What is the force of gravity acting on an object? (3 points)

Calculate the pH for each of the following cases in the titration of 25.0 mL of 0.150 M sodium hydroxide with 0.150 M HBr(aq). (

Taya2010 [7]

Answer:

a) pH = 13.176

b) pH = 13

c) pH = 12.574

d) pH = 7.0

e) pH = 1.46

f) pH = 1.21

Explanation:

HBr + NaOH ↔ NaBr + H2O

∴ equivalent point:

⇒ mol acid = mol base

⇒ (Va)*(0.150mol/L) = (0.025L)*(0.150mol/L)

⇒ Va = 0.025 L

a) before addition acid:

NaOH → Na+ + OH-

⇒ C NaOH = 0.150 M

⇒ [ OH- ] = 0.150 M

⇒ pOH = - Log ( 0.150 )

⇒ pOH = 0.824

⇒ pH = 14 - pOH

⇒ pH = 13.176

b) after addition 5mL HBr:

⇒ C NaOH = (( 0.025)*(0.150) - (0.005)*(0.150)) / (0.025 + 0.005) = 0.1 M

⇒ C HBr = (0.005)*(0.150) / ( 0.03 ) = 0.025 M

⇒ [ OH- ] = 0.1 M

⇒ pOH = 1

⇒ pH = 13

c) after addition 15mL HBr:

⇒ C NaOH = ((0.025)*(0.150) - (0.015)*(0.150 ))/(0.04) = 0.0375 M

⇒ C HBr = ((0.015)*(0.150))/(0.04) = 0.0563 M

⇒ [ OH- ] = 0.0375 M

⇒ pOH = 1.426

⇒ pH = 12.574

d) after addition 25mL HBr:

equivalent point:

⇒ [ OH- ] = [ H3O+ ]

⇒ Kw = 1 E-14 = [ H3O+ ] * [ OH- ] = [ H3O+ ]²

⇒ [ H3O+ ] = 1 E-7

⇒ pH = 7.0

d) after addition 40mL HBr:

⇒ C HBr = ((0.04)*(0.150) - (0.025)*(0.150)) / (0.04 + 0.025) = 0.035 M

⇒ [ H3O+ ] = 0.035 M

⇒ pH = 1.46

d) after addition 60mL HBr:

⇒ C HBr = ((0.06)*(0.150) - (0.025)*(0.150)) / (0.06+0.025) = 0.062 M

⇒ [ H3O+ ] = 0.062 M

⇒ pH = 1.21

8 0

4 years ago

Read 2 more answers

A chemical reaction has two elements as reactants. Which type of reaction might occur?

Elden [556K]

That should be a synthesis reaction

3 0

3 years ago

Read 2 more answers

a teacher divides her class into groups and assigns each group a task of measuring the mass of the same object three times.the t

RoseWind [281]

Answer:

This question lacks options, the options are:

A. Group C: 32.1 g, 35.0 g, 25.0 g

B. Group B: 25.5 g, 25.0 g, 24.8 g

C. Group A: 28.5g, 28.4 g, 28.5 g

D. Group D: 20.0 g, 25.0 g, 30.09

The answer is C. GROUP A

Explanation:

Precision in measurements refers to the degree of closeness between the repeated or measured values irrespective of how close they are to the true or accepted value, which is 25g in this case.

The precision of a measurement can be determined by simply finding the range (highest - lowest) of the measurements. The lowest range represents the most precise. The measurements for each group are:

Group C: 32.1 g, 35.0 g, 25.0 g

Range = 35.0 - 25.0 = 10g

Group B: 25.5 g, 25.0 g, 24.8 g

Range = 25.5 - 24.8 = 0.7g

Group A: 28.5g, 28.4 g, 28.5 g

Range: 28.5 - 28.4 = 0.1g

Group D: 20.0 g, 25.0 g, 30.09

Range = 30.09 - 25.0= 5.09g

Based on the ranges of the measurements in each group, one would notice that Group A has the lowest range (0.1g), hence, GROUP A is the most precise.

6 0

3 years ago

At STP what is the volume of 16.34 grams of nitrogen gas?

nika2105 [10]

Answer:

Volume = 13.06 L

Explanation:

We are given: mass of nitrogren gas = 16.34 g

We know: molar mass of nitrogen gas = 28.014 g/mol

: ideal gas law constant = 0.082 L.atm/K.mol

At STP: temperature = 273.15 K

: pressure = 1 atm

We first determine the number of moles of nitrogen gas:

n = m/M

= 16.34/28.014

= 0.58 mol

Using the ideal gas law:

$\begin{gathered} PV\text{ = nRT} \\ \\ \therefore V\text{ = }\frac{nRT}{P}\text{ = }\frac{0.58\times0.082\times273.15}{1}\text{ = 13.06 L} \end{gathered}$

6 0

1 year ago

What is the mass of silver that can be prepared from 1.50 g of copper metal?

noname [10]

Molar mass:

Ag = 107.86 g/mol
Cu = 63.54 g/mol

Mole ratio:

Cu(s)+2 AgNO₃(aq)→Cu(NO₃)₂(aq)+2 Ag(s)

63.54 g Cu ------------- 2 x 107.86 g Ag
1.50 g Cu -------------- ??

Mass Ag = 1.50 x 2 x 107.86 / 63.54

Mass Ag = 32358 / 63.54

= 509.25 g of Ag

hope this helps!

5 0

4 years ago