Which of the following elements would displace copper from a solution of copper ions?
silver
gold
lead
mercury
Correct answer is C
The reactivity series allows us to predict how metals react. A more reactive metal displaces a less reactive metal from a compound. Lead is more reactive metal than copper hence, copper is displaced from copper solution by lead.
1.0 mol dm\(^{-3}\)
1.5 mol dm\(^{-3}\)
2.0 mol dm\(^{-3}\)
5.0 mol dm\(^{-3}\)
Correct answer is A
V= 50cm\(^{3}\)
Mass= 5.05g
Relative molecular mass of KNO\(_{3}\) = (39+14+(3*16)) = 101
Convert 50cm\(^{3}\) to dm\(^{3}\) which is
1000cm³ = 1dm\(^{3}\)
50cm³ = 50*1/1000
= 0.05dm\(^{3}\)
Moles = mass/ molar mass
= 5.05/101 =0.05mole
Solubility= mole/volume
Solubility=0.05mol/0.05dm\(^{3}\)
Solubility=1.0mol/dm_\(^{3}\)
0.32
1.52
3.13
31.25
Correct answer is C
P = 10atm, T= 320K, V= 8.2dm\(^{3}\)
PV =nRT
n = P * V/R * T
10 * 8.2/0.082 * 320
= 82/26.24
n = 3.13
Which of the following statements about liquids is/are true?
I. Liquids maintain their volume at constant temperature.
II. Liquids have fixed shape
III. Liquids do not diffuse
IV. Change in pressure affects volume of liquids
I only
IV only
I and IV only
II and III only
Correct answer is A
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure
When air in a syringe is compressed such that there is no change in temperature, the
air liquefies
pressure increases
intermolecular space increases
density decreases
Correct answer is B
Since the temperature of air remain constant.So, it is a isothermal process.
PV=K
This eq. shows that on increasing pressure, the volume gets reduced and vice-versa.
Since the syringe is slowly compressed, volume is decreasing.
Therefore, the pressure inside the syringe will increases because the molecules now hit the syringe walls more frequently.
Consider the following reaction equation
N\(_{2}\)(g) + 3H\(_{2(g)}\) ⇌ 2NH3(g) ∆H = -92kJ
Increasing the temperature of the reaction would
shift the equilibrium to the right
increase the yield of ammonia
decrease the amount of hydrogen
decrease the yield of ammonia
Correct answer is D
In this case, an increase in in temperature will cause the equilibrium position to shift to the left thereby decreasing the yield of ammonia.
Which of the following statements about an equilibrium system is correct?
Forward and backward reactions occur at the same rate
The concentrations of reactants must equal that of the products
The concentrations of, reactants and products can be changed by adding a catalyst,
The concentrations of reactants and products are not affected by a change in temperature
Correct answer is A
Equilibrium is a state of a system where there is no observable change in the properties of the system with respect to time
Which of the following gases is alkaline?
NO\(_{2}\)
CO\(_{2}\)
NH\(_{3}\)
N\(_{2}\)O
Correct answer is C
Alkaline gases are any gaseous compounds that form an alkali (or basic) solution with a pH greater than 7 when dissolved in water. Ammonia is the most common alkaline gas
Graphite is used as a dry lubricant due to the presence of
mobile electrons
free electrons
octahedral structures
layered structures
Correct answer is D
Graphite is an excellent dry lubricant. This is because its layered structure allows one layer to slide over another easily. It is non-volatile and not sticky.
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