Perspex and polythene are good examples of insulators.
Answer:
30 moles of CO₂
Explanation:
balanced equation ,
CS₂+3O₂ → CO₂+2SO₂
From equation, 3 moles of O₂ are needed to make 1 mol of CO₂.
This means to produce 1 mol of CO₂, we need 3 moles of O₂, then how many moles of CO₂ will be produced from 90 moles of O₂ ?
Use unitary method to solve such problems,
Number of moles of CO₂ that will be produced:
= 
=
= 30 moles of CO₂
Answer:
D) Rate = K [NO2][Cl2]
Explanation:
2 NO2 + Cl2 → 2 NO2Cl (overall reaction)
NO2 + Cl2 → NO2Cl + Cl (slow)
NO2 + Cl → NO2Cl (fast)
The rate-determining step is the slowest step in a reaction mechanism. Because it is the slowest, it determines the rate of the overall reaction.
Rate of reaction is typically given as;
Rate = K [Reactants]
In the slow step i the reaction mechanism, the reactants are; NO2 and Cl2. Since both are not intermediates, there is no need for further working out.
Rate = K [NO2][Cl2]
The protons are equivalent to the atomic number, so we can determine that the element being expressed here is Magnesium. If you are ever stuck on what element you are finding your information from, just remember that the number of protons is the exact same as the atomic number in ANY situation :)
The charge of magensium is +2, with an atomic mass of 24. So A would be your answer :)
Chemical reaction: Sr(OH)₂ + 2HNO₃ → Sr(NO₃)₂ + 2H₂O.
part A) m(Sr(OH)₂) = 21,78 g.
n(Sr(OH)₂) = m(Sr(OH)₂) ÷ M(Sr(OH)₂).
n(Sr(OH)₂) = 21,78 g ÷ 87,62 g/mol.
n(Sr(OH)₂) = 0,248 mol.
c(Sr(OH)₂) = n(Sr(OH)₂) ÷ V(Sr(OH)₂).
c(Sr(OH)₂) = 0,248 mol ÷ 0,075 L.
c(Sr(OH)₂) = 3,3 mol/L.
part B) V(Sr(OH)₂) = 34,21 mL = 0,03421 L.
n(Sr(OH)₂) = 0,03421 L · 3,3 mol/L = 0,112 mol.
From chemical reaction: n(Sr(OH)₂) : n(HNO₃) = 1 : 2.
n(HNO₃) = 0,225 mol.
V(HNO₃) = 0,225 mol ÷ 0,25 mol/L.
V(HNO₃) = 0,9 L = 900 ml.
