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2 years ago

Two characteristics of radiowaves

1 answer:

4 0

Radio waves have the same velocity as any other electromagnetic wave, which is the speed of light (300 000km/second). ... Radio waves have the longest wavelength in the whole electromagnetic spectrum. Gamma rays have the highest frequency and the shortest wavelength. The shorter the wavelength, the higher the frequency.

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B) How many kilograms of carbon dioxide are formed when 24.42 g of iron is produced?

charle [14.2K]

Answer:

0.0289 kg of CO2 will be formed

Explanation:

Step 1: Data given

Mass of iron produced = 24.42 grams

Atomic mass iron = 55.845 g/mol

Molar mass CO2 = 44.01 g/mol

Step 2: The balanced equation

Fe2O3 + 3CO → 2Fe + 3CO2

Step 3: Calculate moles iron

Moles iron = mass iron / molar mass iron

Moles iron = 24.42 grams / 55.845 g/mol

Moles iron = 0.437 moles

Step 4: Calculate moles CO2

For 1 mol Fe2O3 we need 3 moles CO to produce 2 moles Fe and 3 moles CO2

For 0.437 moles Fe we'll have 3/2 * 0.437 = 0.6555 moles CO2

Step 5: Calculate mass CO2

Mass CO2 = moles CO2 * molar mass CO2

Mass CO2 = 0.6555 moles * 44.01 g/mol

Mass CO2 = 28.85 grams = 0.0289 kg

0.0289 kg of CO2 will be formed

5 0

3 years ago

What is the concentration (in M) of a sample of the unknown dye with an absorbance of 0.25 at 542 nm?

Sladkaya [172]

Answer:

see explanation below

Explanation:

Question is incomplete, so in picture 1, you have a sample of this question with the missing data.

Now, in general terms, the absorbance of a substance can be calculated using the beer's law which is the following:

A = εlc

Where:

ε: molar absortivity

l: distance of the light in solution

c: concentration of solution

However, in this case, we have a plot line and a equation for this plot, so all we have to do is replace the given data into the equation and solve for x, which is the concentration.

the equation according to the plot is:

A = 15200c - 0.018

So solving for C for an absorbance of 0.25 is:

0.25 = 15200c - 0.018

0.25 + 0.018 = 15200c

0.268 = 15200c

c = 0.268/15200

c = 1.76x10⁻⁵ M

5 0

2 years ago

Estimate the enthalpy change for the combustion of one mole of acetylene, C2H2, to form carbon dioxide and water vapor. BE(C?H)

tia_tia [17]

Answer:

ΔH rxn = -1010 kJ/molC₂H₂

Explanation:

To obtain the enthalpy change for a reaction from bond energies what we do is to make an inventory of the bonds broken and formed for the balanced chemical reaction:

C₂H₂ + 5/2O₂ ⇒ 2CO₂ + H₂O

Bond Broken Bonds Formed

2 C-H + 1 C≡C + 5/2 O=O 4C=O + 2 H-O

Enthalpy bonds broken:

2 mol (456 kJ/mol)+ 1 mol (962 kJ/mol) + 5/2 mol (499 kJ/mol) = 3121.5 kJ

Enthalpy bond formed:

4 mol (802 kJ/mol) + 2 mol (462 kJ/mol) = 4132.0 kJ

ΔH rxn = H broken - H formed = 3121.5 kJ - 4132.0 kJ = - 1010 kJ (per mol C₂H₂ )

4 0

2 years ago

How to round the decimal 4.15 to the hundredths place?

gladu [14]

Answer:4.15 is already in the hundreths place so you are good!

if it was 4.155 then you would round it to 4.16 but its NOT that so the answer IS 4.15

Explanation:

8 0

2 years ago

Which of the following is an acceptable IUPAC name?(A) 3,6-dimethylheptane (B) 2-ethyl-3-methylheptane (C) 5-methyl-3-ethylhepta

bearhunter [10]

Answer:

D) 4-ethyl-4-methylheptane

Explanation:

The rules for naming of alkanes with substituents.

1. The carbon chain with the maximum number of carbon atoms must be selected as a parent chain.

2.Numbering should be done in such a way that each substituent gets the least number.

3. Substituents whose name comes before the another substituents's name in the English alphabet is written first.

4. Substituents are written first with their location in the chain and the name of the parent chain is done. Numbers are separated from numbers by comma and numbers are separated from letters by using hyphen.

Considering (a) 3,6-dimethylheptane

Violation of Rule - 2 mentioned above

The numbering of the parent chain is not done in a right way. Numbering must be done such that each substituent gets the least number. So, The correct name is 2,5-dimethylheptane

Considering (b) 2-ethyl-3-methylheptane

Violation of Rule - 1 mentioned above.

The carbon chain with the maximum number of carbon atoms must be selected as a parent chain. The parent chain selected is of 7 carbon atoms but the parent chain is of 8 carbon atoms. So, The correct name is 3,4-dimethyloctane

Considering (c) 5-methyl-3-ethylheptane

Violation of Rule - 3 mentioned above.

'e' comes before 'm' . So, ethyl- is written first than methyl- . So, The correct name is 3,6-dimethyloctane

Considering (d) 4-ethyl-4-methylheptane

This is a IUPAC name and following all the rules mentioned above.

3 0

2 years ago

Two characteristics of radiowaves​

Two characteristics of radiowaves