Chemistry Answers

Determine the [H3O+(aq)] of a solution with a pH of 3.45.

Expressed in scientific notation, the answer is in the form a,b × 10–c.

red giant star becomes exhausted of nuclear fuel, the outer material is blown off into space leaving the inert Carbon. The remnant is known as WHITE DWARF.

the star is unable to generate heat when it runs out of hydrogen in its core leading to its contraction and expansion. It cools down and glows red. The helium fused into Carbon. The star is now a RED GIANT.

Draw the energy diagram of the reaction: Na(s) + ½Cl2 → NaCl.

Enthalpy (kJ/mol)

     Na(s) → Na(g)                       +108

     Na_(g) → Na⁺_(g) + e                   +496

     ½ Cl₂ →Cl_(g)                            +121

     Cl_(g) + e → Cl^-_(g)                      -349

What is the change in the internal energy of a system that absorbs 2,500 J of heat and that does 7,655 J of work on the surroundings in J? 

Calculate the value of ΔE in joules for a system that loses 50 J of heat and has 150 J of work performed on it by the surroundings.

Given the balanced equation:  CH₄ + 2 O₂ → CO₂ + 2H₂O 

If 3.6 moles of CH₄ react in the above reaction, how many moles of oxygen gas, O₂ reacted?

Calcium sulfate is known to form hydrates (ionic compounds with water that have well-defined ratios of the ionic formula unit to molecules of water, written CaSO4⋅nH2O). The water content of the hydrate can be determined by gravimetric analysis. How many molecules of water are present for every formula unit of CaSO4 in an unknown calcium sulfate hydrate if a complete drying of a sample to anhydrous caused its mass to decrease from 8.609g to 6.807g?

• Use 136.14g/mol for the formula mass of CaSO4
• Use 18.02g/mol for the formula mass of H2O

Why alkali metal does not react with carbon

What is the strength of the ionic interactions between an ion with 1 positive charges and an ion with 1 negative charges, when the distance between them is 16.4 nanometers and the solvent is benzene, with a dielectric constant of 4.6?