I'm not entirely sure but i think it's Se2-
Answer:
0.6 grams of hydrogen are needed to react with 2.75 g of nitrogen.
Explanation:
When hydrogen and nitrogen react they form ammonia.
Chemical equation:
N₂ + 3H₂ → 2NH₃
Given mass of nitrogen = 2.75 g
Number of moles of nitrogen:
Number of moles = mass/ molar mass
Number of moles = 2.75 g / 28 g/mol
Number of moles = 0.098 mol
Now we will compare the moles of nitrogen with hydrogen from balance chemical equation:
N₂ : H₂
1 : 3
0.098 : 3×0.098 = 0.3 mol
Mass of hydrogen:
Mass = number of moles × molar mass
Mass = 0.3 mol × 2 g/mol
Mass = 0.6 g
The molecular mass of carbon monoxide (CO) is 28 g/mol
<u><em>calculation</em></u>
The molecular mass of CO = atomic mass of C + atomic mass of O
From periodic table the atomic mass of C = 12 g/mol and for O = 16 g/mol
Therefore the molecular mass of Co = 12 g/mol + 16 g/mol = 28 g/mol
<span>A) 2NaOH -> 2Na + O2 + H2
is not correct since Na is unstable
B) 2NaOH -> 2Na + H2O + 1/2O2
is not correct since Na is unstable
C) 2NaOH -> Na2O + H2O
is correct since N2O is stable
D) 2NaOH -> 2Na + H2O2
is not correct since Na is unstable</span>
HISTORICAL INTRODUCTION.1<span> EVER since the establishment of the atomic theory by Dalton and Berzelius it was felt among chemists that there must be some relation between the atomic weights of the different elements and their properties. It was recognized very early that there exist groups of elements possessing related chemical and physical properties, and one of the earliest attempts to bring out this point is due to Dobereiner. In 1829 he tried to show that “many elements may be arranged in groups ()f three, in each of which the middle element has an atomic weight equal or approximately equal to the mean of the atomic weights of the two extremes.” As illustrations of this method of arrangement may be mentioned the following groups: Li, Na, K; Ca,Sr,</span>
