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3 years ago

PLS HELP ASAP

Chemistry

1 answer:

Scorpion4ik [409]3 years ago

5 0

Answer:

The concentration of hydroxide ions in a 3.5 is

C. 10.5

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The molar enthalpy is 447 kJ and the reaction is endothermic

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If an atom has 26 electrons, what is the least number of energy levels it has?

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3 years ago

How many grams of sodium acetate ( molar mass = 83.06 g/mol ) must be added to 1.00 Liter of a 0.200 M acetic acid solution to m

Pie

Answer: The mass of sodium acetate that must be added is 30.23 grams

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of acetic acid solution = 0.200 M

Volume of solution = 1 L

Putting values in above equation, we get:

$0.200M=\frac{\text{Moles of acetic acid}}{1L}\\\\\text{Moles of acetic acid}=(0.200mol/L\times 1L)=0.200mol$

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

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

$pH=pK_a+\log(\frac{[CH_3COONa]}{[CH_3COOH]})$

We are given:

$pK_a$ = negative logarithm of acid dissociation constant of acetic acid = 4.74

$[CH_3COONa]=?mol$

$[CH_3COOH]=0.200mol$

pH = 5.00

Putting values in above equation, we get:

$5=4.74+\log(\frac{[CH_3COONa]}{0.200})$

$[CH_3COONa]=0.364mol$

To calculate the mass of sodium acetate for given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Molar mass of sodium acetate = 83.06 g/mol

Moles of sodium acetate = 0.364 moles

Putting values in above equation, we get:

$0.364mol=\frac{\text{Mass of sodium acetate}}{83.06g/mol}\\\\\text{Mass of sodium acetate}=(0.364mol\times 83.06g/mol)=30.23g$

Hence, the mass of sodium acetate that must be added is 30.23 grams

7 0

3 years ago

In the determination of the specific heat of a metal, why is it desirable to use the minimum volume of water that will allow imm

Softa [21]

Answer:

Because it will allow a bigger temperature change.

Explanation:

The specific heat of the metal can be calculated by the heat change between it and the water. The total amount of heat must be 0, thus, the heat of the metal (Qm) plus the heat of water (Qw):

Qm + Qw = 0

The heat is the mass multiplied by the specific heat (c) and by the temperature change:

mm*cm*ΔTm + mw*cw*ΔTw = 0

mm*cm*ΔTm = - mw*cw*ΔTw

So, as higher is the value of mw, as low is the value of ΔTw, and if ΔTw is very low, and so the calculations may not be precise.

7 0

3 years ago