Can someone help me with these please?
1) Use water as an example to contrast the properties of a compound with the elements from which it is composed.
2) If you tried to breath carbon dioxide, you would suffocate. Why, then, is carbon dioxide essential to all life on Earth?
We shall be happy to critique your thoughts. Hint: Look up the properties of oxygen and hydrogen and contrast those properties with those of water.
2. Hint: Plants need CO2 for photosynthesis.
Oh, thanks. I already have the first one. And I think your hint for the second should be sufficient enough.
1) To contrast the properties of a compound with the elements from which it is composed, let's consider water as an example. Water (H2O) is a compound made up of two elements, hydrogen (H) and oxygen (O).
If we compare the properties of water to the properties of its individual elements, we can see several contrasts.
i) State: Hydrogen is a colorless, odorless gas, while oxygen is also a colorless, odorless gas. However, water exists as a liquid at room temperature and normal atmospheric pressure.
ii) Melting and boiling points: Hydrogen has a very low boiling point (-252.9 degrees Celsius) and melting point (-259.14 degrees Celsius), whereas oxygen has a slightly higher boiling point (-183 degrees Celsius) and melting point (-218.4 degrees Celsius). In contrast, water has significantly higher boiling point (100 degrees Celsius) and melting point (0 degrees Celsius).
iii) Density: Hydrogen and oxygen are both less dense than water. For example, hydrogen gas is about 14 times less dense than air, while oxygen gas is about 1.1 times denser than air. Water, however, is approximately 800 times denser than air.
iv) Chemical reactivity: Hydrogen is highly flammable and reacts explosively with oxygen. Oxygen supports combustion but does not burn itself. In contrast, water does not readily ignite or support combustion.
These examples highlight the contrasting properties between water (a compound) and its constituent elements (hydrogen and oxygen).
2) Carbon dioxide (CO2) is essential to all life on Earth, despite being harmful to human respiration, because it plays a crucial role in the process of photosynthesis carried out by plants.
During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose (a type of sugar) and oxygen. Oxygen is released into the atmosphere as a byproduct, which is necessary for most organisms, including humans, to survive.
Additionally, carbon dioxide regulates the Earth's temperature through the greenhouse effect. It absorbs and redirects heat energy radiated from the Earth's surface, keeping the planet warm enough for life to exist.
Although excessive amounts of carbon dioxide in the atmosphere can contribute to global warming and climate change, it is still essential in appropriate quantities for the survival of plants and the overall balance of the Earth's ecosystems.