Answer:
Explanation:
Mole = no. Molecules/6.02×10^23
Mole = (1.40×10^24)/(6.02×10^23)
Mole = 2.33mole
Answer:
305 litres of NO gas will be produced from 916 L of NO₂
Explanation:
Given the balanced equation of the chemical reaction as follows:
3 NO₂ (g) + H₂O( l) —— 2 HNO₃ (l) + NO (g)
Under standard conditions, 3 moles of No₂ will react with 1 mole of water to produce 1 mole of NO gas.
Molar volume of a gas at STP is 22.4 L
Number of moles of NO₂ gas present in 916 L = 916/22.4 = 40.893 moles of NO₂ gas
From the mole ratio of NO₂ to NO in the equation of reaction,
Number of moles of NO that will be produced = 1/3 × 40.893 moles = 13.631 moles of NO gas
Volume of 13.631 moles of NO gas = 13.631 × 22.4
Volume of NO gas produced = 305.334L
Therefore, Volume of NO gas produced from the reaction of 916 L of NO₂ with water = 305 L
Answer:
- <em><u>Mendeleev produced the first orderly arrangement of known elements.</u></em>
- <em><u>Mendeleev used patterns to predict undiscovered elements.</u></em>
Explanation:
- <u>Mendeleev produced the first orderly arrangement of known elements and used patterns to predict the undiscovered elements.</u>
Those two statments are true.
For the time being there were some 62 known elements. Before Medeleev some schemes to order part of the elements were proposed, but Medeleev showed the relationship between the atomic mass and the properties of the elements (supports second choice). This arrangement is known as the periodic table.
More importantly, Mendeleev predicted correctly the existance and properties of unknown elements, which is his major contribution: he left blanket spaces which where gradually filled when new elements where discovered (this supports the fourth choice).
The first modern chemistry book was written by Antoine Lavoisier (this discards first option).
Mendeleev ordered the elements by increasing mass number (this discards third choice), which was corrected later by the scientist Henry Moseley, who ordered the elements by increasing atomic number (number of protons).
Isotopes were not known by Mendeleev times, so this discards the last option.
