brodidit for students
Chemistry in daily life
Government jobs · Everyday science · 22 سوالات
نام: ____________________ تاریخ: ____________
The chemical formula of common salt is:
- A CaCl₂
- B Na₂CO₃
- C NaCl
- D KCl
The gas that makes up most of the Earth's atmosphere is:
- A Carbon dioxide
- B Oxygen
- C Nitrogen
- D Argon
Vinegar contains:
- A Lactic acid
- B Formic acid
- C Acetic acid
- D Citric acid
Baking soda is chemically:
- A Sodium carbonate
- B Sodium hydroxide
- C Calcium carbonate
- D Sodium bicarbonate
Diamond and graphite are both forms of:
- A Carbon
- B Sulfur
- C Phosphorus
- D Silicon
The pH of a neutral solution at 25 °C is:
- A 7
- B 0
- C 14
- D 1
Rusting of iron needs:
- A Nitrogen and water
- B Oxygen and water
- C Only water
- D Only oxygen
The most abundant gas in the Sun is:
- A Oxygen
- B Hydrogen
- C Carbon
- D Helium
The gas used by plants in photosynthesis is:
- A Hydrogen
- B Carbon dioxide
- C Nitrogen
- D Oxygen
Which of the following is a good conductor of electricity?
- A Dry wood
- B Copper
- C Rubber
- D Glass
The chemical symbol of gold is:
- A Au
- B Gd
- C Ag
- D Go
The gas used in fire extinguishers is mainly:
- A Oxygen
- B Nitrogen only
- C Carbon dioxide
- D Hydrogen
Water is a compound of:
- A Oxygen and carbon
- B Hydrogen and nitrogen
- C Hydrogen and oxygen
- D Hydrogen and carbon
The hardest natural substance is:
- A Graphite
- B Diamond
- C Steel
- D Quartz
Which gas is released when zinc reacts with dilute sulfuric acid?
- A Oxygen
- B Hydrogen
- C Carbon dioxide
- D Chlorine
The main ingredient of LPG is:
- A Methane
- B Ethanol
- C Acetylene
- D Propane and butane
The ripening of fruits is hastened by the gas:
- A Neon
- B Ethylene
- C Oxygen
- D Methane
Which metal is liquid at room temperature?
- A Lead
- B Mercury
- C Iron
- D Sodium
The pH of lemon juice is about:
- A 13
- B 7
- C 10
- D 2
Soap is made by the reaction of fats with:
- A An alkali such as sodium hydroxide
- B Salt water only
- C Alcohol
- D An acid
The compound used to treat acidity in the stomach is:
- A Acetic acid
- B Sodium chloride
- C Magnesium hydroxide
- D Hydrochloric acid
Chlorine is used in water mainly to:
- A Add minerals
- B Remove salt
- C Soften it
- D Kill germs
جوابی کلید
1. C, 2. C, 3. C, 4. D, 5. A, 6. A, 7. B, 8. B, 9. B, 10. B, 11. A, 12. C, 13. C, 14. B, 15. B, 16. D, 17. B, 18. B, 19. D, 20. A, 21. C, 22. D
Common salt is sodium chloride.
Nitrogen is about 78 percent of dry air. Oxygen is about 21 percent.
Household vinegar is a dilute solution of acetic acid.
Baking soda is NaHCO₃, sodium hydrogen carbonate.
They are allotropes of carbon with different structures.
A pH of 7 is neutral, below 7 is acidic and above 7 is basic.
Iron rusts when it is in contact with both oxygen and moisture.
The Sun is mainly hydrogen, with helium as the second most common.
Plants take in carbon dioxide and water, and release oxygen.
Metals such as copper have free electrons, so they conduct well.
Au comes from the Latin aurum.
Carbon dioxide displaces oxygen and cools the fire.
Its formula is H₂O.
Diamond is the hardest known natural material.
Zn + H₂SO₄ gives ZnSO₄ and hydrogen gas.
Liquefied petroleum gas is mostly propane and butane.
Ethylene is a plant hormone that promotes ripening.
Mercury melts at −39 °C.
Lemon juice is acidic because of citric acid.
This reaction is called saponification.
A base such as magnesium hydroxide neutralises excess stomach acid.
Chlorine disinfects drinking water.