Which of the following reactions involves two or more substances combining to form a new compound?

What kind of reaction is AgNO3+KI —> AgI+KNO3?

Scilla [17]

Answer:

Substitution reaction

5 0

3 years ago

A student decomposed 3.67g of copper (ii) hydroxide into copper (ii) oxide. how many ml of 3m h2so4 is need to react with all th

vredina [299]

In the presence of heat, copper (II) hydroxide decomposes in to copper (II) oxide.
Cu(OH)₂ (s) ----> CuO (s) + H₂O (l)
upon decomposition, water is removed from Cu(OH)₂
the amount of Cu(OH)₂ decomposed - 3.67 g
number of moles of Cu(OH)₂ - 3.67 g / 97.5 g/mol = 0.038 mol
stoichiometry of Cu(OH)₂ to CuO is 1:1
therefore number of CuO moles formed are - 0.038 mol
CuO reacts with sulfuric acid to form CuSO₄
CuO + H₂SO₄ ---> CuSO₄ + H₂O
stoichiometry of CuO to H₂SO₄ is 1:1
therefore number of H₂SO₄ moles that should react is 0.038 mol
the molarity of H₂SO₄ is 3M
this means that in 1000 ml - 3 mol of H₂SO₄ present
so if 3 mol are present in 1000 ml
then volume for 0.038 mol = 1000/3 * 0.038
= 12.67 ml

6 0

3 years ago

The table below provides some information about an unidentified element. Based on this information, the unidentified element is

Leona [35]

In the physical properties, it is mentioned that the element has 4 valence electrons. The elements in the periodic table are arranged such that, the number of valence electrons present in the neutral atoms belonging to a particular group is equal to the group number.

Thus, the unidentified element can be best classified as a nonmetal in period 4

Ans C)

5 0

3 years ago

Help me answer this chemistry question. thank you!

tatiyna

Answer:

78.85

Explanation:

To calculate the average atomic mass of the isotopes we use the given masses and abundances, as follows:

Mass of Isotope 1 * Abundance of Isotope 1 + Mass of Isotope 2 * Abundance of Isotope 2 + ....

In other words:

78 amu * 75/100 + 81 amu * 15/100 + 82 amu * 10/100 = 78.85

So the answer is 78.85.

8 0

2 years ago

A certain amount of H2S was added to a 2.0 L flask and allowed to come to equilibrium. At equilibrium, 0.072 mol of H2 was found

SIZIF [17.4K]

Answer:

0.098 moles H₂S

Explanation:

The reaction that takes place is

2H₂(g) + S₂(g) ⇄ 2H₂S(g) keq = 7.5

We can express the equilibrium constant as:

keq = [H₂S]² / [S₂] [H₂]² = 7.5

With the volume we can calculate the equilibrium concentration of H₂:

[H₂] = 0.072 mol / 2.0 L = 0.036 M

The stoichiometric ratio tells us that the concentration of S₂ is half of the concentration of H₂:

[S₂] = [H₂] / 2 = 0.036 M / 2 = 0.018 M

Now we can calculate [H₂S]:

7.5 = [H₂S]² / (0.018*0.036²)

[H₂S] = 0.013 M

So 0.013 M is the concentration of H₂S at equilibrium.

This would amount to (0.013 M * 2.0 L) 0.026 moles of H₂S

The moles of H₂ at equilibrium are equal to the moles of H₂S that reacted.

Initial moles of H₂S - Moles of H₂S that reacted into H₂ = Moles of H₂S at equilibrium

Initial moles of H₂S - 0.072 mol = 0.026 mol

Initial moles of H₂S = 0.098 moles H₂S

8 0

3 years ago