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2 years ago

1.Calculate the frequency of a chemical shift at 1.25 ppm using a 400 MHz NMR spectrometer.A)1500 HzB)450 HzC)320 HzD)500 Hz

Chemistry

1 answer:

Advocard [28]2 years ago

6 0

Answer:

Explanation:

Chemical shift is given as

Frequency/frequency of instrument

Let c = chemical shift

F = frequency

I = frequency of instrument

Chemical shift = frequency/frequency Instrument

1.25ppm = Frequency /400

We cross multiply to find frequency

Frequency = 400 x 1.25

Frequency = 500Hz

Option d is the answer since it is 500hz

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Let us check each statement one by one

a) Sb has a lower ionization energy but a higher electronegativity than I. : As per values given : Definitely Sb has lower ionization energy however the electronegativity of Sb is lower than that of iodine

b) Sb has a higher ionization energy but a lower electronegativity than I. FAlse:

Sb has lower ionization energy than I

c) Sb has a lower ionization energy and a lower electronegativity than I. True

d) Sb has a higher ionization energy and a higher electronegativity than I. False

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3 years ago

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If 2.9g of water is heated from 23.9C to 98.9C, how much heat (in calories) was added to the water?

tensa zangetsu [6.8K]

Answer:

Explanation:

we know that

ΔH=m C ΔT

where ΔH is the change in enthalpy (j)

m is the mass of the given substance which is water in this case

ΔT IS the change in temperature and c is the specific heat constant

we know that given mass=2.9 g

ΔT=T2-T1 =98.9 °C-23.9°C=75°C

specific heat constant for water is 4.18 j/g°C

therefore ΔH=2.9 g*4.18 j/g°C*75°C

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2 years ago

What is in the solar system?

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Answer:

All of the above

Explanation:

All of this is in the solar system.

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2 years ago

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What does the atomic weight of an element represent

Marrrta [24]

The nuclei of atoms also contain neutrons, which help hold the nucleus together. ... The total weight of an atom is called the atomic weight. It is approximately equal to the number of protons and neutrons, with a little extra added by the electrons.

The mass of a given atom, measured on a scale in which the hydrogen atom has the weight of one. Because most of the mass in an atom is in the nucleus, and each proton and neutron has an atomic weight near one, the atomic weight is very nearly equal to the number of protons and neutrons in the nucleus.

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2 years ago

A 2.912 g sample of a compounds containing only C, H, and O was completely oxidized in a reaction that yielded 3.123 g of water

Taya2010 [7]

Answer:

Explanation:

18 gram of water contains 2 g of hydrogen

3.123 gram of water will contain 2 x 3.123 / 18 = .347 g of hydrogen .

44 gram of carbon dioxide contains 12 g of carbon

7.691 gram of carbon dioxide will contain 12 x 7.691 / 44 = 2.1 g of carbon .

So the sample will contain 2.912 - ( .347 + 2.1 ) g of oxygen .

= .465 g of oxygen .

moles of Carbon = 2.1 / 12 = .175

moles of hydrogen = .347 / 1 = .347

moles of oxygen = .465 / 16 = .029

Ratio of moles of carbon , oxygen and hydrogen ( C,O,H )

= 0.175 : 0.029 : 0.347

= .175/ .029 : 1 : .347 / .029

= 6 : 1 : 12

So empirical formula = C₆H₁₂O

Let the molecular formula be $(C_6H_{12}O)_n$

molecular weight = n ( 6 x 12 + 12x 1 + 16)

= 100 n

Given 100 n = 100.1

n = 1

Molecular formula = C₆H₁₂O.

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2 years ago