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ElenaW [278]
3 years ago
13

How many molecules of HBr are present in 42.5 grams of HBr

Chemistry
1 answer:
Anna71 [15]3 years ago
4 0
HBr molar mass is 80.9 g/mol
this means in 80.9 g - 1 mol of HBr
1 mol consists of 6.022 x 10²³ molecules of HBr
that means in 80.9 g HBr there are 6.022 x 10²³ molecules of HBr
therefore in 42.5 g of HBr there are 6.022 x 10²³/80.9 * 42.5 
the number of HBr molecules are therefore - 3.16 x 10²³ HBr molecules

You might be interested in
How many moles of KBr are present in 8.96 x 10^21
Gelneren [198K]

Answer:

0.015 moles

Explanation:

  • One mole of a compound contains molecules equivalent to the Avogadro's constant, 6.022 × 10^23.
  • That is, 1 mole of a compound will have 6.022 × 10^23 molecules.

In our case, We are given 8.96 x 10^21 molecules of KBr

We need to find the number of moles in 8.96 x 10^21 molecules

1 mole of KBr = 6.022 × 10^23 molecules.

8.96 x 10^21 molecules = ?

Therefore;

(1 × 8.96 x 10^21 molecules ) ÷ 6.022 × 10^23 molecules.

 = 1.488 × 10^-2 moles

 = 0.01488 moles

= 0.015 moles

6 0
3 years ago
A sample of methane occupies a volume of 370.0 ml at 25 oC and exerts a pressure of 1020 mm Hg. If the volume is allowed to expa
vagabundo [1.1K]

Answer:

744.9 mmHg ≅ 745 mmHg

Explanation:

The base to solve this, is the Ideal Gases Law. The mentioned formula is:

P . V = n . R . T

To compare two situations, we can propose:

For the first situation P₁ . V₁ = n₁. R . T₁

For the second situation P₂ . V₂ = n₂ . R . T₂

As the sample has the same moles and R is a constant value, we can avoid them so: (P₁ . V₁) / T₁ = (P₂ . V₂) / T₂

We need to make Tº unit conversion:

25ºC + 273 = 298K

We replace data → (370 mL . 1020 mmHg) / 298K = (P . 510 mL) / 300 K

(377400 mL.mmHg / 298K) . 300 K = P . 510 mL

379932.8 mL . mmHg = P . 510 mL

(379932.8 mL . mmHg) / 510 mL = P → 744.9 mmHg

7 0
3 years ago
I need help writing a LAB REPORT about NATURAL SELECTION
LekaFEV [45]

Answer:

Translate from Ukrainian.

У цей приклад я візьму селекції пшениці. Коли ми будемо говорити про селекцію цього злака, то ми можемо отримати меньшу собівартість, та вартість вирощування. Збільшена урожайність, та менша потреба в гербіцидах, пестицидах, та інсектицидах це теж наслідок. Тому селекція це майбутнє!

5 0
3 years ago
What is the molarity of 0.540g Mg N,0. in 250 mL of solution?​
Sati [7]

Answer:

2.16x10^-03

molarity=mass÷volume

0.540÷250

3 0
3 years ago
One atom of silicon can properly be combined in a compound with
aev [14]
B. two atoms of oxygen
3 0
3 years ago
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