Which of the following is true about cells?

Whose work directly resulted in the development of an atomic model that has negative electrons stuck within a sea of positive ma

miskamm [114]

Answer: Thomson

Explanation: It verified J. J. Thomson's work on the atomic structure.

3 0

3 years ago

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In which of the following compounds does the carbonyl stretch in the IR spectrum occur at the lowest wavenumber?

klio [65]

Answer:

a. Cyclohexanone

Explanation:

The principle of IR technique is based on the vibration of the bonds by using the energy that is in this region of the electromagnetic spectrum. For each bond, there is a specific energy that generates a specific vibration. In this case, you want to study the vibration that is given in the carbonyl group C=O. Which is located around 1700 cm-1.

Now, we must remember that the lower the wavenumber we will have less energy. So, what we should look for in these molecules, is a carbonyl group in which less energy is needed to vibrate since we look for the molecule with a smaller wavenumber.

If we look at the structure of all the molecules we will find that in the last three we have heteroatoms (atoms different to carbon I hydrogen) on the right side of the carbonyl group. These atoms allow the production of resonance structures which makes the molecule more stable. If the molecule is more stable we will need more energy to make it vibrate and therefore greater wavenumbers.

The molecule that fulfills this condition is the cyclohexanone.

See figure 1

I hope it helps!

4 0

3 years ago

Hypochlorous acid decays in the presence of ultraviolet radiation. Assume that degradation occurs accord- ing to first-order kin

Dennis_Churaev [7]

Answer:

35.75 days

Explanation:

From the given information:

For first-order kinetics, the rate law can be expressed as:

$\mathsf{In \dfrac{C}{C_o} = -kt}$

Given that:

the rate degradation constant = 0.12 / day

current concentration C = 0.05 mg/L

initial concentration C₀ = 3.65 mg/L

$\mathsf{In( \dfrac{0.05}{3.65})= -(0.12) t}$

㏑(0.01369863014) = -(0.12) t

-4.29 = -(0.12)

t = -4.29/-0.12

t = 35.75 days

3 0

2 years ago

A solution has a volume of 2.0 L and contains 36.0 grams of glucose (C6H12O6). If the molar mass of glucose is 180 g/mol, what i

zysi [14]

36.0 g of glucose divided by 180 g/mol = 0.200 moles of glucose

find molarity
0.200 moles of glucose / 2 liters = 0.100 molar solution

(hope this helps)

6 0

3 years ago

What mass of iron is produced from adding 80.0 g of iron(II) oxide (71.85 g/mol) to 20.0 g of magnesium metal? FeO (l) + Mg (l)

nadya68 [22]

Answer:

46.0g of Iron are produced

Explanation:

Based on the chemical reaction:

FeO(l) + Mg(l) → Fe(l) + MgO(s)

1 mole of Iron (II) oxide reacts per mole of Mg to produce 1 mole of iron

To solve this question we need to convert each mass of reactant to moles using its respectives molar masses in order to find limitng reactant. Moles of limiting reactant = Moles of iron produced:

Moles FeO (Molar mass: 71.85g/mol):

80.0g * (1mol / 71.85g) = 1.11moles FeO

Moles Mg (Molar mass: 24.305g/mol)

20.0g * (1mol / 24.305g) = 0.823 moles Mg

As moles of Mg < Moles FeO, Mg is limiting reactant and the moles of Fe are 0.823 moles.

The mass of Iron produced is:

0.823 moles Fe * (55.845g/mol) =

46.0g of Iron are produced

6 0

2 years ago