Answer:
It is pseudoscience because there are at least 118 known elements in nature.
Explanation:
Alchemy is an ancient branch of natural philosophy (not used much anymore).
I also just took the test and it's correct.
Answer:
Here are some of the differences between a mixture of iron and sulfur, and iron sulfide: the mixture can contain more or less iron, but iron sulfide always contains equal amounts of iron and sulfur. the iron and sulfur atoms are not joined together in the mixture, but they are joined together in iron sulfide.
Explanation:
Answer:- Mass of the alloy is 2.8 kg.
Solution:- Mass of Cr in the alloy is 325 g and mass of Fe in the alloy is 2.5 kg. Mass of alloy would be the sum of masses of constituent metals.
Masses of the metals are not in the same units. So, we need to make the units equal. The want answer in kg so let's convert mass of Cr from g to kg.
Since, 1000 g = 1 kg
So, 
= 0.325 kg
Mass of alloy = mass of Cr + mass of Fe
mass of alloy = 0.325 kg + 2.5 kg = 2.825 kg
If we consider significant figures then as per the rules, the answer should not have more than one decimal place.
So, 2.825 kg is round off to 2.8 kg and hence the mass of the alloy is 2.8 kg.
The balanced chemical reaction describing this decomposition is as follows:
<span>4c3h5n3o9 .............> 6N2 + 12CO2 +10H2O + O2
From the periodic table:
mass of oxygen = 16 grams
mass of nitrogen = 14 grams
mass of hydrogen = 1 gram
mass of carbon = 12 grams
Therefore:
mass of </span><span>C3H5N3O9 = 3(12) + 5(1) + 3(14) + 9(16) = 227 grams
mass of O2 = 2(16) = 32 grams
From the balanced chemical equation:
4(227) = 908 grams of </span>C3H5N3O9 produce 32 grams of O2. Therefore, to know the amount of oxygen produced from 4.5*10^2 grams <span>C3H5N3O9, all we need to do is cross multiplication as follows:
amount of oxygen = (4.5*10^2*32) / (908) = 15.859 grams</span>
Im unsure :( maybe try looking up a calorie calculator
