Molecular Composition | MCQs

Explanation

 Coal gas composition:

Typically contains around 50% hydrogen, 35% methane, and 10% carbon monoxide. 

Production method:

Coal is heated in the absence of air to produce these gases. 

Explanation

Explanation

The human body contains traces of many elements, and approximately 99% of its mass is comprised of just six essential elements:

1. oxygen
2. carbon
3. hydrogen
4. nitrogen
5. calcium
6. phosphorus

Another five elements—

1. sulfur
2. potassium
3. sodium
4. chlorine
5. magnesium

Make up about 0.85% of the remaining mass, bringing the total of essential elements to 11

Explanation

"6.022 × 10²³ atoms of carbon"

Correct — Each CO₂ molecule contains 1 carbon atom

So, 1 mole of CO₂ has 6.022 × 10²³ carbon atoms

Explanation

Formaldehyde contains:

• one carbon atom
• two hydrogen atoms
• one oxygen atom.

The formaldehyde formula is written CH2O or HCHO,

At room temperature, formaldehyde is a colorless, flammable gas that is a distinct, pungent smell.

It is also known as :

• methanal,
• methylene oxide,
• oxymethylene,
• methyl aldehyde
• oxomethane.