The rate constant for 1st order reaction is
K = (2.303 /t) log (A0 /A)
Where, k is rate constant
t is time in sec
A0 is initial concentration
(6.82 * 10-3) * 240 = log (0.02 /A)
1.63 = log (0.02 /A)
-1.69 – log A = 1.63
Log A = - 0.069
A = 0.82
Hence, 0.82 mol of A remain after 4 minutes.
I think its answer choice A because it would better to talk to their parents first and not take matters into your own hands.
Answer: 
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
Precipitation is a type of displacement reaction in which one the products is formed in the solid state.
Suspension mixture was their dinner if they were having spaghetti and meatballs. The right option is D.
Explanation:
Properties of suspension mixture are:
Bigger particles are seen in suspension, and they are visible by naked eye.
Suspension is a heterogenous mixture of either two or more substances.
Solute particles are not dissolved in solvent instead they are suspended as it is or in bulk.
Exhibits Tyndall effect.
Solid particles get sedimented easily.
A mixture of spaghetti and meatballs are suspension because two paricles are not dissoved, and they have separate phases on sphagetti and meat ball where liquid in meat ball drizzles to bottom and meatball remians on top.
It is physical change because ? has changed alone not with chemicals
