Which of the following molecules contains atoms of only one element?
N2
A molecule of an element contains atoms of the same kind only, whereas a molecule of a compound contains atoms of two or more different elements combined in a fixed ratio.
N2 is made of two nitrogen atoms joined together, so it is a diatomic molecule of the element nitrogen and contains atoms of only one element.
CO2 contains carbon and oxygen atoms, HCl contains hydrogen and chlorine atoms, and NH3 contains nitrogen and hydrogen atoms, so all three are molecules of compounds.
Hence, N2.
Which of the following is an example of a suspension?
A student is given four samples: muddy water, air, milk, and salt dissolved in water. The task is to select the one that best represents a heterogeneous mixture. Which sample should the student choose?
If the atomic masses are: potassium 39 u, nitrogen 14 u, and oxygen 16 u, what is the formula unit mass of potassium nitrate (KNO3)?
What happens when more solute is added to a fixed amount of solvent in a solution?
A chemist wants to separate a mixture of sand and muddy water. She uses a filter paper and a funnel to accomplish this. Based on the properties of suspensions, which statement is correct why this method is effective?
Which of the following is the best example of a heterogeneous mixture?
Which method is commonly used to separate a mixture of two miscible liquids with different boiling points?
A sample of ammonia (NH3) contains 12 molecules. How many nitrogen atoms are present in the sample?
What is the correct chemical formula for calcium phosphate, given that calcium has a valency of 2 and phosphate has a valency of 3?
Which of the following is most likely to dissolve completely in water at room temperature?
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