(HELP FAST)Which of the following always changes when a substance undergoes a<br> chemical change?

H A and H B are both weak acids in water, and HA is a stronger acid than HB. Which of the following statements is correct? Selec

lubasha [3.4K]

Answer:

B is a stronger base than A^-, which is a stronger base than H2O, which is a stronger base than CI^-

Explanation:

The general equation for each acid is:

HA(aq) + H2O(ac) ⇄ H3O+(aq) + A-(aq)

HB(aq) + H2O(ac) ⇄ H3O+(aq) + B-(aq)

When these acids dissociate into its ions in water they lose a proton (H+), so they are proton donors (acids) and H2O is the proton acceptor (base). This reaction produces a conjugate acid and a conjugate base.

Conjugate base is what remains of the acid molecule after it loses a proton:

HA = acid A- Conjugate base

HB = acid B- Conjugate base

A conjugate acid is formed when the proton is transferred to the base

H2O = base H3O+ = Conjugate acid

The stronger acid will produce a weaker base. According to this, if HA is a stronger acid than HB, A- would be the weaker base (B- is the stronger base).

Compared with water, A- and B- are stronger bases because when they compete for a proton they have much greater affinity for H+ than water does and the equilibrium position will lie far to the left. (HA and HB are weak acids)

Finally Cl- is the weakest base because it comes after dissociation of HCl which is a strong acid

HCl(aq) + H2O → H3O+(aq) + Cl-(aq)

Note there is no double arrows, equilibrium lies far to the right. A strong acid yields a weak conjugate base it means one that has a low affinity for a proton.

4 0

3 years ago

Write the overall equation for the conversion of pyruvate to acetyl coa. express your answer as a chemical equation.

Schach [20]

the overall equation for the conversation of pyruvate to acetyl COA is as below

CH3COO-COO- + NAD+ + HS-COA = ch3-COO-S -COA +NADH +CO2

The oxidation of pyruvate led to a conversation of NAD+ to NADH and produces acetyl COA and CO2

5 0

3 years ago

If the p-side has a higher doping concentration, explain how to keep tuning to the same radio channel?

zzz [600]

Answer:

increase in temperature of the intrinsic semiconductor

Explanation:

If the p-side has a higher doping concentration, it implies that number of holes (positive ion) increased which is greater than number of electron (negative ion) in the n-side
in order to balance the intrinsic concentration, that is to balance the number of holes and electrons which depends on temperature.
an increase in the temperature of the intrinsic semiconductor (p-side), increases the number of electron but number of holes remains constant.

A balance in the intrinsic concentration helps in tuning to the same radio channel.

6 0

4 years ago

What explains the fact that no machine is 100 percent efficient?

kati45 [8]

Hello, to answer your question. It is because all machines require a fuel or source to power it making it imperfect for using some source that may not be renewable.

Signed by, Virtouso Sargedog

3 0

3 years ago

1.5mol C3H8 from C3H8+5O2-->3CO2+4H2O .how many grams of carbon dioxide are produced

koban [17]

Answer:

$\large \boxed{\text{200 g CO}_{{2}}}$

Explanation:

We will need a balanced equation with masses, moles, and molar masses, so let’s gather all the information in one place.

Mᵣ: 44.01

C₃H₈ + 5O₂ ⟶ 3CO₂ + 4H₂O

n/mol: 1.5

1. Calculate the moles of CO₂

The molar ratio is 3 mol CO₂:1 mol C₃H₈

$\rm \text{Moles of CO}_{2} = \text{1.5 mol C$_{3}$H}_{8} \times \dfrac{\text{3 mol CO}_{2}}{\text{1 mol C$_{3}$H}_{8}} =\text{4.5 mol CO}_{2}$

2. Calculate the mass of CO₂.

$\text{Mass of CO}_{2} = \text{4.5 mol CO}_{2} \times \dfrac{\text{44.01 g CO}_{2}}{\text{1 mol CO$_{2}$}} = \textbf{200 g CO}_{\mathbf{2}}\\\text{The reaction will form $\large \boxed{\textbf{200 g CO}_{\mathbf{2}}}$}$

3 0

3 years ago

(HELP FAST)Which of the following always changes when a substance undergoes a chemical change?