Acids and bases
How is the reaction between acid and base called ?
Neutralization
Why are halogens so reactive?
They need one electron to complete their outer shell.
Name at least 4 elements from group VA.
Nitrogen, phosphorous, arsenic, antimony, bismuth
4
What is the pH of acid rain ?
Give the example of at least one substance that could be used in antacid tablets.
CaCO3, NaHCO3, MgO
Which halogen is used for making pan coatings ?
Fluorine
What are the allotropic forms of phosphorous. Describe them.
Red and White.
White phosphorus is a waxy, toxic solid that spontaneously combusts in air and glows in the dark, while red phosphorus is a non-toxic, amorphous powder that is much more stable and doesn't spontaneously ignite.
What are the main allotropic forms of carbon ? Describe each.
Diamond and graphite are both allotropes of carbon, meaning they are different structural forms of the same element, but they have vastly different physical properties due to their distinct atomic structures. Diamond is characterized by a tetrahedral crystal structure, making it extremely hard and transparent, while graphite has a layered structure that is soft, opaque, and conductive.
Name at least 3 greenhouse gases
CO2, CH4, N2O, H2O
A piece of marble is reacting with nitric acid. Write general and ionic equations.
CaCO3 (s) + 2 HNO3 (aq) → H2O (l) + CO2 (g) + Ca(NO3)2 (aq)
Describe the displacement reaction between chlorine and potassium iodide solution. What is observed and why?
Chlorine displaces iodine (Cl₂ + 2KI → 2KCl + I₂), iodine forms a brown solution due to lower reactivity.
Describe the production of nitric acid. All stages.
4NH3 + 5O2 --> 4NO + 6H2O
2NO + O2 --> 2NO2
4NO2 + O2 + 2H2O --> 4HNO3
We use baking soda for baking pies. Why ?
Explain it with reaction equation.
2 NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g)
How is acid rain formed ? Explain with equations.
SO3 + H2O --> H2SO4
4NO2 + O2 + 2H2O --> 4 HNO3
The pH of rain decreased from 6 to 4. How many times did the concentration of hydrogen ions change ?
Increased 100 times.
5g of zinc is reacting with excess of hydrochloric acid. 1,5 L of gas was released.
86%
Copper is reacting with diluted nitric acid. Write a balanced equations and oxidation-reduction half-equations.
3Cu + 8HNO3 → 3Cu(NO3)2 + 4H2O + 2NO
Write the formulas:
a) 3-methylpentane
b) 2,2,3,5,5-pentamethylhexane
c) 4-ethyl-2,4-dimethylhexane
d) 4-ethyl-2,3,3,5-tetramethylheptane
e) 2,2-dimethylpropane
*
A coal-fired power plant burns 1.00 × 10⁶ kg of coal containing 2.5% sulfur by mass every day. When sulfur is burned, it forms sulfur dioxide (SO₂), which contributes to acid rain. Calculate the mass of sulfur dioxide emitted per day.
49900 kg
Calculate the volume of gas that is released if 5g of magnesium is reacting with 200g 8% HCl ?
4.7 L
How many grams of salt will be formed if 5g of iron reacts with 10g of chlorine? Reaction yield is 80%.
14.5g
227 litres of ammonia are dissolved in 1 liter of water. Find the percentage of ammonia in the solution.
14.5%
The compound is composed of 92.31% carbon and 7.69% hydrogen. The density of this compound relative to hydrogen is 13. Determine the formula of the compound.
C2H2
While measuring air pollution in Preila, it was determined that the concentration of sulfur dioxide (SO₂) is on average 1.6 × 10⁻⁶ g/m³ of air. Calculate what volume of air would be needed to form one drop of concentrated sulfuric acid (drop volume 0.0040 cm³, ρ = 1.84 g/cm³). Show your step-by-step solution.
3000 m3