Which of the following is not one of the main five types of reactions?

Alex saw a rusty old car in an abandoned lot. Because he had recently read about chemical reactions, he began to wonder how the

Mice21 [21]

The answere is A .......

8 0

3 years ago

if you are using 657.0 grams of oxygen gas to react with calcium how many gram of calcium oxide will u product

DochEvi [55]

Answer:

The amount in grams of CaO that will be produced is 2,302.67824 grams

Explanation:

The reaction between calcium and oxygen to produce calcium oxide (quicklime) can be presented as follows;

2Ca (s) + O₂ (g) → 2CaO (s)

From the above chemical equation, we have;

2 moles of calcium, Ca, react with 1 mole of oxygen gas, O₂, to produce 2 moles of CaO

With the assumption that there is an excess amount of Ca, we have;

The molar mass of O₂ = 32 g/mol

The number of moles, 'n', of O₂ in 657.0 grams of oxygen is therefore;

The number of moles of a substance = Mass of substance/(Molar mass of substance)

∴ n = 657.0 g/(32 g/mol) = 20.53125 moles

The number of moles of O₂ in the 657.0 grams of oxygen present in the reaction, n = 20.53125 moles

1 mole of O₂ produces 2 moles of CaO, therefore, 20.53125 moles of oxygen will produce 2 × 20.53125 or 41.0625 moles of CaO

The molar mass of CaO = 56.0774 g/mol

Therefore, the mass of 41.0625 moles of CaO is given as follows;

Mass of substance = (The number of moles of a substance) × (Molar mass of substance)

The mass of CaO produced = 41.0625 moles × 56.0774 g/mol = 2,302.67824 g.

3 0

3 years ago

A certain liquid X has a normal boiling point of 133.60°C and a boiling point elevation constant Kb= 2.46°C kg mol^-1.Calculate

Afina-wow [57]

Answer:

136.63 °C

Explanation:

ΔTb=Tb solution - Tb pure

Where; Tb pure = 133.60°C

molar mass of solute = 121.14 g/mol

number of moles of solute; 52.2g/121.14 g/mol = 0.431 moles

molality = 0.431 moles/350 * 10^-3 = 1.23 molal

Then;

ΔTb = Kb * m * i

Kb = 2.46°C kg mol^-1

m = 1.23 molal

i = 1

ΔTb = 2.46 * 1.23 * 1

ΔTb = 3.03 °C

Hence;

Tb solution = ΔTb + Tb pure

Tb solution = 3.03 °C + 133.60°C

Tb solution = 136.63 °C

6 0

3 years ago

The percent yield of a chemical reaction is

Sergio039 [100]

Answer:

The correct choices are:

using accurate measurements

using pure chemicals

performing the reaction under the most ideal conditions

Explanation:

The theoretical yield is the maximum amount of product that could be obtained by the chemical reaction, from a given amount of reactants. You calculate the theoretical yield using the stoichiometry coefficients of the balanced chemical equation.

The percent yield is the ratio of the actual yield (the actual amount obtained) of a product to the theoretical yield for the same product, expressed as a percentage (i.e. multiplied by 100).

percent yield = actual yield × 100 / theoretical yield

As the actual yield decrease (the numerator of the ratio), the percent yield decrease.

To increase the percent yield it is important:

using accurate measurements

using pure chemicals

performing the reaction under the most ideal conditions

Using accurate measurements: if you do not add the correct amounts of each reactant, then the product obtained will not be what you can predict from the theoretical calculations and you will be wasteing one or other reactant, without reaching the maximum yield possible.

Using pure chemicals: if the chemicals are not pure, the amount of actual reactants will be lower than they should be, leading to a lower actual yield.

Performing the reaction under the most ideal conditions: the actual rate of reactions depend on the conditions: temperature and pressure are the most commons. Since, temperature and pressure may change that rate of reactions, you should find and use the most ideal conditions to get the greatest actual yield.

Adding water, can just dilute the reactants and would decrease the rate of reaction, which would not be helpful to increase the yield.

6 0

3 years ago

Read 2 more answers

as a gas occupied a volume of 250cc at 250at 700mm pressure temperature,25degree Celsius what additional pressure is required?re

Allisa [31]

Additional pressure required : 175 mm

<h3>Further explanation</h3>

Boyle's Law

At a constant temperature, the gas volume is inversely proportional to the pressure applied

$\rm p_1V_1=p_2.V_2\\\\\dfrac{p_1}{p_2}=\dfrac{V_2}{V_1}$