In the lime soda process once used in large scale munici-pal water softening, calcium hydroxide prepared from lime and sodium carbonate are added to precipitate Ca2+ as CaCO3(s) and Mg2+ as Mg(OH)2(s): Ca2+(aq) + CO32-(aq) → CaCO3(s) Mg2+(aq) + 2 OH-(aq) → MgOH2(aq) How many moles of Ca(OH)2 and Na2CO3 should be added to soften (remove the Ca2+ and Mg2+) 1200 L of water in which [Ca2+] = 5.0x10-4 M and [Mg2+] = 7.0x10-4 M?
Ch.18 - Chemistry of the Environment
18장, 문제 49
The organic anion

is found in most detergents. Assume that the anion under-goes aerobic decomposition in the following manner: C18H29SO3- + 51 O2 → 36 CO2(aq) + 28 H2O (l) + 2 H+(aq) + 2 SO42-(aq) What is the total mass of O2 required to biodegrade 10.0 g of this substance?
검증된 단계별 안내1
Step 1: Write down the balanced chemical equation for the decomposition reaction: C18H29SO3- + 51 O2 → 36 CO2(aq) + 28 H2O (l) + 2 H+(aq) + 2 SO42-(aq).
Step 2: Calculate the molar mass of the organic anion C18H29SO3-. Use the atomic masses: C (12.01 g/mol), H (1.01 g/mol), S (32.07 g/mol), and O (16.00 g/mol).
Step 3: Determine the number of moles of the organic anion in 10.0 g by dividing the mass by the molar mass calculated in Step 2.
Step 4: Use the stoichiometry of the balanced equation to find the moles of O2 required. According to the equation, 1 mole of C18H29SO3- reacts with 51 moles of O2.
Step 5: Calculate the total mass of O2 required by multiplying the moles of O2 (from Step 4) by the molar mass of O2 (32.00 g/mol).

비슷한 문제에 대한 검증된 영상 답변:
이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m주요 개념
질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.
Stoichiometry
Stoichiometry is the calculation of reactants and products in chemical reactions. It involves using balanced chemical equations to determine the relationships between the quantities of substances involved. In this case, stoichiometry will help calculate the amount of O2 needed to completely react with a given mass of lauryl sulfate based on the provided reaction.
추천 영상:
가이드 코스
Stoichiometry Concept
Molar Mass
Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is essential for converting between the mass of a substance and the number of moles, which is necessary for stoichiometric calculations. For lauryl sulfate (C18H29SO3-), knowing its molar mass allows us to determine how many moles correspond to the 10.0 g given in the question.
추천 영상:
가이드 코스
Molar Mass Concept
Aerobic Decomposition
Aerobic decomposition is the breakdown of organic matter by microorganisms in the presence of oxygen. This process results in the production of carbon dioxide, water, and other byproducts. Understanding this concept is crucial for interpreting the reaction provided, as it highlights the role of O2 in the biodegradation of lauryl sulfate and the overall environmental impact of detergents.
추천 영상:
가이드 코스
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