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3 years ago

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A student weighs out a 2.23 g sample of KF, transfers it to a 300 ml volumetric flask, adds enough water to dissolve it and then

adds water to the 300 mL tick mark What is the molarity of potassium fluoride in the resulting solution?

1 answer:

densk [106]3 years ago

7 0

Answer: i d8nt kn09.

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What is the term for a ratio of equivalent measurements that can be used to change a value from one until into another

Olegator [25]

Answer:conversion factor

Explanation:

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3 years ago

What is the wavelength of a photon with an energy of 3.50 x 10^-19 J ?

Leokris [45]

Answer:

λ = 5.68×10⁻⁷ m

Explanation:

Given data:

Energy of photon = 3.50 ×10⁻¹⁹ J

Wavelength of photon = ?

Solution:

E = hc/λ

h = planck's constant = 6.63×10⁻³⁴ Js

c = 3×10⁸ m/s

Now we will put the values in formula.

3.50 ×10⁻¹⁹ J = 6.63×10⁻³⁴ Js × 3×10⁸ m/s/ λ

λ = 6.63×10⁻³⁴ Js × 3×10⁸ m/s / 3.50 ×10⁻¹⁹ J

λ = 19.89×10⁻²⁶ J.m / 3.50 ×10⁻¹⁹ J

λ = 5.68×10⁻⁷ m

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3 years ago

Calcium carbonate is a compound that is used to make chalk for drawing on rocks or pavement. One molecule has one atom of calciu

Black_prince [1.1K]

Answer:

the chemical formula is caca3

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3 years ago

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Relate what you have learned about the word quantum to the Bohr model.

ss7ja [257]

I forgot what quantum means to be honest, the Bohr model In atomic physics, the Bohr model or Rutherford–Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar System, but with attraction provided by electrostatic forces in place of gravity. After the cubical model (1902), the plum pudding model (1904), the Saturnian model (1904), and the Rutherford model (1911) came the Rutherford–Bohr model or just Bohr model for short (1913). The improvement over the 1911 Rutherford model mainly concerned the new quantum physical interpretation.

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3 years ago

A person’s blood alcohol (C2H5OH) level can be determined by titrating a sample of blood plasma

Elanso [62]

Answer:

0.17%

Explanation:

With the equation:

2Cr2O7 2- + C2H5OH + H2O --> 4Cr3+ + 2CO2 + 11H2O

We can assume that every mole of ethanol needs 2 moles of Dichromate to react.

So if in 1L we have 0.05961 moles of dichromate we can discover how many moles we have in 35.46mL

1000 mL - 0.05962 moles

35.46 mL - x

x = $\frac{0.05962 * 35.46}{1000}$

x = 2,11* 10^-3 moles

As we said earlier, 1 mole of ethanol needs 2 mole of dichromate, so in the solution we have 1,055*10^-3 moles of ethanol. We can discover the mass of ethanol present in the solution.

1 mole - 46g

1.055*10^-3 - y

y = 46 * 1.055*10^-3

y = 0.048 g

To discover the percent of alchol we can use a simple relation

28 g - 100%

0.048 - z

z = $\frac{0.048 * 100}{28}$

z = 0.17%

6 0

4 years ago