اختبر كيميتك

A mole of potassium dichromate contains

• 1 mol K

• 4 mol Cr

• 7 mol O

• 1 mol Cr

If the chemical formula of antimony oxide is Sb₂O₃ and that of sodium phosphate is Na₃PO₄, what is the molar mass of antimony phosphate ?

Sb = 121.76 u

P = 31 u

O= 16 u

......

• 216.8 g/mol

• 338.6 g/mol

• 460.4 g/mol

• 528.6 g/mol

What is the mass of aluminum in 306 g of aluminum oxide Al₂O₃?

Al = 27 u

O = 16 u

• 81 g

• 162 g

• 200 g

• 243 g

What is the mass of 4 atoms of

copper?.......... [ Cu=63.51 ]

• 254.2 g

• 2.37 x 10^-21g

• 5.7 x 10^-22 g

• 4.22 x 10^-22 g

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كمل يلا

What is the number of the molecules in a sample of ammonia NH₃ its mass equals 43.5 g ?............... molecules.

[N=14, H = 11 ]

a. b. c. d.

• 2.62 x 10²⁵

• 2.36 x 10²³

• 1.54 x 10²⁴

• 8.63 x 10^-16

On dissolving 1 mol of sodium chloride in water completely, the total number of ions equals ..........

• Avogadro's number

• 3 x Avogadro's number

• 2 x Avogadro's number

• 4x Avogadro's number.

The volume of hydrogen which is required to produce 11.2 L of water vapour (at STP) equals …………

• 68.2L

• 11.2L

• 44.8L

• 22.4L

The opposite graphical figure represents the thermal change which occurs during o a chemical reaction, What is the value of ΔH of this reaction ? ……….

• -30kJ

• -120 kJ

• +30 kJ

• +120 kJ

The opposite graphical figure shows the energy diagram of one of the chemical reactions :

What is the type of this reaction ? ………

What is the value of its ΔH ? ..........

• Exothermic /-20 kJ

• Endothermic /-20 kJ

• Exothermic /+20 kJ

• Endothermic /+20 kJ