Answer:
1. a)
2. a)
3. b)
4. d)
Explanation:
The disposal method is how we throw away the wastes. In a chemical lab, the correct disposal method guarantees the security of the environment and the humans and animals that may be in contact with the materials.
So:
1. Excess chemical: Because it can be toxic, it may be disposed of in the appropriate waste container, which will depend on the characteristics of the material;
2. Reaction mixture: As the excess chemical, it can be toxic, so it must be disposed of at an appropriate waste container;
3. Used filter paper: Generally, the solids in the filter paper is not toxic, so it can be thrown away in the trash can;
4. Cracked or chipped beaker: Because the beaker is made of glass, it can cut when broken, so it must go to a broken glass box, that will protect the people that will deal with it.
At the complete combustion of butane the carbon dioxide and water are formed.
2C₄H₁₀ + 13O₂ = 8CO₂ + 10H₂O
C₄H₁₀ ⇒ 4CO₂, 5H₂O ⇒ 13O ⇒ 6.5O₂
we use integer coefficients: 8CO₂, 10H₂O, 13O₂
Answer:
If a substance undergoes a physical change, then it will retain most of its original properties because no new substance is formed.
If a substance undergoes a chemical change, then it will not retain its original properties because a new substance is formed.
Explanation:
So in shorter words its options 2 and 3
Answer: they both have large amounts of iron (Fe)
They are kind of opposite processes. Chemical synthesis is execution of chemical reactions to make products. Like you take two substances, you put them together, they react and you have new a substance. For example.

here Sodium and Chlorine react to make a new substance which is Sodium Chloride.
Chemical decomposition is process of seperating a substance to different substances. There is a substance by a reaction this substance becomes two substances, Like : XY -> X+Y For example :