Can anyone here help me with chemistry

A solution prepared by dissolving 0.100 mole of propionic acid in enough water to make 1.00 L of solution is observed to have a

torisob [31]

Answer:

C) $k_a=1.3\times 10^{-5}$

Explanation:

pH is defined as the negative logarithm of the concentration of hydrogen ions.

Thus,

pH = - log [H⁺]

The expression of the pH of the calculation of weak acid is:-

$pH=-log(\sqrt{k_a\times C})$

Where, C is the concentration = 0.5 M

Given, pH = 2.94

Moles = 0.100 moles

Volume = 1.00 L

So, $Molarity=\frac{Moles}{Volume}=\frac{0.100}{1.00}\ M=0.100\ M$

C = 0.100 M

$2.94=-log(\sqrt{k_a\times 0.100})$

$\log _{10}\left(\sqrt{k_a0.1}\right)=-2.94$

$\sqrt{0.1}\sqrt{k_a}=\frac{1}{10^{2.94}}$

$k_a=1.3\times 10^{-5}$

4 0

2 years ago

How many significant digits are in the measurements 14,433

Sunny_sXe [5.5K]

I believe there is 5.

3 0

3 years ago

How many liters are in 2.94 mol HCl?

nadezda [96]

Answer:

6 m

Explanation:

5 0

3 years ago

Elements with atomic numbers of 104 and greater are known as super-heavy elements. None of these elements have been found in nat

Lemur [1.5K]

Here we have to justify the work of scientists to generate more unknown elements after atomic number 104 which are so unstable and cannot be obtained in nature.

It is fact that the stability of the super heavy element is hard to obtain, as when there are so much proton and neutron at the nucleus of such element makes it so unstable.

So the try to make more unknown element to enlarge the periodic table is not justified as per the stability and utility of such elements are concerned. But in fact it helps to get the new elements which may exist and may have some radioactivity which can be used.

But apparently the making of new material in laboratory to expand the periodic table is not justified.

8 0

3 years ago

Read 2 more answers

A mass spectrometer is being used to monitor air pollutants. It is difficult, however, to separate molecules with nearly equal m

tatyana61 [14]

Answer:

4.2 m

Explanation:

The energy (E) of the selector region of the spectrometer is:

E = v*B (equation 1)

Where v is the velocity, and B the magnetic field.

The force with which particle forms a curved path can be calculated by:

$\frac{mv^2}{r} = qB'$

Where r is the radius of the particle, m is the mass, and q the electric charge. So:

$r = \frac{mv}{qB'}$

For equation 1: v = E/B, so:

$r = \frac{mE}{qBB'}$

The two species will be separated by Δr = 0.42 mm

Δr = Δm*E/(q*B*B')

E/(q*B*B') = r/m

Δr = Δm*r/m

r = m*Δr/Δm

r is the large of curvature, m is the avarege mass = (28.0106 + 28.0134)/2 = 28.012:

r = (28.012*0.42)/(28.0134 - 28.0106)

r = 11.76504/(0.0028)

r = 4201.8 mm

r = 4.2 m

3 0

2 years ago