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2 years ago

Why must a new flu vaccine be manufactured annually?

Chemistry

1 answer:

mafiozo [28]2 years ago

7 0

Answer:

D or A

But I do know...

It's because new strains of the virus are constantly appearing and evolving, so the vaccine must change along with them.

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Which type of intermolecular or interatomic force does methylated spirits fall under?

Triss [41]

Of all the substances used, water possesses the strongest intermolecular forces (hydrogen bonds). Although hydrogen bonds exist in glycerin and methylated spirits as well, they are a little weaker than in water.

Intermolecular forces in ch3oh include London dispersion forces, dipole dipole attraction, and hydrogen bonding. Methylated spirits, a common industrial solvent, are mostly made of ethyl alcohol. Because methanol denatures ethyl alcohol, commercial supply is exempt from the typical taxes and charges imposed on alcohol. A quantity of methyl alcohol or phenol is added to make it so that drinking it will make you go blind. Alcohols have the hydrogen bonding and van der Waals intermolecular forces of attraction.

Learn more about hydrogen bonding here-

brainly.com/question/10904296

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4 0

2 years ago

Which of the following is most likely to be covalent? MgO CO CaO BaO

Kisachek [45]

Answer:

CaO

Explanation:

CaO is the only compound that is a non-metal and a non-metal. The rest of the compounds are ionic, or metal and non-metal.

8 0

3 years ago

Brass is a substitutional alloy consisting of a solution of copper and zinc. A particular sample of red brass consisting of 79.0

Bas_tet [7]

Answer: The molality and molarity of zinc in the solution is 4.07 m and 28.11 M respectively.

Explanation:

Solute is the substance which is present in smaller proportion in a mixture and solvent is the substance which is present in larger proportion in a mixture.

We are given:

(m/m) % of Cu = 79 %

This means that 79 g of copper is present in 100 grams of alloy.

(m/m) % of Zn = 21 %

This means that 21 g of zinc is present in 100 grams of alloy.

As, zinc is present in smaller proportion. So, it is solute and copper is the solvent.

Calculating molality of zinc:

To calculate molality of the zinc, we use the equation:

$Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ in grams}}$

where,

$m_{solute}$ = Given mass of solute (Zinc ) = 21 g

$M_{solute}$ = Molar mass of solute (Zinc) = 65.3 g/mol

$W_{solvent}$ = Mass of solvent (copper) = 79 g

Putting values in above equation, we get:

$\text{Molality of Zinc}=\frac{21\times 1000}{65.3\times 79}\\\\\text{Molality of zinc}=4.07m$

Calculating molarity of zinc:

To calculate volume of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of solution = $8740kg/m^3=\frac{8740kg\frac{1000g}{1kg}}{1m^3\times \frac{10^6cm^3}{1m^3}}=\frac{8740g}{1000cm^3}=8.740g/cm^3$

(Conversion factors used are: 1 kg = 1000 g & $1m^3=10^6cm^3$ )

Mass of solution = 100 g

Putting values in above equation, we get:

$8.740g/cm^3=\frac{100.0g}{\text{Volume of zinc}}\\\\\text{Volume of zinc}=11.44cm^3$

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}$

We are given:

Molar mass of zinc = 65.3 g/mol

Volume of solution = $11.44cm^3=11.44mL$ (Conversion factor: $1cm^3=1mL$ )

Mass of zinc = 21.0 g

Putting values in above equation, we get:

$\text{Molarity of zinc}=\frac{21\times 1000}{65.3\times 11.44}=28.11M$

Hence, the molality and molarity of zinc in the solution is 4.07 m and 28.11 M respectively.

4 0

4 years ago

Which polyatomic ion is found in the compound represented by the formula NaHCO3?

olga nikolaevna [1]

Answer is (2) - hydrogen carbonate

Explanation:

NaHCO₃ is an ionic compound which is made from Na⁺ and HCO₃⁻ ions. The decomposition is

NaHCO₃ → Na⁺ + HCO₃⁻

Among the resulted ions, Na⁺ is a monatomic ion while HCO₃⁻ is a polyatomic ion.

Polyatomic ions mean ions which are made of two or more different atoms.

HCO₃⁻ is made from 3 atoms as H, C and O. The name of HCO₃⁻ ion is bicarbonate or hydrogen carbonate.

8 0

3 years ago

All systems have. A. Output and feedback. B. Process and function. C. input,process,and sensors.

zvonat [6]

I think the Answer is C

7 0

4 years ago

Read 2 more answers