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3 years ago

How did Mendeleev arrange the known elements?

Chemistry

2 answers:

Agata [3.3K]3 years ago

4 0

In order of relative atomic mass.

klemol [59]3 years ago

4 0

Mendeleev arranged elements in rows in increasing order according to their atomic number, while also grouping elements with similar chemical properties in columns.

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A combustion analysis of 5.214 g of a compound yields 5.34 g co 2 , 1.09 g h 2 o, and 1.70 g n 2 . if the molar mass of th

nekit [7.7K]

Answer is: C₃H₃N₃O₃.
Chemical reaction: CₓHₓNₓOₓ + O₂ → aCO₂ + x/2H₂ + x/2N₂.
m(CₐHₓNₓ) = 5,214 g.
m(CO₂) = 5,34 g.
m(H₂) = 1,09 g.
m(N₂) = 1,70 g.
n(CO₂) = n(C) = 5,34 g ÷ 44 g/mol = 0,121 mol.
n(H₂O) = 1,09 g ÷18 g/mol = 0,06 mol.
n(H) = 2 · 0,0605 mol = 0,121 mol.
n(N₂) = 1,7 g ÷ 28 g/mol = 0,0607 mol.
n(N) = 0,0607 mol · 2 = 0,121 mol.
n(C) : n(H) : n(N) = 0,121 mol : 0,121 mol : 0,121 mol /: 0,121
n(C) : n(H) : n(N) = 1 : 1 : 1.
M(CHN) = 27 g/mol.
m(O₂) = 8,13 g - 5,214 g = 2,914 g.
n(O₂) = 2,914 g ÷ 32 g/mol = 0,09 mol.
n(CₓHₓNₓOₓ) = 5,214 g ÷ 129,1 g/mol = 0,0404 mol.
n(CₓHₓNₓOₓ) : n(CO₂) = 1 : 3.

3 0

3 years ago

Read 2 more answers

- Equilibrium shifts for slightly soluble compounds The reaction for the formation of a saturated solution of silver bromide (Ag

RideAnS [48]

Answer:

1) Favor formation of reactant

2) Favor formation of product

3) Favor formation of product

4) Favor formation of product

5) Favor formation of product

Explanation:

The reaction is $AgBr(s)--->Ag^{+}(aq)+Br^{-}(aq)$

The reaction is endothermic

1. Adding hydrobromic acid (HBr)

It will increase the amount of bromide ion. Bromide ion is one of the product so it will favor formation of reactant.

2. Lowering the concentration of bromide (Br-) ions

As we are decreasing the the concentration of product it will favor formation of more products

3. Heating the concentrations

If we are heating the mixture, it will increase the temperature and it will favor endothermic reaction. Thus will favor formation of product.

4. Adding solid silver bromide (AgBr)

If we are adding silver bromide it means we are increasing the concentration of reactant, it will favor formation of products

5. Removing silver (Ag+) ions

Removing silver ions means we are decreasing the concentration of product thus it will favor formation of products.

3 0

3 years ago

What mass of zinc (molar mass 65.4 g moll) does it take to produce 0.50 mole of H2(g)?

Hatshy [7]

Answer:

32.7 g of Zn

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

Zn + 2HCl —> ZnCl₂ + H₂

From the balanced equation above,

1 mole of Zn reacted to produce 1 mole of H₂

Next, we shall determine the number of mole of Zn required to produce 0.5 mole of H₂. This can be obtained as follow:

From the balanced equation above,

1 mole of Zn reacted to produce 1 mole of H₂.

Therefore, 0.5 mole of Zn will also react to produce to 0.5 mole of H₂.

Thus, 0.5 mole of Zn is required.

Finally, we shall determine the mass of 0.5 mole of Zn. This can be obtained as follow:

Mole of Zn = 0.5 mole

Molar mass of Zn = 65.4 g/mol

Mass of Zn =?

Mass = mole × molar mass

Mass of Zn = 0.5 × 65.4

Mass of Zn = 32.7 g

Thus, 32.7 g of Zn is required to produce 0.5 mole of H₂.

4 0

2 years ago

What is the molarity of 3.0 L solution containing 250 g of Nal

IgorC [24]

Answer: C. 0.57 M

Explanation:

Molarity= Moles/Vol

8 0

3 years ago

Compound X has a molar mass of 316.25 g*mol^-1 and the following composition:

Leokris [45]

Answer:

Compound X has a molar mass of 316.25 g*mol^-1 and the following composition:

element & mass %

phosphorus & 39.18%

sulfur & 60.82%

Write the molecular formula of X.

Explanation:

The given molecule of phosphorus and sulfur has molar mass --- 316.25 g.

Empirical formula calculation:

element: phosphorus sulfur

co9mposition: 39.185% 60.82%

divide with

atomic mass: 39.185/31.0 g/mol 60.82/32.0g/mol

=1.26mol 1.90mol

smallest mole ratio: 1.26mol/1.26mol =1 1.90mol/1.26 mol =1.50

multiply with 2: 2 3

Hence, the empirical formula is:

P2S3.

Mass of empirical formula is:

158.0g/mol

Given, molecule has molar mass --- 316.25 g/mol

Hence, the ratio is:

316.25g/mol/158.0 =2

Hence, the molecular formula of the compound is :

2 x (P2S3)

= $P_4S_6$

8 0

3 years ago