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3 years ago

How many grams nano3 add to 500g of h20 prepare solution .5 molal nano3?

1 answer:

8 0

Answer is: mass of sodium nitrate is 21,25 g.
m(H₂O) = 500 g · 1 kg/1000 g = 0,5 kg.
b(solution) = 0,500 m = 0,500 mol/kg.
m(NaNO₃) = ?
b(solution) = n(NaNO₃) ÷ m(H₂O).
n(NaNO₃) = 0,500 mol/kg · 0,5 kg.
n(NaNO₃) = 0,25 mol.
m(NaNO₃) = n(NaNO₃) · M(NaNO₃).
m(NaNO₃) = 0,25 mol · 85 g/mol.
m(NaNO₃) = 21,25 g.

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A chemist must prepare 200.0 mL of hydrochloric acid solution with a pH of 0.60 at 25 °C. He will do this in three steps: • Fill

Likurg_2 [28]

Answer:

In the second step, the chemist must measure 8.3 ml of concentrated acid

Explanation:

The concentration of the final solution can be obtained using the pH value:

pH = -log[H] = 0.60

[H] = 10^(-0.60) = 0.25 M

Then, the final concentration of HCl will be 0.25 M because HCl is a monoprotic acid, which means that HCl only has one hydrolyzable proton. Therefore: [HCl] = [H].

The number of moles of HCl in the final solution will be equal to the number of moles present in the volume taken from the stock solution:

n° of moles in the volume taken from stock solution = n° moles in the final solution.

The number of moles can be calculated as follows:

number of moles = concentration * volume

Then:

Ci * Vi = Cf * Vf

where

Ci = concentration of the stock solution

Vi = volume taken from the stock solution

Cf = concentration of the final solution

Vf = volume of the final solution

Replacing with the data, we can obtain Vi:

6.0 M * Vi = 0.25 M * 200.0 ml

5 0

3 years ago

Please help! How many grams is 4.5 x 10^27

Eva8 [605]

Answer: The answer is 4.5e+27 grams, I hope I helped!

Explanation: N/A (I threw away my paper ^^")

4 0

3 years ago

The active ingredient in aspirin is acetylsalicylic acid. A 2.79 g sample of acetylsalicylic acid required 30.15 mL of 0.5137 M

vivado [14]

Answer:

Molar mass = 180 g/mol

Ka = 3.31x10⁻⁴

Explanation:

Because the acetylsalicylic is a monoprotic acid, it only leaves 1 mol of H⁺ in the reaction, so, it's necessary 1 mol of NaOH for each 1 mol of acetylsalicylic acid. The number of moles of NaOH is the volume, in L, multiplied by the concentration:

n = 0.03015*0.5137 = 0.01549

Which is also the number of moles of the acid. The molar mass is the mass, in g, divided by the number of moles:

M = 2.79/0.01549

M = 180 g/mol

After reacting with the base, the conjugate base of the acid will be formed, and the equilibrium between the acid form (HA) and the conjugate base (A⁻) is a buffer. It formed 0.01549 moles of A⁻, which will react with the moles of H⁺ from HCl to form HA.

nH⁺ = nHCl = 0.01741*0.448 = 0.0078 mol

A⁻ + H⁺ ⇄ HA

0.01549 0.0078 0 Initial

-0.0078 -0.0078 +0.0078 Reacts

0.0078 0 0.0078 Equilibrium

For a buffer, the pH can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[A⁻]/[HA]

Because the volume is the same, we can use the number of moles instead of the concentration:

3.48 = pKa + log(0.0078/0.0078)

pKa = 3.48

pKa = -logKa

Ka = $10^{-pKa}$

Ka = $10^{-3.48}$

Ka = 3.31x10⁻⁴

5 0

2 years ago

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8 0

3 years ago

Type the correct answer in the box. Express your answer to two significant figures. An industrial vat contains 650 grams of soli

nikklg [1K]

88.98 %

The Balance Chemical Equation is as follow,

2 HCl + Pb(NO₃)₂ → 2 HNO₃ + PbCl₂

According to equation,

331.2 g (1 mole) Pb(NO₃)₂ produces = 278.1 g (1 mole) PbCl₂

So,

870 g of Pb(NO₃)₂ will produce = X g of PbCl₂

Solving for X,

X = (870 g × 278.1 g) ÷ 331.2 g

X = 730.5 g of PbCl₂

Therefore,

Theoretical Yield = 730.5 g

Also as given,

Actual Yield = 650 g

So using following formula for percentage yield,

%age Yield = (Actual Yield / Theoretical Yield) × 100

Putting values,

%age Yield = (650 g / 730.5 g) × 100

%age Yield = 88.98 %

Brianliest please and thank you.

6 0

3 years ago