Path length is the overall distance traveled following the path of where the object travel. ... Displacement is the distance from the starting point of the object to its final point irregardless where it travels.

3 0

3 years ago

The Ka for formic acid (HCO2H) is 1.8 × 10-4. What is the pH of a 0.35 M aqueous solution of sodium formate (NaHCO2)?

anzhelika [568]

Answer:

9.36

Explanation:

Sodium formate is the conjugate base of formic acid.

Also,

$K_a\times K_b=K_w$

$K_b$ for sodium formate is $K_b=\frac {K_w}{K_a}$

Given that:

$K_a$ of formic acid = $1.8\times 10^{-4}$

And, $K_w=10^{-14}$

So,

$K_b=\frac {10^{-14}}{1.8\times 10^{-4}}$

$K_b=5.5556\times 10^{-11}$

Concentration = 0.35 M

HCOONa ⇒ Na⁺ + HCOO⁻

Consider the ICE take for the formate ion as:

HCOO⁻ + H₂O ⇄ HCOOH + OH⁻

At t=0 0.35 - -

At t =equilibrium (0.35-x) x x

The expression for dissociation constant of sodium formate is:

$K_{b}=\frac {[OH^-][HCOOH]}{[HCOO^-]}$

$5.5556\times 10^{-11}=\frac {x^2}{0.35-x}$

Solving for x, we get:

x = 0.44×10⁻⁵ M

pOH = -log[OH⁻] = -log(0.44×10⁻⁵) = 4.64

pH + pOH = 14

So,

5 0

3 years ago

How many atoms are in 3.690 moles of oxygen

sweet [91]

1 mole of any substance contains Avogadro's number.

So, 1 mole of O2= 6.023x10^23 molecules

3 mole of O2= 6.023x10^23x3 molecules

= 1.8069x10^24 molecules

Each molecule of Oxygen has 2 atoms.

therefore,

1.8069x10^24 molecules= 1.8069x10^24 x 2 atoms

= 3.6138x10^24 atoms.

4 0

3 years ago