Answer: Option (c) is the correct answer.
Explanation:
It is known that when we tend to dilute an impure product with too much of solvent then it will lead to dissolution of the solute. As a result, the chances of formation of crystal reduces.
And, when we increase the temperature then there will occur increase in the number of collisions between the solute and solvent molecules.
Hence, solubility of the solute also increases with increase in temperature, placing it on ice bath will further reduce the crystal formation, hence no crystal should be formed in the reaction.
Thus, we can conclude that the result of crystals boiling the impure product with too much solvent and then cooling on ice is that no crystals are produced.
It is false, hope this helps!
Answer:
B. Spring balance - a device used for measuring the weight or force of gravity acting on an object.
Explanation:
A Force is any interaction that changes the motion or position of an obkpjectbthatbit is interacting with. Whenever there is an interaction between two objects, there is a force exerted by each of the objects on one themselves.
Forces are generally divided into contact forces and non-contact over field forces.
In contact forces, the two objects physically in contact with each other. Examples of contact forces are push or pull forces, frictional forces, tensional forces, spring forces, etc.
Non-contact forces are forces in which the two objects interacting do no need to be physically in contact with one another. Examples include, gravitational forces, magnetic forces, electrical forces, etc.
Instruments used in measuring forces are known as force gauges.
From the instruments listed above:
A. A ruler is an instrument used in measuring length
B. Spring balance is a device used for measuring the weight or force of gravity acting on an object.
C. A thermometer is an instrument used in measuring temperature
D. A windbvane is an instrument used in measuring wind direction.
The statement that is true among
the following sentences is ‘Minerals can be elements or compounds’. Minerals cannot
be liquid in form and they are not organic. Minerals are inorganic and present
as solid in phase. When placed in water, they do not dissolve at all.
Balanced chemical reaction: Pb(NO₃)₂ (aq) + 2NaI(aq) → 2PbI₂(s) + 2NaNO₃(aq).
V(Pb(NO₃)₂) = 50 mL ÷ 1000 mL = 0.05 L, volume of solution.
c(Pb(NO₃)₂) = 0.1 mol/L; concentration of solution.
n(Pb(NO₃)₂) = c(Pb(NO₃)₂) · V(Pb(NO₃)₂).
n(Pb(NO₃)₂) = 0.1 mol/L · 0.05 L.
n(Pb(NO₃)₂) = 0.005 mol.
n(NaI) = c(NaI) · V(NaI).
n(NaI) = 0.1 mol/L · 0.05 L.
n(NaI) = 0.005 mol; amount of substance.
From chemical reaction: n(Pb(NO₃)₂) : n(NaI) = 1 : 2.
n(Pb(NO₃)₂) = 0.005 mol ÷ 2.
n(Pb(NO₃)₂) = 0.0025 mol; number of moles Pb(NO₃)₂ used.
n(NaI) = 0.005 mol; number of moles NaI used.
The limiting reagent is Pb(NO₃)₂.
n(PbI₂) = 0.005 mol.
m(PbI₂) = n(PbI₂) · M(PbI₂).
m(PbI₂) = 0.005 mol · 461 g/mol.
m(PbI₂) = 2.305 g; the theoretical yield of PbI₂.
