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3 years ago

A solution with a hydroxide ion concentration of 4.15 × 10-3 m is and has a hydrogen ion concentration of .

1 answer:

6 0

A solution with a hydroxide ion concentration of 4.15 10^-3 m is basic and has a hydrogen ion concentration of 2.41 x10 ^-12

hydrogen ion calculation
= (H+) (OH-) = 1 x10^-14
let the concentration of H+ be represented by y

=( 4x10^-3)(y) = 1 x10^-14

divide both side by 4 x10^-3

y= 2.41 x10^-12m

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How can you distinguish between a solution, colloid, and suspension?

RSB [31]

Answer:

solution is clear solution while colloidal is between the solution and suspension. And in suspension particles are suspended.

Explanation:

In solution light can be passed without any scattering of light from solute particles while suspension is cloudy and having larger particle size than colloids, if suspension stands for a while particles will settle down easily.

In colloids light will scattered and dispersed by reflecting with large particles.

3 0

3 years ago

A buffer solution is composed of 4.00 4.00 mol of acid and 3.25 3.25 mol of the conjugate base. If the p K a pKa of the acid is

Reika [66]

Answer: The pH of the buffer is 4.61

Explanation:

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a+\log(\frac{[\text{conjuagate base}]}{[\text{acid}]})$

We are given:

$pK_a$ = negative logarithm of acid dissociation constant of weak acid = 4.70

$[\text{conjuagate base}]}$ = moles of conjugate base = 3.25 moles

$[\text{acid}]$ = Moles of acid = 4.00 moles

pH = ?

Putting values in above equation, we get:

$pH=4.70+\log(\frac{3.25}{4.00})\\\\pH=4.61$

Hence, the pH of the buffer is 4.61

8 0

3 years ago

A 1.800-g sample of solid phenol (C6H5OH(s)) was burned in a bomb calorimeter whose total heat capacity is 11.66 kJ/?C. The temp

vichka [17]

Answer:

The balanced chemical equation:

$C_6H_5OH(s)+7O_2(g)\rightarrow 6CO_2(g)+3H_2O(g)$

Heat of combustion per gram of phenol is 32.454 kJ/g

Heat of combustion per gram of phenol is 3,050 kJ/mol

Explanation:

$C_6H_5OH(s)+7O_2(g)\rightarrow 6CO_2(g)+3H_2O(g)$

Heat capacity of calorimeter = C = 11.66 kJ/°C

Initial temperature of the calorimeter = $T_1= 21.36^oC$

Final temperature of the calorimeter = $T_2= 26.37^oC$

Heat absorbed by calorimeter = Q

$Q=C\times \Delta T$

Heat released during reaction = Q'

Q' = -Q ( law of conservation of energy)

Energy released on combustion of 1.800 grams of phenol = Q' = -(58.4166 kJ)

Heat of combustion per gram of phenol:

$\frac{Q'}{1.800 g}=\frac{-58.4166 kJ}{1.800 g}=32.454 kJ/g$

Molar mass of phenol = 94 g/mol

Heat of combustion per gram of phenol:

$\frac{Q'}{\frac{1.800 g}{94 g/mol}}=\frac{-58.4166 kJ\times 94 g/mol}{1.800 g}=3,050 kJ/mol$

3 0

3 years ago

A piece of unknown metal with mass 30 g is heated to 110.0 °C and dropped into 100.0 g of water at 20.0 °C. The final temperatur

Ymorist [56]

Answer: The specific heat of metal is 0.821 J/g°C

Explanation:

When metal is dipped in water, the amount of heat released by metal will be equal to the amount of heat absorbed by water.

$Heat_{\text{absorbed}}=Heat_{\text{released}}$

The equation used to calculate heat released or absorbed follows:

$Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})$

$m_1\times c_1\times (T_{final}-T_1)=-[m_2\times c_2\times (T_{final}-T_2)]$ ......(1)

where,

q = heat absorbed or released

$m_1$ = mass of metal = 30 g

$m_2$ = mass of water = 100 g

$T_{final}$ = final temperature = 25°C

$T_1$ = initial temperature of metal = 110°C

$T_2$ = initial temperature of water = 20.0°C

$c_1$ = specific heat of metal = ?

$c_2$ = specific heat of water = 4.186 J/g°C

Putting values in equation 1, we get:

$30\times c_1\times (25-110)=-[100\times 4.186\times (25-20)]$

$c_1=0.821J/g^oC$

Hence, the specific heat of metal is 0.821 J/g°C

8 0

3 years ago

Francine makes several measurements of the mass of a metal block. The data set is shown in the table below.

BARSIC [14]

Answer:

Mean

Explanation:

The mean of a series of measurements is calculated when all the measurements are added up and then divided by the number of measurements taken, as follows:

Sum of Measurements = 20.73 + 20.76 + 20.68 + 20.75 = 82.92

As there are 4 measurements, the mean is:

Mean = 82.92 / 4 = 20.73

3 0

3 years ago

A solution with a hydroxide ion concentration of 4.15 × 10-3 m is ________ and has a hydrogen ion concentration of ________.

A solution with a hydroxide ion concentration of 4.15 × 10-3 m is and has a hydrogen ion concentration of .