Answer:
D
Explanation:
A The calcium chloride dissolves in solution
B The mass of the solution totals 20 g
C The temperature of the solution is 35 degrees
D The solution became lighter in color
The correct answer would be that <u>the solution became lighter in color.</u>
An increase in temperature can also be considered a sign of a chemical reaction but in this case, the dissolution of calcium chloride in water is in itself exothermic.
A change in the mass of the final solution could also be considered a sign of a chemical reaction but in this case, the total mass equals the addition of the individual masses of the reactant.
The dissolution of calcium chloride in water is not enough as evidence of a chemical reaction. Dissolution can be a physical change of which, the evaporation of the water would retrieve the solute.
<em>A change in color, however, is one of the evidence to establish that a chemical reaction has occurred.</em>
The correct option is D.
Answer:
the last one
Explanation:
one atom had a higher electronegativity than the atom it is sharing with.
Answer:
2.11 g hydrobromic acid (correct to 3SF)
Explanation:
Molecular formula of hydrobromic acid = C2H5BrO2
mass of C2H5BrO2 = 140.96g
Beginning with what we're given, 9.03*10^21 we then make a conversion by using Avegadro's number which is 6.02*10^23 per mole (Oct. 23 at 6:02 am is national mole day :) Then, we need to convert out of moles, 140.96g hydrombromic acid per mole.
It looks like this:
9.03*10^21 molecules • (1 mol C2H5BrO2 / 6.02*10^23 molecules) • (140g C2H5BrO2 / 1 mol) = 2.1144 g C2H5BrO2
Answer:
B. Smaller Particles
Explanation:
We know that the rate of reaction increases with increase in the surface area of reactants.
The reacting particles in the log of wood are embedded inside the wood making only very minimal amount of particles available for reaction. This ultimately slows down the rate of combustion.
However, in saw dust, there is a greater availability of surface area of reactants hence the sawdust burns faster than logs.
Mg(s)+2HCl(aq)→MgCl2(aq)+H2(g)
(since the molar mass of Mg is not given, assuming that it's mola mass is 24gmol¯1)
1st find the moles of Mg using the equation n=m/M where
n - moles
m - mass
M - molar mass
Therefore :
n = 0.39375mol
n = 0.39mol
Then using the equation n=V/Vm where;
n = mol
V = volume
Vm = molar volume
Find the volume.
n = V/Vm
(n =0.39mol , Vm = 22.4dm³mol¯¹)
V = 0.39mol×22.4dm³mol¯¹
V = 8.736dm³
