Always remember that a compound can be separated into simpler substances by chemical methods/reactions. While elements cannot be broken down into simpler substances by chemical reactions. You can do a flame test and spectrum analysis to determine whether a solid material is an element or a compound. Check the boiling and/or melting point, color or density. Also check the solid material’s reaction with oxygen, hydrogen, calcium, or various acids. Examine and study its physical chemistry. The element(s) that may be present may be identified by checking the absorption edges from an x-ray spectrum.
Answer: 0.86g/mL
Explanation:
Mass of empty cylinder = 23.731g
Mass of cylinder + liquid = 26.414g
Mass of the liquid = 26.414 — 23.731
= 2.683g
Volume of the liquid = 3.12mL
Density = Mass / volume
Density = 2.683g / 3.12mL
Density = 0.86g/mL
Plants maintain water balance by opening and by closing stomata.
Explanation:
When plants are not getting enough water the tips as well as the edges of the leaves start drying and ultimately it turns brown in color. And when all the leaves turn brown the plant ultimately dies.
When light is travelling from the air to the water , the movement slows down and thus there is a little change in the direction. Thus we can say a light bend occurs when the light moves towards denser medium.
Answer:
Option A.
Explanation:
1 mol of anything contains 6.02×10²³ particles.
We know that 1 mol of oxygen gas contains 2 moles of O.
1 mol of oxygen weighs 16 g/mol, the mass for 1 molecule of O.
By the way, the mass for 1 mol of O₂ may be:
Option A → 16 g/mol . 2 mol
32 g
Oyxgen is a dyatomic molecule, that's why we have 2 moles of O.
Another example can be:
1 mol of water (H₂O) contains 2 moles of H and 1 mol of O.
