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WorksheetsChemical Reactions And Equation_LS_13
Total questions: 42
Worksheet time: 57mins
To show heating of lead nitrate is a decomposition reaction. What is the first statement of the video clip?
Take lead nitrate which is a white powder
in a test tube
and hold it in a tong
heat it over flame of burner
slowly as shown in diagram
pungent smelling brown fumes are evolved
and brownish residue is left
the chemical reaction is shown here: lead nitrate on heating decomposes to
lead monoxide
brown gas nitrogen dioxide that is NO2
and oxygen gases are evolved
To show heating of lead nitrate is a decomposition reaction. What is the second statement of the video clip?
it is an example of decomposition
reaction
heat it over flame of burner
slowly as shown in diagram
pungent smelling brown fumes are evolved
and brownish residue is left
the chemical reaction is shown here: lead nitrate on heating decomposes to
lead monoxide
brown gas nitrogen dioxide that is NO2
and oxygen gases are evolved
To show heating of lead nitrate is a decomposition reaction. What is the third statement of the video clip?
it is an example of decomposition
reaction
2Pb(NO3)2 +(heat)→2PbO+4NO2+O2
pungent smelling brown fumes are evolved
and brownish residue is left
the chemical reaction is shown here: lead nitrate on heating decomposes to
lead monoxide
brown gas nitrogen dioxide that is NO2
and oxygen gases are evolved
To show heating of lead nitrate is a decomposition reaction. What is the fourth statement of the video clip?
it is an example of decomposition
reaction
2Pb(NO3)2 +(heat)→2PbO+4NO2+O2
pungent smelling brown fumes are evolved
and brownish residue is left
the chemical reaction is shown here: lead nitrate on heating decomposes to
lead monoxide
brown gas nitrogen dioxide that is NO2
and oxygen gases are evolved
To show heating of lead nitrate is a decomposition reaction. What is the fifth statement of the video clip?
it is an example of decomposition
reaction
2Pb(NO3)2 +(heat)→2PbO+4NO2+O2
pungent smelling brown fumes are evolved
and brownish residue is left
the chemical reaction is shown here: lead nitrate on heating decomposes to
lead monoxide
brown gas nitrogen dioxide that is NO2
and oxygen gases are evolved
To show heating of lead nitrate is a decomposition reaction. What is the sixth statement of the video clip?
it is an example of decomposition
reaction
2Pb(NO3)2 +(heat)→2PbO+4NO2+O2
pungent smelling brown fumes are evolved
and brownish residue is left
the chemical reaction is shown here: lead nitrate on heating decomposes to
lead monoxide
brown gas nitrogen dioxide that is NO2
and oxygen gases are evolved
To show heating of lead nitrate is a decomposition reaction. State a well balanced equation for decomposition of Lead Nitrate
it is an example of decomposition
reaction
2Pb(NO3)2 +(heat)→2PbO+4NO2+O2
pungent smelling brown fumes are evolved
and brownish residue is left
the chemical reaction is shown here: lead nitrate on heating decomposes to
lead monoxide
brown gas nitrogen dioxide that is NO2
and oxygen gases are evolved
Cl2 + 2KI ——-> 2KCl + I2
Precipitation Reaction
2K + Cl2 ——–> 2KCl
Precipitation Reaction
In the following reaction between lead sulphide and hydrogen peroxide :
PbS (s) + 4H2O2 (aq) ————-> PbS04 (s) + 4H2O (l)
Which substance is reduced ?
H2O2 The oxidation number of O decreases from -1 to -2. Thus, O itself is reduced and acts as oxidising agent.
PbS. The oxidation number of S increases from -2 to +6. Thus, S itself is oxidised and acts as reducing agent.
Any species that is oxidised acts as reducing agent.
Any species that is reduced acts as oxidising agent.
In the following reaction between lead sulphide and hydrogen peroxide :
PbS (s) + 4H2O2 (aq) ————-> PbS04 (s) + 4H2O (l)
Which substance is oxidised ?
H2O2 The oxidation number of O decreases from -1 to -2. Thus, O itself is reduced and acts as oxidising agent.
PbS. The oxidation number of S increases from -2 to +6. Thus, S itself is oxidised and acts as reducing agent.
Any species that is oxidised acts as reducing agent.
Any species that is reduced acts as oxidising agent.
Identify the component oxidized in the following reaction and why? :
H2S + Cl2 ————->S + 2HCl
Oxidized substance: H2S
PbS. The oxidation number of S increases from -2 to +6. Thus, S itself is oxidised and acts as reducing agent.
By losing hydrogen atoms, H2S is oxidized to form to S.
Any species that is reduced acts as oxidising agent.
H2S + Cl2 = S + 2HCl, which substance is : Reduced.
Oxidized substance: H2S
By losing hydrogen atoms, H2S is oxidized to form to S.
Reduced substance: Cl2
By obtaining hydrogen atoms, Cl2 is reduced to HCl
H2S + Cl2 = S + 2HCl, which substance is : The oxidising agent
Reduced substance: Cl2
By obtaining hydrogen atoms, Cl2 is reduced to HCl
The oxidizing agent
Answer: Cl2
The reduced substance is called an oxidizing agent. Cl2 is, therefore, an oxidizing agent.
When SO2 gas is passed through saturated of H2S , the following reactions occur:
SO2+2H2S→2H2O+3S
In this reaction, which substance is oxidised?
H2S is oxidised to S.
SO2 is oxidised to S.
When SO2 gas is passed through saturated of H2S , the following reactions occur:
SO2+2H2S→2H2O+3S
In this reaction, which substance is reduced?
H2S is reduced to S.
SO2 is reduced to S.
The addition of oxygen to a substance is called …………(a)…………… whereas removal of oxygen is called ……(b)……
for a:
Oxidation
Reduction
Rancidity
Redox
The addition of oxygen to a substance is called …………(a)…………… whereas removal of oxygen is called ……(b)……
for b:
Oxidation
Reduction
Rancidity
Redox
The addition of hydrogen to a substance is called ……(a) … whereas removal of hydrogen is called ….(b)…
For a
Oxidation
Reduction
Rancidity
Redox
The addition of hydrogen to a substance is called ……(a) … whereas removal of hydrogen is called ….(b)…
For b
Oxidation
Reduction
Rancidity
Redox
Anti-oxidants are often added to fat containing foods to prevent………….. due to oxidation.
Corrosion
Rusting
Rancidity
Redox
What is an oxidation reaction? Identify in the following reaction: the substance oxidised
ZnO + C ———— > Zn + CO
C
ZnO
Zn
CO
What is an oxidation reaction? Identify in the following reaction: the substance reduced
ZnO + C ———— > Zn + CO
C
ZnO
Zn
CO
Redox reactions: What is the first statement of the video clip?
When magnesium combines with oxygen to form magnesium oxide
electrons on the magnesium atoms
are more strongly attracted to the oxygen atoms
than they are to their own nuclei.
So they swap over, creating two ions
The magnesium ions have an electrical charge of +2, because they've lost two electrons.
And the oxide ions have a charge of -2,
because they've gained two electrons.
Redox reactions: What is the second statement of the video clip?
Positive and negative charges attract,
so the ions bond to form a lattice.
electrons on the magnesium atoms
are more strongly attracted to the oxygen atoms
than they are to their own nuclei.
So they swap over, creating two ions
The magnesium ions have an electrical charge of +2, because they've lost two electrons.
And the oxide ions have a charge of -2,
because they've gained two electrons.
Redox reactions: What is the third statement of the video clip?
Positive and negative charges attract,
so the ions bond to form a lattice.
This is magnesium oxide, a white powder.
So they swap over, creating two ions
The magnesium ions have an electrical charge of +2, because they've lost two electrons.
And the oxide ions have a charge of -2,
because they've gained two electrons.
Redox reactions: What is the fourth statement of the video clip?
Positive and negative charges attract,
so the ions bond to form a lattice.
This is magnesium oxide, a white powder.
Oxidation is the loss of electrons.
The magnesium ions have an electrical charge of +2, because they've lost two electrons.
And the oxide ions have a charge of -2,
because they've gained two electrons.
Redox reactions: What is the fifth statement of the video clip?
Positive and negative charges attract,
so the ions bond to form a lattice.
This is magnesium oxide, a white powder.
Oxidation is the loss of electrons.
So in this reaction, the magnesium has been oxidized.
And the oxide ions have a charge of -2,
because they've gained two electrons.
Redox reactions: What is the sixth statement of the video clip?
Positive and negative charges attract,
so the ions bond to form a lattice.
This is magnesium oxide, a white powder.
Oxidation is the loss of electrons.
So in this reaction, the magnesium has been oxidized.
Historically, the only oxidation reactions
that scientists knew about all involved oxygen.
Redox reactions: What is the seventh statement of the video clip?
That's why they called them "oxidation reactions."
This is magnesium oxide, a white powder.
Oxidation is the loss of electrons.
So in this reaction, the magnesium has been oxidized.
Historically, the only oxidation reactions
that scientists knew about all involved oxygen.
Redox reactions: What is the eighth statement of the video clip?
That's why they called them "oxidation reactions."
But now we know plenty of oxidation reactions
that don't involve oxygen,
Oxidation is the loss of electrons.
So in this reaction, the magnesium has been oxidized.
Historically, the only oxidation reactions
that scientists knew about all involved oxygen.
Redox reactions: What is the ninth statement of the video clip?
That's why they called them "oxidation reactions."
But now we know plenty of oxidation reactions
that don't involve oxygen,
like the formation of lead trees
from zinc and lead nitrate solution.
So in this reaction, the magnesium has been oxidized.
Historically, the only oxidation reactions
that scientists knew about all involved oxygen.
Redox reactions: What is the tenth statement of the video clip?
That's why they called them "oxidation reactions."
But now we know plenty of oxidation reactions
that don't involve oxygen,
like the formation of lead trees
from zinc and lead nitrate solution.
The zinc atoms have no electrical charge.
Historically, the only oxidation reactions
that scientists knew about all involved oxygen.
Redox reactions: What is the tenth statement of the video clip?
That's why they called them "oxidation reactions."
But now we know plenty of oxidation reactions
that don't involve oxygen,
like the formation of lead trees
from zinc and lead nitrate solution.
The zinc atoms have no electrical charge.
Historically, the only oxidation reactions
that scientists knew about all involved oxygen.
Redox reactions: What is the eleventh statement of the video clip?
That's why they called them "oxidation reactions."
But now we know plenty of oxidation reactions
that don't involve oxygen,
like the formation of lead trees
from zinc and lead nitrate solution.
The zinc atoms have no electrical charge.
Lead nitrate solution, on the other hand,
consists of positively-charged lead ions and negatively-charged nitrate ions moving about in water.
Redox reactions: What is the twelfth statement of the video clip?
Zinc is more reactive than lead, which means it more readily gives up its electrons.
But now we know plenty of oxidation reactions
that don't involve oxygen,
like the formation of lead trees
from zinc and lead nitrate solution.
The zinc atoms have no electrical charge.
Lead nitrate solution, on the other hand,
consists of positively-charged lead ions and negatively-charged nitrate ions moving about in water.
Redox reactions: When magnesium combines with oxygen to form magnesium oxide, electrons on the magnesium atoms are more strongly attracted to the oxygen atoms than they are to their own nuclei. So they swap over, creating two ions. The magnesium ions have an electrical charge of +2, because they've lost two electrons.
In a redox reaction, which atoms are more attracted to oxygen atoms?
Hydrogen atoms
Magnesium atoms
Carbon atoms
Nitrogen atoms
What is the result of electrons swapping over in a redox reaction?
Formation of two ions
Formation of a covalent bond
Release of energy
Formation of a precipitate
What does magnesium combine with to form magnesium oxide?
Hydrogen
Carbon
Oxygen
Nitrogen
What is the charge of magnesium ions?
+1
+2
-1
-2
What is the charge due to losing two electrons?
+2
-2
+1
-1
What do redox reactions result in?
Molecules with different charges
Ions with the same charges
Atoms with different charges
Ions with different charges
What is involved in redox reactions?
Proton transfer
Electron transfer
Neutron transfer
Photon transfer
When magnesium combines with oxygen to form magnesium oxide, what happens to the electrons on the magnesium atoms?
They are more strongly attracted to the oxygen atoms than to their own nuclei.
In the reaction between magnesium and oxygen to form magnesium oxide, what happens to the electrons in the magnesium atoms?
a) They remain attracted to their own nuclei.
b) They are lost completely.
c) They become more attracted to the oxygen atoms.
d) Their attraction remains unchanged.
Why do magnesium ions have a charge of +2?
a) They gain two electrons.
b) They lose one electron.
c) They lose two electrons.
d) They gain two protons.
This reaction between magnesium and oxygen is an example of:
The magnesium ions have an electrical charge of +2, because they've lost two electrons and the oxide ions have a charge of -2, because they've gained two electrons. Positive and negative charges attract, so the ions bond to form a lattice. This is magnesium oxide, a white powder. Oxidation is the loss of electrons. So in this reaction, the magnesium has been oxidized. Historically, the only oxidation reactions that scientists knew about all involved oxygen.
What have historically been involved in known oxidation reactions?
Hydrogen
Nitrogen
Oxygen
Carbon
What is the main reason for ionic bonding?
Attraction between two neutral atoms
Repulsion between positively charged ions
Attraction between positively and negatively charged ions
Attraction between two negatively charged ions
What is the charge of magnesium ions?
+1
+2
-1
-2
What is the result of the oxidation reaction described?
Sodium chloride
Magnesium oxide
Potassium nitrate
Calcium carbonate
What is the result of the process described?
Formation of a stable compound
Formation of a volatile compound
Formation of a liquid compound
Formation of a gaseous compound
What phenomenon leads to the formation of a lattice in ionic bonding?
Repulsion of charges
Attraction of charges
Sharing of electrons
Absence of charges
What is involved in oxidation?
Gain of electrons
Loss of electrons
Sharing of electrons
Transfer of protons
Magnesium loses electrons in the reaction with oxygen.
What scientific term describes this process?
True or False: Oxidation only involves oxygen.
Positive and negative charges attract, so the ions bond to form a lattice. This is magnesium oxide, a white powder. Oxidation is the loss of electrons. That's why they called them "oxidation reactions." But now we know plenty of oxidation reactions that don't involve oxygen, like the formation of lead trees from zinc and lead nitrate solution. The zinc atoms have no electrical charge.
What color is magnesium oxide?
White
Black
Red
Blue
Why do ions bond to form a lattice?
Because they repel each other
Because they have similar charges
Because positive and negative charges attract
Because they are neutral
Can oxidation reactions occur without oxygen?
Yes
No
Sometimes
Depends on the reaction
What is oxidation?
Gain of electrons
Loss of electrons
Sharing of electrons
Transfer of protons
What can lead trees form from?
Copper and lead nitrate solution
Zinc and lead nitrate solution
Iron and lead nitrate solution
Aluminum and lead nitrate solution
Do zinc atoms have an electrical charge?
Yes
No
Sometimes
Depends
In the formation of magnesium oxide, why do ions bond to form a lattice structure?
Due to the attraction between positive and negative charges.
In the formation of magnesium oxide, what force attracts the magnesium and oxide ions to form a stable structure?
Ionic bonding (due to opposite charges)
The term "oxidation" historically referred to reactions involving oxygen. What is the modern understanding of oxidation?
It describes the loss of electrons from an atom or ion.
The passage mentions the formation of "lead trees" from zinc and lead nitrate. What property of zinc is relevant to this reaction?
But now we know plenty of oxidation reactions that don't involve oxygen, like the formation of lead trees from zinc and lead nitrate solution. The zinc atoms have no electrical charge. Lead nitrate solution,
on the other hand, consists of positively-charged lead ions and negatively-charged nitrate ions moving about in water. Zinc is more reactive than lead, which means it more readily gives up its electrons. So the zinc atoms lose their electrons to the lead ions. This turns the zinc atoms into positive ions, which move into solution, and the lead ions into lead atoms, which form beautiful metal crystals as they come out of solution. This is an oxidation reaction, too.
Do zinc atoms have an electrical charge?
Yes
No
Sometimes
Depends on the context
What are the two types of ions present in lead nitrate solution?
Positively-charged lead ions and negatively-charged nitrate ions
Neutral lead ions and positively-charged nitrate ions
Negatively-charged lead ions and positively-charged nitrate ions
Neutral lead ions and negatively-charged nitrate ions
Which metal is more reactive than lead and readily gives up its electrons?
Zinc
Iron
Copper
Aluminum
Can oxidation reactions occur without the involvement of oxygen?
Yes
No
Sometimes
Rarely
What happens to zinc atoms when they lose electrons to lead ions?
They become negative ions
They remain neutral
They turn into positive ions
They become neutral atoms
What do lead ions turn into in an oxidation reaction?
Lead molecules
Lead atoms
Lead crystals
Lead particles
What can be formed from zinc and lead nitrate solution?
Gold trees
Silver trees
Lead trees
Copper trees
In the formation of lead trees from zinc and lead nitrate solution, why do zinc atoms lose their electrons?
The zinc has been oxidized because it lost electrons. But one atom's loss is another another's gain. And gain of electrons is called "reduction." So with burning magnesium, oxygen is reduced as magnesium is oxidized. And when lead trees form, lead is reduced as zinc is oxidized. Oxidation and reduction are really just different aspects of the same thing. So we mix the words together and call the combination "redox reactions." Redox reactions are reactions that involve the transfer of electrons.
Are oxidation and reduction different aspects of the same thing?
Yes
No
Sometimes
Not sure
What is the main feature of redox reactions?
Transfer of protons
Transfer of electrons
Transfer of neutrons
Transfer of photons
What happens to oxygen when burning magnesium?
It is reduced
It is oxidized
It remains unchanged
It is evaporated
What happens to lead when zinc is oxidized?
It is reduced
It is oxidized
It remains unchanged
It evaporates
What is the term used to describe the combination of oxidation and reduction?
Hydrolysis
Decomposition
Redox reactions
Polymerization
What happens to zinc when it loses electrons?
It is reduced
It is unchanged
It is ionized
It is oxidized
What is reduction?
Gain of electrons
Loss of electrons
Gain of protons
Loss of protons
In redox reactions like burning magnesium and the formation of lead trees, what is reduction?
In the reaction between zinc and lead nitrate to form lead trees, what happens to the zinc atoms?
Zinc atoms lose electrons and are oxidized.
Why is the formation of lead trees considered a redox reaction?
The formation of lead trees involves reduction of lead ions to lead metal, which is a redox reaction.
The passage states that "oxidation and reduction are really just different aspects of the same thing." What does this imply about redox reactions?
Redox reactions involve a transfer of electrons, with one species being oxidized (losing electrons) and another being reduced (gaining electrons).
You can remember which reactants are oxidized and which are reduced
using the mnemonic OILRIG. "Oxidation Is Loss and
Reduction Is Gain." OILRIG.
OILRIG stands for what in the context of redox reactions?
In the reaction between magnesium and oxygen, which reactant is oxidized according to OILRIG?
Zinc loses electrons in the formation of lead trees. Based on OILRIG, what term describes what happens to zinc?
