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3 years ago

Why is each year's vaccine different?

Chemistry

2 answers:

Degger [83]3 years ago

5 0

Because the birds that fly overseas carry different flu viruses every year.

Gemiola [76]3 years ago

5 0

Answer:

Flu vaccinations are needed each year to ensure you have continuous protection. Though you may have received a flu vaccine last year, your body's immune system from previous vaccinations gradually decreases over time. By the time flu season comes around, your body's immunity to it is virtuality non-existent.

Explanation:

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When the volume of a gas is changed from 11.5 cm3 to ?cm the temperature will change from 415 K to 200 K

Sonja [21]

Assuming that the gas acts like an ideal gas, we can calculate for the final volume using the ideal gas law:

PV = nRT

Where P = pressure, V = volume, n = number of moles, R = gas constant, and T = temperature

Assuming that P, n, and R are constant throughout the process, we can define another constant K:

V / T = K where K = nR / P

Equating the initial and final states:

Vi / Ti = Vf / Tf

Substituting the given values:

11.5 cm^3 / 415 K = Vf / 200 K

Vf = 5.54 cm^3

4 0

3 years ago

Which force prevents protons from repelling each other inside a nucleus?

telo118 [61]

Which force prevents protons from repelling each other inside a nucleus?

the gravitational force

the weak nuclear force

the electromagnetic force

<u>the strong nuclear force</u>

5 0

3 years ago

3.5g of a Certain compound X, known to be made of carbon, hydrogen, and perhaps oxygen, and to have a molecular molar mass of 15

shutvik [7]

Answer:

C₅H₁₀O₅

Explanation:

1. Calculate the mass of each element in 2.78 mg of X.

(a) Mass of C

$\text{Mass of C} = \text{5.13 g CO}_{2}\times \dfrac{\text{12.01 g C}}{\text{44.01 g }\text{CO}_{2}}= \text{1.400 g C}$

(b) Mass of H

$\text{Mass of H} = \text{2.10 g H$_{2}$O}\times \dfrac{\text{2.016 g H}}{\text{18.02 g H$_{2}$O}} = \text{0.2349 g H}$

(c) Mass of O

Mass of O = 3.5 - 1.400 - 0.2349 = 1.87 g

2. Calculate the moles of each element

$\text{Moles of C = 1400 mg C}\times\dfrac{\text{1 mmol C}}{\text{12.01 mg C }} = \text{116.6 mmol C}\\\\\text{Moles of H = 234.9 mg H} \times \dfrac{\text{1 mmol H}}{\text{1.008 mg H}} = \text{233.1 mmol H}\\\\\text{Moles of O = 1870 mg O} \times \dfrac{\text{1 mmol O}}{\text{16.00 mg O}} = \text{116 mmol O}$

3. Calculate the molar ratios

Divide all moles by the smallest number of moles.

$\text{C: } \dfrac{116.6}{116.6}= 1\\\\\text{H: } \dfrac{233.1}{116.6} = 1.999\\\\\text{O: } \dfrac{116}{116.6} = 1.00$

4. Round the ratios to the nearest integer

C:H:O = 1:2:1

5. Write the empirical formula

The empirical formula is CH₂O.

6. Calculate the molecular formula.

EF Mass = (12.01 + 2.016 + 16.00) u = 30.03 u

The molecular formula is an integral multiple of the empirical formula.

MF = (EF)ₙ

$n = \dfrac{\text{MF Mass}}{\text{EF Mass }} = \dfrac{\text{150 u}}{\text{30.03 u}} = 5.00 \approx 5$

MF = (CH₂O)₅ = C₅H₁₀O₅

The molecular formula of X is C₅H₁₀O₅.

8 0

4 years ago

What is the current temperature to the nearest degree for the thermometer shown below?

padilas [110]

There is no temperature at all shown below. Is that the same as Absolute Zero ?

3 0

3 years ago

Read 2 more answers

In a sample of oxygen gas at room temperature, the average kinetic energy of all the balls stays constant. Which postulate of ki

Levart [38]

Answer:

Collisions between gas particles are elastic; there is no net gain or loss of kinetic energy.

Explanation:

When a gas is paced in a container, the molecules of the gas have little or no intermolecular interaction between them. There is a lot of space between the molecules of the gas.

The gas molecules move at very high speed and collide with each other and with the walls of container.

The collision of these particles with each other is perfectly elastic hence the kinetic energy of the colliding gas particles do not change.

7 0

3 years ago