Answer:
The missing information or their role in the discovery of the cell is as follows:
Robert Hooke: He was the first scientist to called cells to tiny box-like cavities he saw in cork and illustrated as cells.
A. Leeuwenhoek: he was a microscopist and microbiologist who used microscopes and observed many other living cells. He called animalcules to these single-cell living organisms later used to prove that cells are the fundamental unit of life.
Schwann and Schleiden: They presented the theory that suggested that the cells are basic building blocks of all living things.
Virchow: He observed that the cell dividing and come from pre-existing cells.
No, since they are the strongest type of ray only elements that are dense can block them.
Full Question:
Ammonia chemically reacts with oxygen gas to produce nitric oxide and water. What mass of water is produced by the reaction of 7.7g of ammonia?
Be sure your answer has the correct number of significant digits.
Answer:
12.23g ≈ 12g (2 s.f)
Explanation:
Ammonia chemically reacts with oxygen gas to produce nitric oxide and water. The balanced chemical reaction is given as:
4 NH3 + 5 O2 -------> 4 NO + 6 H2O
From the reaction;
4 mole of ammonia reacts to produce 6 moles of water
From the question;
Moles = mass / molar mass
From the question;
moles of ammonia = mass / molar mass = 7.7 / 17 = 0.4529moles
Number of moles of water produced;
4 = 6
0.4529 = x
x = (0.4529 * 6 ) / 4
x = 0.67935moles
Mass of water = moles * molar mass = 0.67935 * 18 = 12.23g ≈ 12g (2 s.f)
A pure substance<span> has a definite and constant composition. A pure substance can be either an element or a compound, but the composition of a pure substance doesn’t vary.</span> Ex: salt or sugar<span>
</span>Mixtures are physical combinations of pure substances that have no definite or constant composition — the composition of a mixture varies according to who prepares the mixture. Ex: sand mixed with salt
