Is Matter Around Us Pure? Class IX

Magnalium is an alloy of

• Manganese and Aluminium

• Magnesium and Aluminium

• Manganese and Chromium

• Magnesium and Chromium

As air temperature increases, air can hold more water molecules, and its relative humidity decreases.

• True

• False

Amorphous solids:

• are more flexible at higher temperature

• include glasses

• do not have specific melting point

• all of these

How many moles are contained in 180 grams of water?

• 100

• 10

• 180

• 0.1

How many free surfaces exist in the case of solids?

• 1

• 2

• 3

• infinitely many

Which of these is a pair of isobars?

• ₆C ¹², ₈O¹⁶

• ₆C ¹³, ₆C¹⁴

• ₂₀Ca ⁴⁰, ₁₈Ar⁴⁰

• ₁₇Cl³⁵, ₁₇Cl³⁷

What is the mass of one mole of cane sugar? (Formula of cane sugar is C₁₂H₂₂O₁₁)

• 342 g

• 180 g

• 360 g

• 240 g

When the same amount of Zn is treated separately with excess of dil. H₂SO4 and excess of NaOH, what is the ratio of volumes of H₂ evolved?

• 1:1

• 1:2

• 2:1

• 9:4

If the formula of Chromic acid is H₂CrO4 , then what is the formula of divalent metal chromate?

• MCrO₄

• M₂CrO₄

• M₂(CrO4 )₃

• M₃CrO₄

How much lime is obtained by heating 400 g of limestone?

• 224 g

• 220 g

• 400 g

• 320 g