This is related to the amount
100 grams of calcium oxide reacts with the amount of grams of water to form calcium hydroxide. The heat of reaction is 27.8 kcal
The following is. the calculation method
< p>CaO+H2O=Ca(OH)256 18 74
100g 32.14g 132.14
Assuming that CaO reacts completely, 56/100＝18/x x＝ 24.32 grams The heat of reaction can be calculated using the difference in enthalpy of formation of CaO water and calcium hydroxide. The table shows that the enthalpy of formation of CaO is -635.1 KJ. /mol, H2O is -285.8KJ/mol and Ca(OH)2 is -986.1KJ/mol, at this time, Ca(OH)2 is (132.14/74) mol, H2O is 32.14/18mol, Cao is 100/56mol
The heat of reaction is therefore -986.1× (132.14/74) -(-635.1)×(100/56 )-(-285.8)×32.14/18＝-116KJ＝27.8 kcal.
What is the reaction phenomenon between calcium oxide and water?
Ca(OH)2(s) + H2O ---> Ca2+(aq) + 2OH-(aq)< /p>
The heat of hydratation of Ca2+ is not high, and the heat of dissolution is mainly due to the very high heat of OH- water
So all strong bases release a lot of heat when dissolved in water
Mainly because OH- changes from an isolated state in the crystal lattice to a hydrated ion, releasing a large amount of energy
The phenomenon of reaction between calcium oxide and water: the solution boils and the solution becomes cloudy.
Calcium oxide is what we call quicklime. The reaction between calcium oxide and water releases a large amount of heat, causing the solution to boil, forming a white precipitate of calcium hydroxide, making the solution cloudy.
The reaction is divided into two types, one is pouring water into quicklime powder, and the other is putting quicklime into the water.
The first reaction phenomenon is that the water boils and evaporates graduallyessively, turning into a murky gray state in the middle. This is when all the water has completely reacted.
The second phenomenon is that the lime gradually dissolves and generates heat. This is fully reflected in all the quicklime.
Detailed information:
Protective measures against calcium oxide
1. Protection of the respiratory system: It is recommended to wear a dust mask with a self-priming filter when you risk being exposed to its dust.
2. Eye Protection: Wear chemical safety glasses if necessary.
3. Protective clothing: Wear acid and alkali resistant coveralls.
4. Hand protection: Wear rubber gloves.
5. Others: Smoking, eating and drinking are prohibited in the workplace and hands must be washed before meals. After the travail, take a shower and change your clothes. Pay attention to personal hygiene.
Health hazards of calcium oxide
1 Route of invasion: inhalation, ingestion.
2. Health Hazards: This product is an alkaline oxide that reacts with water in the human body to form strong alkaline calcium hydroxide and release a large amount of heat, which has irritant and corrosive effects. It is very irritating to the respiratory tract. Inhalation of dust from this product may cause chemical pneumonia. It is strongly irritating to eyes and skin and can cause burns. Oral irritation and digestive tract burns. Long-term exposure to this product may cause keratinization, cracking of the skin of the palms, and deformity of the fingers (nails).
Baidu Encyclopedia – Calcium Oxide