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3 years ago

What's the preview of the scientific method

Chemistry

1 answer:

Dafna11 [192]3 years ago

5 0

Explanation:

overall preview would be an expirement is an empirical procedure that arbitrates competing models or hypothesis ☺️

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How many moles of Mg(OH)2 will react with 2.5 mol HCI?

bekas [8.4K]

Answer:

1.25mole of Mg(OH)₂

Explanation:

The reaction is between Mg(OH)₂ and HCl, this is a neutralization reaction between an acid and a base.

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

The balanced reaction equation is given above.

2 mole of HCl reacts with 1 mole of Mg(OH)₂

So, 2.5mole of HCl will react with $\frac{2.5}{2}$ = 1.25mole of Mg(OH)₂

The number of moles of Mg(OH)₂ is given as 1.25mol

5 0

3 years ago

What is the empirical formula for a compound if a sample contains 3.72 g of P and 21.28 g of Cl

fenix001 [56]

M(P)=3.72 g
M(P)=31 g/mol

m(Cl)=21.28 g
M(Cl)=35.5 g/mol

n(P)=m(P)/M(P)
n(P)=3.72/31=0.12 mol

n(Cl)=m(Cl)/M(Cl)
n(Cl)=21.28/35.5=0.60 mol

P : Cl = 0.12 : 0.60 = 1 : 5

PCl₅ - is the empirical formula

6 0

3 years ago

according to the kinetic molecular theory the pressure exerted by a sample of gas at constats volume doubles when the absolute t

ozzi

Answer: gas molecules will hit the container walls more frequently and with greater force

Explanation:

According to the postulates of kinetic molecular theory:

1. The pressure exerted by a gas in a container results from collisions between the gas molecules and the container walls.

2. The average kinetic energy of the gas molecules is proportional to the kelvin temperature of the gas.

When the temperature is increased, so the average kinetic energy and the rms speed also increase. This means that the gas molecules will hit the container walls more frequently and with greater force because they are all moving faster. This increase the pressure.

7 0

3 years ago

Consider the reaction given below.

Drupady [299]

Answer:

K = 0.167 s⁻¹

Explanation:

1) Rate law, at a given temperature:

Since all the data are obtained at the same temperature, the equilibrium constant is the same.

Since only reactants A and B participate in the reaction, you assume that the form of the rate law is:

r = K [A]ᵃ [B]ᵇ

2) Use the data from the table

Since the first and second set of data have the same concentration of the reactant A, you can use them to find the exponent b:

r₁ = (1.50)ᵃ (1.50)ᵇ = 2.50 × 10⁻¹ M/s

r₂ = (1.50)ᵃ (2.50)ᵇ = 2.50 × 10⁻¹ M/s

Divide r₂ by r₁: [ 2.50 / 1.50] ᵇ = 1 ⇒ b = 0

Use the first and second set of data to find the exponent a:

r₁ = (1.50)ᵃ (1.50)ᵇ = 2.50 × 10⁻¹ M/s

r₃ = (3.00)ᵃ (1.50)ᵇ = 5.00 × 10⁻¹ M/s

Divide r₃ by r₂: [3.00 / 1.50]ᵃ = [5.00 / 2.50]

2ᵃ = 2 ⇒ a = 1

3) Write the rate law

r = K [A]¹ [B]⁰ = K[A]

This means, that the rate is independent of reactant B and is of first order respect reactant A.

4) Use any set of data to find K

With the first set of data

r = K (1.50 M) = 2.50 × 10⁻¹ M/s ⇒ K = 0.250 M/s / 1.50 M = 0.167 s⁻¹

Result: the rate constant is K = 0.167 s⁻¹

6 0

4 years ago

Two common methods to generate an aldehyde is by oxidation of an alcohol and through ozonolysis.

kotykmax [81]

Answer:

a. True.

Explanation:

Only primary and secondary alcohols can oxidise to give an aldehyde. But a weak oxidizing agent must be used to prevent formation of a carboxylic acid or ketone.

weak oxidizing agents: Chromyl chloride, silver/oxygen/500°C

take an example of ethanol:

 ${ \bf{CH _{3} CH_{2}OH \: \: \frac{Ag/O_{2} }{500 \degree C} > \: \:CH _{3} CHO}}$ 

 ${ \sf{CH _{3} CHO \: \: is \: ethanal}}$ 

By ozonolysis:

Here, reactants are Ozone gas, Carbon tetrachloride at a temperature (<20°C), ethanoic acid, zinc and water.

take an example of propanol:

if it undergoes ozonolysis, it gives ethanal and methanal.

5 0

3 years ago

Read 2 more answers