A sample of N2 gas occupies 4.48 L volume under standard conditions (1 atm, 0⁰C).What is the mass of the sample? The atomic mass of N is 14

Which properties are characteristic for the nonmetals?

1. 1. high electrical conductivity
   2. large ionization energy
   3. high electronegativity
   4. low electron affinity

Concerning 2 x 10²⁴CO2 molecules, which statements are true? The molar mass is 44 g/mol.

1. 1. it is 12 moles
   2. it occupies 1.2 x 22.4 L volume under standard conditions
   3. it has a mass of 88 grams
   4. it consists of 3.6 x 10²⁴ atoms

Which of the following substances contain covalent bonds only?

1.  BaCl2(aq)
2.  CCl4(l)
3.  HCl(g)
4. NH4Br(aq)

Which of the following atoms are isotopes of each other?

X:  11 protons, 11 electrons, 12 neutrons

Y:  11 protons, 10 electrons, 12 neutrons

V:  11 protons, 11 electrons, 13 neutrons

W: 12 protons, 12 electrons, 12 neutrons

An aqueous solution is prepared by dissolving 6 g NaOH in 250 mL final volume. What is the molar concentration of the solution?

The molar mass of NaOH is 40 g/mol

The reaction is exothermic towards product formation. Which of the following changes of conditions will shift the equilibrium of the reaction to the right?

1. increase the pressure
2. increase the concentration of NH3.
3. increase the concentration of H2 gas
4. decreasing the temperature

When two elements, X (atomic number 13) and Y (atomic number 8), react the compound formed will be:

Which is the most basic solution?

Which set contains only polar molecules?

In any reaction where a calcium atom changes to calcium ion, the calcium atom

1. has lost an electron
2. has become an anion
3. has been oxidized
4. has achieved noble gas electron configuration

What is the oxidation number of Cr in K2Cr2O7

Which group has the greatest first ionization energy?

Water solutions of the following five compounds have the same molar Arrange them in the order of increasing pH.

How many grams of solid potassium chloride are needed to prepare 200 mL solution with 15 % m/m concentration?

The density of the solution is 1.2 g/mL.

Which are the oxidation-reduction reactions?

1-  2Na(s) + 2H2O(l)  -> 2NaOH(aq) + H2(g)

2-  2NaOH(aq) + H2SO4(aq)  -> Na2SO4(aq) + 2H2O(l)

3-  Ca²⁺(aq) + CO3 ^2─(aq)  -> CaCO3 (s)

4-  H2(g) + Cl2(g) -> 2HCl(g)

Choose the compound with an ester group

Which pairs are structural isomers?

The main product in the following reaction is:

Which statements are true for the following molecule in its open chain form?

1. It is an aldopentose
2. It has 4 chiral carbon atoms
3. It is a monosaccharide
4. It is a D-sugar.