Chapter 3 reactivity of metals mcq question and question and answer and important notes?

What mass (in g) of potassium chlorate is decomposed if the yield of oxygen gas for the first reaction is 88.6%, if it is known

Ainat [17]

Using the stoichiometry and the number of moles involved in the reaction, The mass of KClO3 decomposed is 63.73 g.

Let us take it up from the second reaction;

Using stoichiometry , the equation of the reaction is;

CH4 + 2O2 ⟶ CO2 + 2H2O

Number of moles of CO2 produced = mass/molar mass

Actual yield of CO2 = 23.6 * 100/77.8 = 30.33 g

Number of moles in 30.33 g of CO2 = 30.33 g/44 g/mol = 0.69 moles

From the reaction equation;

2 moles of O2 yields 1 mole of CO2

x moles of O2 yields 0.69 moles of CO2

x = 2 * 0.69 /1

x = 1.38 moles of O2.

Mass of O2 used = 1.38 moles * 32 g/mol = 44.16 g

This becomes the actual yield of the first reaction.

Theoretical yield of oxygen = 44.16 g * 100/88.6

= 49.84 g of O2

Number of moles of O2 = 49.84 g/32 g/mol = 1.56 moles

Given the reaction equation;

KClO3 ⟶ 2KCl + 3O2

1 mole of KClO3 yields 3 moles of O2

x moles of O2 yields 1.56 moles of O2

x = 1 * 1.56/3

= 0.52 moles of KClO3

Mass of KClO3 decomposed = 0.52 moles * 122.55 g/mol = 63.73 g of KClO3

Learn more: brainly.com/question/9743981

7 0

2 years ago

How many moles of magnesium chloride can be formed from 4.86 g of Mg and 21.27 g of Cl2?

Hoochie [10]

Answer:

Moles of magnesium chloride can be produced are 0.2 moles

Explanation:

The reaction of Mg with Cl2 is:

Mg + Cl₂ → MgCl₂

Where 1 mole of Mg reacts per mole of Cl₂ to produce MgCl₂.

As the reaction is 1:1, we need to convert the mass of both Mg and Cl₂ to moles. The lower number of moles will determine the moles of MgCl₂ that will be produced:

Moles Mg -Molar mass: 24.3g/mol-:

4.86g * (1mol / 24.3g) = 0.2 moles Mg

Moles Cl₂ -Molar mass: 24.3g/mol-:

21.27g * (1mol / 70.9g) = 0.3 moles Cl₂

As moles of Mg < moles of Cl₂, Mg is limiting reactant and moles of magnesium chloride can be produced are 0.2 moles

8 0

3 years ago

Compute the molar enthalpy of combustion of glucose (C6 H12O6 ): C6 H12O6 (s) + 6 O2 (g) → 6 CO2 (g) + 6 H2 O (g) Given that com

lana66690 [7]

Answer:

The molar enthalpy of combustion of glucose is -2819.3 kJ/mol

Explanation:

Step 1: Data given

Mass of glucose = 0.305 grams

Combustion of 0.305 grams causes a raise of 6.30 °C

Calorimeter has a heat capacity of 755 J/°C

Molar mass of glucose = 180.2 g/mol

Step 2: The balanced equation

C6H12O6 (s) + 6O2 (g) → 6CO2 (g) + 6H2O (g)

Step 3:

ΔH = (m * C * ΔT + c(calorimeter) * ΔT)

with m = mass of the solutin = 0.305 grams

with C = heat capacity of water = 4.184 J/g°C

with ΔT = the change in temperature = 6.30 °C

with c(calorimeter) = 755 J/°C

ΔH = 0.305 * 4.184 *6.30 + 755 * 6.30 = 4764.5 J ( negative because it's exothermic)

Step 4: Calculate moles of glucose

Moles glucose = mass glucose / Molar mass glucose

Moles glucose = 0.305 grams / 180.2 g/mol

Moles glucose = 0.00169 moles

Step 5: Calculate molar enthalpy

Molar enthalpy = -4764.5 J / 0.00169 moles

Molar enthalpy = - 2819254.2 J/moles = -2819.3 kJ/moles

The molar enthalpy of combustion of glucose is -2819.3 kJ/mol

5 0

3 years ago

Give the complete ionic equation for the reaction (if any) that occurs when aqueous solutions of MgSO3 and HI are mixed. Give th

Sunny_sXe [5.5K]

Answer:

Mg²⁺(aq) + SO₃²⁻(aq) + 2 H⁺(aq) + 2 I⁻(aq) ⇄ Mg²⁺(aq) + 2I⁻(aq) + H₂O(l) + SO₂(g)

Explanation:

Give the complete ionic equation for the reaction (if any) that occurs when aqueous solutions of MgSO₃ and HI are mixed.

When MgSO₃ reacts with HI they experience a double displacement reaction, in which the cations and anions of each compound are exchanged, forming H₂SO₃ and MgI₂. At the same time, H₂SO₃ tends to decompose to H₂O and SO₂. The complete molecular equation is:

MgSO₃(aq) + 2 HI(aq) ⇄ MgI₂(aq) + H₂O(l) + SO₂(g)

In the complete ionic equation, species with ionic bonds dissociate into ions.

Mg²⁺(aq) + SO₃²⁻(aq) + 2 H⁺(aq) + 2 I⁻(aq) ⇄ Mg²⁺(aq) + 2I⁻(aq) + H₂O(l) + SO₂(g)

6 0

3 years ago

Balance the equation below Fe, Fe+ 02

Katena32 [7]

2 Fe2O5-> 4 Fe+ 5 O2

5 0

2 years ago

Chapter 3 reactivity of metals mcq question and question and answer and important notes? ​

Chapter 3 reactivity of metals mcq question and question and answer and important notes?