HR Police PC · General Science
Elements, compounds, periodic table, acids/bases and chemical reactions.
Study notes are still being prepared.
Don't wait — Shishya can teach you this topic right now, on demand.
Ask Shishya to teach this →Shishya is your personal tutor for this topic. Pick a starter or open a free chat.
Q1 · Chemistry · EASY
Which of the following is a chemical change?
Q2 · Chemistry · MEDIUM
The pH value of pure water at 25 degree Celsius is 7. Which of the following statements is correct about a solution with pH value of 5?
Q3 · Chemistry · MEDIUM
An element X has atomic number 17. In the modern periodic table, this element belongs to which group and period?
Q4 · Chemistry · HARD
A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. If the molecular mass of the compound is 180 u, what is the molecular formula of the compound? (Atomic masses: C = 12 u, H = 1 u, O = 16 u)
Q5 · Chemistry · EASY
Which gas is commonly known as 'laughing gas'?