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3 years ago

How many grams of potassium nitrate (KNO3) are required to prepare 0.250L of a 0.700 M

Chemistry

1 answer:

CaHeK987 [17]3 years ago

6 0

Answer:

17.78g

Explanation:

m/M = C×V

m/101.102= 0.7× 0.25

m= 101.102×0.7×0.25= 17.78g

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Calculate the wavelength (in nm) of the blue light emitted by a mercury lamp with a frequency of 6.32 × 1014 Hz.

tester [92]

Answer:

474 nm or 4.74 x 10^2 nm

Explanation:

c = λv

c (speed of light) = 2.998 x 10^8 m/s

λ = ?

v = 6.32 × 1014 Hz = 6.32 × 1014 1/s

2.998 x 10^8 m/s = (λ)(6.32 × 10^14 1/s)

λ = (2.998 x 10^8 m/s) / (6.32 × 10^14 1/s)

λ = 4.74 x 10^-7 m

λ = 4.74 x 10^-7 m x (1 x 10^9 nm/1 m) = 474 nm

7 0

2 years ago

Suppose that Biuret reagent turns purple when it is added to an unknown substance. What can you conclude about the substance?

Oksi-84 [34.3K]

Answer:

the unknown substance is a protein

Explanation:

The biuret test is one of the tests for proteins. It can be used to detect peptide linkages. The biuret test is carried out in an alkaline solution. A coordination complex is formed leading to the appearance of a violet color.

Summarily, the biuret method is a colorimetric technique used to test for proteins and peptides. It involves the formation of a purple (violet) complex of Copper salts in alkaline solution.

Hence when the biuret reagent is added to an unknown substance and it turns purple, the unknown substance is a protein

6 0

3 years ago

A microwave can have a frequency of 3.8 X 1010Hz. How much energy does this microwave give off in joules?

Marina86 [1]

Answer:

2.52 x $10^{-23}$ J

Explanation:

The energy given off by the microwave can be determined by the application of Planck's energy formula:

E = hf

where: E is the required energy, h is Planck's constant (6.626 x $10^{-34}$ $m^{2}$ Kg/s), and f is the frequency (3.8 x $10^{10}$ Hz).

So that;

E = 6.626 x $10^{-34}$ x 3.8 x $10^{10}$

= 2.51788 x $10^{-23}$

Therefore, the energy released by the wave is 2.52 x $10^{-23}$ J.

3 0

3 years ago

intrusive igneous rock forms when the cooling of magma takes place fast on the top of the Earth's surface. A. True B. False

-BARSIC- [3]

Answer:

Explanation:

True igneous rock forms cooling of magma fast on the top

5 0

2 years ago

Read 2 more answers

explain using diagrams how potassium forms the compound potassium flouride when it reacts with flourine

Katarina [22]

Answer:

The answer to your question is given below.

Explanation:

Potassium (K) has 19 electrons with electronic configuration of 2, 8, 8, 1.

Fluorine (F) has 9 electrons with electronic configuration of 2, 7.

Fluorine needs 1 electron to complete it's octet configuration.

Hence, potassium (K), will lose 1 electron to fluorine (F) to form potassium ion (K+) with electronic configuration of 2, 8, 8. The fluorine atom (F) will receive the 1 electron from potassium to form the fluoride ion (F-) with electronic configuration of 2, 8.

**** Please see attached photo for further details.

7 0

2 years ago