Plz correct me if I'm wrong!!
1) Which of the following is a chemical change? (1 point)
Boiling of water
Melting a cube of ice
Dissolving 10 grams of salt in water
Splitting water into hydrogen and oxygen***
2) What is the mass of water that results from combining 2.0g of hydrogen with 16.0g of oxygen? (1 point)
14.0g
16.0g
18.0g***
20.0g
3) Why are plastic building blocks good for modeling molecules? (1 point)
They come in thousands of shapes and sizes.
They can be combined in many different ways.***
They are rigid and do not easily separate.
There are as many different colors as there are atoms.
4. What did Antoine Lavoisier’s experiments demonstrate? (1 point)
Atoms always split into pairs during a chemical change.
Mass is neither lost nor gained during a chemical change.***
Matter can be created during a chemical change.
Energy is neither lost nor gained during a chemical change.
looks good to me.
these are correct
1) Correct! Splitting water into hydrogen and oxygen is a chemical change. To determine this, we can consider the rearrangement of atoms and the formation of new substances. In this case, water (H2O) is being broken down into hydrogen (H2) and oxygen (O2). This involves a chemical reaction, which is characteristic of a chemical change.
2) Correct! The mass of water that results from combining 2.0g of hydrogen with 16.0g of oxygen is 18.0g. To find the mass of water, we need to consider the law of conservation of mass. This law states that matter is neither created nor destroyed in a chemical reaction. Since water (H2O) is formed by the combination of hydrogen (H2) and oxygen (O2), the total mass of the reactants should be equal to the total mass of the product. Therefore, the mass of water is equal to the sum of the masses of hydrogen and oxygen, which is 2.0g + 16.0g = 18.0g.
3) Correct! Plastic building blocks are good for modeling molecules because they can be combined in many different ways. To model molecules, we need a flexible material that allows us to rearrange the components. Plastic building blocks provide the necessary flexibility as they can be easily assembled and disassembled. They come in various shapes and sizes, allowing us to construct different molecular structures. By combining the blocks in different ways, we can represent the arrangement of atoms within molecules.
4) Correct! Antoine Lavoisier's experiments demonstrated that mass is neither lost nor gained during a chemical change. Lavoisier is known as the father of modern chemistry and is famous for his experiments on combustion. Through meticulous measurements, he showed that the total mass of reactants is always equal to the total mass of products in a chemical reaction. This observation supports the law of conservation of mass, which states that mass is conserved in chemical reactions. Therefore, Lavoisier's experiments provided evidence for this fundamental principle of chemistry.