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3 years ago

When fe(no3)2(aq) and na2s(aq) are mixed, what is the black coloured precipitate that forms?

1 answer:

7 0

The black coloured precipitate that form is IRON ll SULPHIDE, FeS.
Iron sulphide ll sulphide is black in colour and is insoluble in water. It possess very high melting temperature and react in acids. Iron ll sulphide is used as pigment in hair dyes, glasses, bottles and paints. It is also used as lubricant.

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There are two common oxides of copper; one is 80% copper and the other is 89% copper by weight. Calculate the formula and name e

irakobra [83]

80% copper (Cu)

Cu: 80 : 63.546 = 1.259

O: 20 : 16 = 1.25

Cu:O = 1 : 1

the formula: CuO

89% copper (Cu)

Cu: 89 : 63.546 = 1.4

O: 11 : 16 = 0.6875

Cu:O = 2:1

the formula: Cu₂O

8 0

2 years ago

Which of the following is true about homogeneous mixtures? A. They are known as solutions

Helga [31]

Answer:

A is your answer..... !!!!!!!!!!!!!

7 0

3 years ago

Read 2 more answers

For the reaction CO2(g) + H2(g)CO(g) + H20(g)

Studentka2010 [4]

Answer:

The ΔG° is 29 kJ and the reaction is favored towards reactant.

Explanation:

Based on the given information, the ΔH°rxn or enthalpy change is 41.2 kJ, the ΔS°rxn or change in entropy is 42.1 J/K or 42.1 * 10⁻³ kJ/K. The temperature given is 289 K. Now the Gibbs Free energy change can be calculated by using the formula,

ΔG° = ΔH°rxn - TΔS°rxn

= 41.2 kJ - 289 K × 42.1 × 10⁻³ kJ/K

= 41.2 kJ - 12.2 kJ

= 29 kJ

As ΔG° of the reaction is positive, therefore, the reaction is favored towards reactant.

5 0

2 years ago

How does increasing the temperature affect a reaction?

Luden [163]

Answer:A. An increase in temperature increases the reaction rate.

Explanation:because of the disproportionately large increase in the number of high energy collisions. It is only these collisions (possessing at least the activation energy for the reaction) which result in a reaction.

4 0

3 years ago

Lead(II) oxide from an ore can be reduced to elemental lead by heating in a furnace with carbon. Calculate the expected yield of

Lelu [443]

Answer:

53kg is the expected yield of lead

Explanation:

Firstly, in order to solve this question, we need to write the equation of reaction correctly. This is as follows:

PbO(s) + C(s) ---> Pb(l) + CO(g)

We proceed from here. We should get the limiting reactant but this can only be obtained by getting the number of moles of each reactant present.

The formula to use across all boards is that the number of moles is the mass of each of the reactant divided by the molar mass of each of the reactant.

For PBO, mass is 57kg = 57000g

Molar mass of PBO = 223.20g/mol

The number of moles is thus 57,000/223.2 = 255.37 moles

For carbon, mass is also 57kg = 57000g

Molar mass is 12g/mol

Number of moles of carbon = 57000/12 = 4750 moles

From the number of moles, we can see that the number of moles of Carbon is greater than that of PbO. This means that PbO is the limiting reagent.

Hence we use it to calculate percentage yield.

The number of moles of lead formed is the same of number of moles of lead oxide = 255.37 since we have mole ratio of 1 to 1

The molar mass of lead is 207.20g/mol

The mass of lead formed is = moles of lead formed * molar mass of lead = 207.20 * 255.37 = 52,912g which is approximately 53kg

Hence the expected yield is 53kg

6 0

3 years ago