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2 years ago

Chemical Equations and Reactions WS

Chemistry

1 answer:

ruslelena [56]2 years ago

7 0

Answer:

1,1,1

decomposition reaction

Explanation:

The reaction equation is given as:

_Ca(OH)₂ → _CaO + _H₂O

This reaction is a decomposition reaction in which a single reactant breaks down to give two or more products.

To balance the equation, we assign variables a, b and c, then we use a mathematical approach to solve the problem;

aCa(OH)₂ → bCaO + cH₂O

Conserving Ca : a = b

O: 2a = b + c

H: 2a = 2c

let a = 1, b = 1 , c = 1

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What was the initial volume of the hydrogen in cm3?

svetlana [45]

Answer:

255.51cm3

Explanation:

Data obtained from the question include:

V1 (initial volume) =?

T1 (initial temperature) = 50°C = 50 + 273 = 323K

T2 (final temperature) = - 5°C = - 5 + 237 = 268K

V2 (final volume) = 212cm3

Using the Charles' law equation V1/T1 = V2/T2, the initial volume of the gas can be obtained as follow:

V1/T1 = V2/T2

V1/323 = 212/268

Cross multiply to express in linear form

V1 x 268 = 323 x 212

Divide both side by 268

V1 = (323 x 212)/268

V1 = 255.51cm3

Therefore, the initial volume of the gas is 255.51cm3

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3 years ago

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omeli [17]

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3 years ago

Classify these substances? More than one answer may apply in each case.

dalvyx [7]

Answer:

N2 element, pure substance

O2 element, pure substance

N2O Compound, pure substance

Air (mostly N2 and O2 ) homogeneous mixture

Explanation:

N2, Nitrogen is known as the chemical element that is characterized by having atomic number 7 and that is symbolized by the letter N, in its molecular version, it is recognized as N2.

O2, Oxygen is the chemical element of atomic number 8, this molecular form is composed of two atoms of this element.

A chemical element is a type of matter, consisting of atoms of the same class.

N2O, Nitrous oxide is formed by the union of two molecules of nitrogen and one of oxygen, which is considered a chemical compound since it is a substance formed by the chemical combination of two different elements of the periodic table.

A pure substance is one that cannot change state or divide into other substances, except for a chemical reaction.

Air (mostly N2 and O2 ), it is a homogeneous mixture of gases that constitutes the earth's atmosphere. A homogeneous mixture is a type of mixture in which its components are not distinguished and in which the composition is uniform and each part of the solution has the same properties.

3 0

3 years ago

Write the balanced equation for a reaction between aqueous nitric acid (HNO3) and solid lithium metal (this is a single replacem

Lemur [1.5K]

Answer: The equation is given below.

Explanation:

Single replacement reactions are the chemical reactions in which more reactive metal displaces a less reactive metal from its chemical reaction. General equation for these reactions is given by the equation:

$A+BC\rightarrow AC+B$

Metal A is more reactive than metal B.

The reactivity of metals is judged with the help of reactivity series. In this series, the metals lying above are more reactive than the metals which lie below in the series.

For the reaction of solid lithium metal and nitric acid, the equation follows:

$3Li(s)+4HNO_3(aq.)\rightarrow 3LiNO_3(aq.)+2H_2O(l)+NO(g)$

This is a type of single replacement reaction because Lithium (more reactive metal) is replacing Hydrogen (less reactive metal) from the chemical reaction.

3 0

3 years ago

Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s) + H2O (l) â†’ Ca(OH)2 (s) In a p

dybincka [34]

Answer:

The option closest to the percentage yield is option;

d. 81.1

Explanation:

The given chemical equation of the reaction is presented as follows;

CaO (s) + H₂O (l) → Ca(OH)₂

The mass of CaO in the experiment, m = 2.00 g

The volume of water with which the CaO was reacted = Excess volume of water

Number of moles = Mass/(Molar mass)

The mass of Ca(OH)₂ recovered, actual yield = 2.14 g

The molar mass of CaO = 56.0774 g/mol

The number of moles of CaO in the reaction, n₁ = 2.00 g/(56.0774 g/mol ≈ 0.036 moles

The molar mass of Ca(OH)₂ = 74.093 g/mol

The number of moles of Ca(OH)₂ in the reaction, n₂ = 2.14 g/(74.093 g/mol) ≈ 0.029 moles

From the given chemical reaction, one mole of CaO reacts with one mole of H₂O to produce one mole of Ca(OH)₂

Therefore, 0.036 moles of CaO will produce 0.036 moles of Ca(OH)₂

Mass = Number of moles × Molar mass

The mass of 0.036 moles of Ca(OH)₂ ≈ 0.036 moles × 74.093 g/mol = 2.667348 grams

∴ The theoretical yield of Ca(OH)₂ = 2.667348 grams

$Percentage \ yield = \dfrac{Actual \ yield}{Theoretical \ yield} \times 100 \%$

The percentage yield = (2.14 g)/(2.667348 grams) × 100 = 80.23%

Therefore, the option which is closest is option d. 81.1.

5 0

3 years ago