A sample of brass is melted and poured into a mold to make a musical instrument. Which of the following correctly explains why brass is classified as a homogeneous mixture?
The components of brass are uniformly distributed and cannot be distinguished visually
Brass is an alloy of copper and zinc. In a homogeneous mixture the constituents are blended so evenly that the composition is the same throughout and the separate components cannot be told apart by the eye; this is exactly the case in brass.
"Chemically bonded and cannot be separated" is wrong: in a mixture the metals are not joined by chemical bonds, and they can be separated by physical or chemical means; the components keep their own properties.
"Made of only one type of atom" is wrong because brass contains two different metals (copper and zinc), not a single kind of atom.
"A compound formed by the reaction of zinc and copper" is wrong because brass is a mixture in a fixed-looking but variable ratio, not a chemical compound with a fixed formula.
Hence, brass is a homogeneous mixture because its components are uniformly distributed and cannot be distinguished visually.
What happens when acid is dissolved in water?
The molecular mass of carbon dioxide is:
Which of the following mixtures is NOT homogeneous?
Who was the first scientist to use the term 'element'?
Match the compound to its respective mass ratio by elements from the table given below.
| Compound | Mass Ratio by Elements |
| 1. Water (H2O) | A. 1 : 8 |
| 2. Carbon dioxide (CO2) | B. 14 : 3 |
| 3. Ammonia (NH3) | C. 3 : 8 |
| 4. Sulphur dioxide (SO2) | D. 1 : 1 |
If hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), which ions from each reactant participate in forming water?
Which of the following most accurately represents a heterogeneous mixture?
Among the following, what has a molecular mass of 44 u?
When 16 g of oxygen is combined with 2 g of hydrogen, 18 g water is formed. This observation is in accordance with:
Methyl orange turns red in:
Which of the following pair is correct?
I. Isotopes – different mass numbers
II. Isobars – different atomic numbers
Which of the following is a zone of a flame?
I. Dark
II. Luminous
III. Non-Luminous
If formula of sodium salt of an anion X is \(Na_2X\) , then the formula of its aluminium salt would be
Which of the following set contains same number of molecules?
A. 1 gram O 2, 2 grams SO 2
B. 1 gram CO 2, 1 gram N 2O
C. 1 gram O 2, 1 gram O 3
The volume of CO 2liberated at STP when 10 gm of 90% pure limestone strongly heated is