion 3 PLEASE HELP

Alisiya [41]

Out of the five major mass extinction, one is Cretaceous-Tertiary extinction (K-T extinction). It happened 66 million years ago marked by the end of the Cretinous period.

4 0

3 years ago

Oxygen gas can be prepared by heating potassium chlorate according to the following equation: 2KClO3(s)2KCl(s) + 3O2(g) The prod

Ipatiy [6.2K]

Answer:

The number of moles of KClO₃ reacted was 0,15 mol

Explanation:

For the reaction:

2KClO₃(s) → 2KCl(s) + 2O₂(g)

The only gas product is O₂.

Total pressure is the sum of vapor pressure of water with O₂ gas formed. Thus, pressure of O₂ is:

749mmHg - 23,8mmHg = 725,2mmHg

Using gas law:

PV/RT = n

Where:

P is pressure (725,2mmHg ≡ 0,9542atm)

V is volume (5,76L)

R is gas constant (0,082 atmL/molK)

And T is temperature (25°C ≡ 298,15K)

Replacing, number of moles of O₂ are 0,2248 moles

As 2 moles of KClO₃ react with 3 moles of O₂ the moles of KClO₃ that reacted was:

0,2248 mol O₂× $\frac{2 mol KClO_{3}}{3 mol O_{2}}$ = 0,15 mol of KClO₃

I hope it helps!

8 0

3 years ago

Consider the following scenario

GarryVolchara [31]

Answer:

See explaination

Explanation:

Going by the clues that it is between Silver Flouride (AgF) and Sodium Fluoride (NaF) and since it is an aqueous solution , the 1 liter bottle is likely to be Sodium Chloride( NaCl). Going by the reaction,

AgF + NaCl= AgCl + NaF

Here, the color of AgCl is white, hence the solution cannot be AgCl.

Determination of NaCl

Determination of NaCl can be done by Mohr's Method or Volhard's method. But results in Volhard's method are more accurate . Its uses the method of back titration with Potassium Thiocynate which forms a AgCl precipitate . Prior to titration,excess AgNO3 ( The problem also has a clue that excess reagents are present in the lab ) is added to the NaCl solution so that all the Cl- ions react with Ag+. Fe3+ is then added as an indicator and the solution is titrated with KSCN to form a silver thiocyannite precipitate (AgSCN). Once all the silver has reacted, a slight excess of SCN- reacts with Fe3+ to form Fe(SCN)3 dark red complex. The concentration of Cl- is determined by subtracting the titer findings of Ag+ ions that reacted to form AgSCN from the Ag NO3 moles added to the solution. This is used because pH of the solution is acidic. If the pH of solution is basic, Mohr's method is used.

Reactions

Ag+ (aq)+ Cl-(aq) = AgCl(aq)

Ag+(aq) + SCN-(aq) = AgSCN(aq)

Fe3+(aq) + SCN-(aq) = [FeSCN]2- (aq)

7 0

3 years ago

What is conductivity?

r-ruslan [8.4K]

The degree to which a specified material conducts electricity, calculated as the ratio of the card density in the material to the electric field that causes the flow of current. It is the reciprocal of the resistivity.

5 0

3 years ago

Read 2 more answers

Find the pH of a solution whose H concentration is 0.7 x 10-3.

dexar [7]

Answer: pH = 3.15

Explanation: Solved in the attached picture.

6 0

3 years ago