Answer:
A is denser than B as it's volume for the same mass is smaller.
Explanation:
Hello.
In this case, we first need to take into account that the density of each metal A and B is computed by dividing the mass over the volume of each metal which is actually computed by substracting the volume of water from the volume of the water and the solid:
Next, we compute the densities as shown below:
In such a way, A is denser is B as it's volume for the same mass is smaller.
Best regards.
The primary reason for this was that Mendeleev
didn't know that atomic numbers actually existed. Atomic numbers
were only discovered a period after Mendeleev's time. The use of X-rays made it
possible to find the atomic number, and those had not been discovered yet. <span>
<span>The periodic table was then arranged in 1913 by Henry Moseley
in an arrangement according to atomic number.</span></span>
Answer:
the true statement is... The pH of the weak acid will be higher than the pH of the strong acid
Explanation:
pH is a measured of the extent to which acids dissociate into ions when plced in aqueous solution.
Strong acid dissociate near-completely, and weak acids barely dissociate.
At equal concentrations, a strong acid will have a lower pH than a weak acid, since the strong one will donate more proton to the solution.
To determine which order of the reaction it is, first we need to calculate the rate of change of moles.
the data is as follows
time 0 40 80 120 160
moles 0.100 0.067 0.045 0.030 0.020
Q1)
for the first 40 s change of moles ;
= -d[A] / t
= - (0.067-0.100)/40s
= 8.25 x 10⁻⁴ mol/s
for the next 40 s
= -(0.045-0.067)/40
= 5.5 x 10⁻⁴ mol/s
the 40 s after that
= -(0.030-0.045)/40 s
= 3.75 x 10⁻⁴ mol/s
k - rate constant
and A is the only reactant that affects the rate of the reaction
rate = k [A]ᵇ
8.25 × 10⁻⁴ mol/s = k [0.100 mol]ᵇ ----1
5.5 x 10⁻⁴ mol/s = k [0.067 mol]ᵇ -----2
divide the 2nd equation by the 1st equation
1.5 = [1.49]ᵇ
b is almost equal to 1
Therefore this is a first order reaction
Q2)
to find out the rate constant(k), we have to first state the equation for a first order reaction.
rate = k[A]ᵇ
As A is the only reactant thats considered for the rate equation.
Since this is a first order reaction,
b = 1
therefore the reaction is
rate = k[A]
substituting the values,
8.25 x 10⁻⁴ mol/s = k [0.100 mol]
k = 8.25 x 10⁻⁴ mol/s /0.100mol
= 8.25 x 10⁻³ s⁻¹
