Answer:
1. Sand Casting: Sand casting is a popular method used to create pewter objects. Here's how it's achieved:
- First, a pattern or model of the desired object is created using materials like wood, plastic, or metal.
- The pattern is then pressed into a special type of sand called green sand, leaving an impression.
- Next, the pattern is removed, leaving a cavity in the sand.
- Molten pewter is poured into the cavity and left to cool and solidify.
- Once cooled, the sand is carefully removed, revealing the pewter object.
2. Spin Casting: Spin casting, also known as centrifugal casting, is another way to mold pewter. Here's how it works:
- A rubber mold of the object is created, usually using a master pattern made of wax or another material.
- The rubber mold is placed in a casting machine that rotates at high speed.
- Molten pewter is poured into the mold while it spins.
- The centrifugal force evenly distributes the pewter, filling the mold's cavities.
- As the pewter cools, it solidifies and takes the shape of the mold.
- Once cooled, the mold is opened, and the pewter object is removed.
3. Die Casting: Die casting is a method used for producing high-quality pewter objects. Here's how it's done:
- A metal mold, called a die, is created to match the desired shape of the object.
- Molten pewter is injected into the die under high pressure.
- The pressure ensures that the pewter fills the mold completely and captures all the intricate details.
- After a short cooling period, the die is opened, and the pewter object is ejected.
Explanation:
These are just a few ways to form or mold pewter. Each method has its advantages and is suitable for different types of objects. It's important to choose the appropriate method based on the complexity of the design and the desired quality of the final product.
Answer:
False
Explanation:
Activation energy is the minimum amount of energy required for a reaction to proceed. Hence, for a reaction (endothermic and exothermic) to occur/proceed, the activation energy must be met. This is because, a reaction is only endothermic or exothermic when the reaction has started/occurred. If the activation energy is not produced, there will be no reaction in the first place.
NOTE: Exothermic reaction is a reaction that involves the release of energy (heat or light) into the surroundings. While endothermic reaction is a reaction that requires the input of energy or it absorbs energy from the environment.
2. Scientific Law
3. Chemistry
4. Experiment
B) Platinum
C) Promethium
D) Carbon
Answer : The valley between the two peaks is usually referred to intermediate formation of the reaction. The two mountain peaks when formed in a reaction the stable phase between them is exactly when an intermediate is formed and often observed on the curve.
The valley between two peaks
B.1,000
C.10,000
D.100,000