Which factor does NOT increase the rate of a chemical reaction?
Increasing temperature
Adding a catalyst
Increasing the concentration of reactants
Increasing the volume of the container
In the reaction of Na with H2O, the gas evolved is:
O2
H2
Cl2
N2
For the reaction: 2NO 2 (g)⇌N 2 O 4 (g) Which change will shift the equilibrium to the right?
Increasing temperature
Decreasing pressur
Adding a catalyst
Increasing pressure
Ionic Bond
creating by oppositely charged ions that attract.
creating by 2 non-metall that attract.
Reversible Reaction
A reaction can happen when no fire
A reaction can happen when no fixed tempeture
A reaction where the products can react to re-form the original reactants
A reaction can happen when increase pressure
Oxidation
loss of electrons
electrons change
gain of electrons
electrons transfer
Isotope
Atoms has the same electron but different numbers of neutrons
Atoms has the same proton and numbers of neutrons
Atoms has the same proton but different numbers of neutrons
A reaction that releases heat energy to the surroundings.
Dynamic Equilibrium
the system is opened
all the matter have same concentrations
Increasing the enthalpy change
In a reversible reaction, forward and backward have same rate
Covalent Bond
formed by the sharing of electron pairs between two atoms.
formed by the electron transfer
A reaction that absorb heat energy from the surroundings.
A reaction that releases heat energy to the surroundings.
Reduction
loss electrons
Providing an alternative reaction pathway with lower activation energy
gain of electrons
Shifting the equilibrium position towards products
Haber Process
nitrogen and hydrogen produce ammonia
produce SO2
produce SO3
produce NO2
Enthalpy Change (ΔH)
The amount of heat energy
The amount of chemical energy change in a reaction
Increasing the enthalpy change
The amount of heat energy change in a reaction
Exothermic Reaction
A reaction that releases heat energy to the system
A reaction that absorb heat energy to the system
A reaction that absorb heat energy from the surroundings.
A reaction that releases heat energy to the surroundings.
In sodium chloride (NaCl), the sodium ion has a ________ charge.
0
-1
2
+1
In the reaction 2Mg + O₂ → 2MgO, magnesium is ________.
oxidised
reduced
redox
Shifting the equilibrium position towards products
The chemical symbol for nitrogen is ________.
K
O
N
V
Zn is ________ (state of matter) at room temperature.
liquid
solid
gas
mixture
The process in which a solid changes directly into a gas is called ________.
melt
sublimation
condensation
freeezing
The formula for sulfuric acid is ________.
H2SO3
HCl
H2SO4
HNO3
生锈Rusting of iron requires the presence of both ________ and water.
O2
N2
H2
CO2
The number of electrons in the outer shell of a Group 1 element is ________.
0
8
1
2
In the reaction Zn + CuSO₄ → ZnSO₄ + Cu, the element that is oxidized is ________.
Zn
CuSO₄
ZnSO₄
Cu
In the Haber Process, the catalyst used is ________.
Fe
V2O5
H2
O2
Sodium reacts with water,list your observations:
bubbles
water turn cold
solid change bigger
no sounds
Sodium is stored in( ) to prevent it reacting with air
vessel
bottle
Water
oil
Which of the following is a balanced equation?
H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
H₂ + 2O₂ → H₂O
2H₂ + 2O₂ → 2H₂O
What is the empirical formula of C₆H₁₂O₆?
CH₂O
C₆H₁₂O₆
CHO
C₃H₆O₃
Balance: __Al + __O₂ → __Al₂O₃
2, 3, 2
4, 3, 2
1, 1, 1
3, 2, 1
Cl₂ + 2KI → 2KCl + I₂correctly describes the changes in oxidation number?
Chlorine is reduced (0 to -1), and iodine is oxidized (-1 to 0).
Chlorine is oxidized (0 to -1), and iodine is reduced (-1 to 0).
Chlorine is reduced (0 to +1), and iodine is oxidized (-1 to 0).
Chlorine is oxidized (0 to +1), and iodine is reduced (-1 to 0).
The charge of a proton is ________.
0
not stable
-1
+1
Which substance has a giant structure?
chlorine
Diamond
Water
Oxygen gas
Concentration Calculations
dm³
mol/dm³
dm³/g
g/mol
Why are metals good conductors of electricity?
They have free electrons
They have free protons
They are shiny
They are heavy
Which of these is a major greenhouse gas?
Oxygen
Hydrogen
Carbon dioxide
Nitrogen
Why is nitrogen gas used in food packaging?
It is flammable
It is reactive
It is an inert gas
It changes food color
What is the mass of 1 mole of C atom (Aᵣ = 12)?
6 g
12 g
24 g
1 g
Which gas do humans breathe out as a waste product?
Carbon dioxide
Oxygen
Nitrogen
Hydrogen
What causes cut apples to turn brown?
Reduction
Oxidation
Decomposition
Fermentation
A catalyst increases the rate of a reaction by:
Increasing the average kinetic energy
Providing an alternative reaction pathway with lower activation energy
Increasing the enthalpy change
Shifting the equilibrium position towards products
What would you observe if you added a few drops of 酚酞 to end of the reaction?
blue
white
pink
green
What is the formula of magnesium oxide?
MgO₂
Mg₂O
MgO
Mg₂O₂
An anion is:
A positively charged ion
A negatively charged ion
A neutral atom
A type of catalyst
displacement reaction:
Two elements combine to form a compound
A more reactive element replaces a less reactive one in a compound
A compound breaks down into simpler substances
Heat is always released
Thermal decomposition is:
The splitting of a compound using electricity
The breakdown of a compound by heat into simpler substances
A reaction with water
A type of polymerization
what gas collected from the reactionNa+H2O
O2
H2
CO
CO2
A hydrated salt contains:
Chemically bonded water molecules
Free water mixed with salt
Only anhydrous crystals
Oil molecules
Effervescence during a reaction refers to:
A color change
The formation of a precipitate
Rapid bubbling or fizzing due to gas release
An increase in temperature
Laboratory Safety: Eye Protection
To look more professional
To protect eyes from chemical splashes or flying particles
To avoid smelling chemicals
To keep dust out of eyes
Gas Collection Method
Downward
Upward
beaker
A gas syringe
Anhydrous means:
Containing water
Without water
Containing air
Without color
A common test for water uses anhydrous copper(II) sulfate. What color change indicates the presence of water?
Blue to white
White to blue
Pink to blue
Blue to pink
In the periodic table, elements in the same ________ have similar chemical properties.
period
group
block
state