[114]第4單元習作參考答案

(點我)[114]第4單元習作參考答案

[114]第3單元習作參考答案

(點我)[114]第3單元習作參考答案

[114]第4單元海報及廚房裡的科學偵探: 粉末材料的辨識之旅簡報

(點我)廚房裡的科學偵探:
粉末材料的辨識之旅 簡報

[114]Unit 4 Key Points Summary (English Version)

Activity 1 How to identify materials in the kitchen

1. Condiments in the kitchen: We can use our five senses to identify different condiments or powder materials.

 

 

2. Dissolution of condiments and powder materials:

(1) Put the sugar into the water, the sugar particles will slowly disappear, and mix evenly with the water to form sugar water, this process is the phenomenon of dissolution.

(2) Put the gauze containing granulated sugar into the water:

(1) There will be something yellow gossamer in the gauze

ran out, and the sugar particles slowly decreased.

    (2) Sugar dissolves in water and becomes visible to the naked eye

tiny particles that are missing; The water turns yellow

      , it tastes sweet.

 

 

(3) Observation of dissolution phenomenon:

①  Completely dissolved: sugar, table salt, baking soda, citric acid.

②  Does not dissolve easily: flour.

  (4) Examples of application of dissolution in life, such as adding salt to       soup to make the soup salty, adding granulated sugar to black tea, black       tea becoming sweet, washing powder dissolved in water, washing clothes,       etc. 

(5) It can also separate substances by using its dissolving properties.

 

 3. Under a fixed amount of water, the dissolution of granulated sugar is limited. Most water-soluble substances cannot dissolve more substances after reaching their soluble amount.

4. After raising the water temperature, the sugar water with precipitated particles at the bottom of the cup can continue to dissolve.

 

 

Activity 2 How to identify the acid and base of an aqueous solution

1. In addition to appearance characteristics, dissolution and other characteristics, condiments and powder materials also have different acid and alkali properties. It is impossible to accurately distinguish the acid and base of an aqueous solution using only the senses.

 

  ▲vinegar   ▲citric acid  ▲table salt  ▲granulated sugar ▲baking soda powder    

2. Using purple cabbage juice to encounter aqueous solutions with different acids and alkalinities will produce regular color changes, and the acidity and alkalinity of the aqueous solution can be judged.

  (1) Acidic aqueous solution: The color of purple cabbage juice becomes reddish after being added to the aqueous solution.

  (2) Neutral aqueous solution: The color of purple cabbage juice remains unchanged (purple) after being added to the aqueous solution.

  (3) Alkaline aqueous solution: The color of purple cabbage juice becomes blue-green after being added to the aqueous solution.

          ▲vinegar   ▲citric acid  ▲table salt  ▲granulated sugar ▲baking soda powder

Activity 3 How to identify materials using their properties

●Compare the "Condiment and Powder Material Characteristics Table" to identify and infer condiments and powder materials.