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Chemistry / Chemie - 124

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When 11 g NaOH dissolves in 249 g of water in a coffee-cup calorimeter, ΔH = −42.6 kJ/mol. The temperature increases from 18.4 °C to X °C. What is the value of X?

(Assume that the solution has the same specific heat as liquid water, i.e., 4.18 J/g°C)

Wanneer 11 g NaOH in 249 g van water in 'n koffie-beker kalorimeter opgelos word, is ΔH = −42.6 kJ/mol. Die temperatuur styg van 18.4 °C tot X °C. Wat is die waarde van X?

(Aanvaar dat die oplossing dieselfde spesifieke warmte het as vloeibaar water, dit wil sê, 4.18 J/g°C)

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If 180.8 J are required to change the temperature of 15.31 g of a substance from 21.1 °C to 31.2 °C, what is the specific heat capacity of the substance?

Indien 180.8 J nodig is om die temperatuur van 15.31 g van 'n stof vanaf 21.1 °C tot 31.2 °C te verander, wat is die spesifieke warmtekapasiteit van die stof?

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A sample of 2.1 moles of ethanol (C₂H₅OH) is initially at 20.0 °C. If the sample absorbs 2.8 kJ of heat, determine the final temperature of the ethanol.

(C_ethanol= 2.46 J g^-1 °C^-1).

‘n Monster van 2.1 mol etanol (C₂H₅OH) is aanvanklik by 20.0 °C. Indien die monster 2.8 kJ warmte absorbeer, bepaal die finale temperatuur van die etanol.

(C_etanol = 2.46 J g^-1°C^-1)

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Methanol (CH₃OH) is an efficient fuel with a high octane rating. It undergoes combustion as follows:	Metanol (CH₃OH) is 'n doeltreffende brandstof met 'n hoë oktaangradering.Dit ondergaan verbranding soos volg:
2 CH₃OH (g) + 3 O₂ (g) → 2 CO₂ (g) + 4 H₂O (l) ; ΔH = -1528 kJ
What mass of O₂ (g) is consumed when 768 kJ of heat are evolved?	Watter massa O₂ (g) word verbruik as 768 kJ warmte ontwikkel word?

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Ammonia reacts with oxygen as follows. Determine the enthalpy change (kJ) for the production of 4.70 g of NO₂(g).

Ammoniak reageer met suurstof soos volg. Bepaal die entalpieverandering (kJ) vir die produksie van 4.70 g NO₂(g).

4 NH₃(g) + 7 O₂(g) → 4 NO₂(g) + 6 H₂O(g) ΔH = -1389 kJ

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Hydrazine (N₂H₄) is a liquid often used as rocket fuel. Upon combustion, it yields nitrogen gas and liquid water.

If a 16.6 g sample of N₂H₄ evolves 1411.2 kJ of heat during combustion, calculate the molar enthalpy change for the combustion of hydrazine?

Hidrasien (N₂H₄) is 'n vloeistof wat dikwels as vuurpylbrandstof gebruik word. Tydens verbranding lewer N₂H₄stikstofgas en water (vloeistoffase).

Indien 'n 16.6 g monster van N₂H₄ 1411.2 kJ warmte tydens verbranding ontwikkel, bereken die molêre entalpieverandering vir die verbranding van hidrasien.

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P-V work (w = -PΔV) occurs in the following system. Assuming all gases are ideal such that PΔV = ΔnRT, determine the amount of work done (in J) with respect to the system at 323 K. (R = gas constant = 8.314 J/mol·K)	P-V werk (w = -PΔV) vind plaas in die volgende sisteem. Gestel dat alle gasse ideaal is sodat PΔV = ΔnRT en bepaal dan die hoeveelheid werk (in J) wat in die sisteem gedoen word by 323 K. (R = gaskonstante = 8.314 J/mol·K)
N₂O₄ (g) → 2 NO₂ (g)

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The value of ΔH° for the reaction below is −142 kJ. What amount of heat is transferred when 40.5 grams of HBr are formed in this reaction?

Die waarde van ΔH° vir die reaksie hieronder is −142 kJ. Hoeveel warmte word oorgedra wanneer 40.5 g HBr in hierdie reaksie gevorm word?

H₂(g) + Br₂(g) → 2 HBr(g)

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Nitrogen gas (N₂) reacts with a metal to form a compound in which there are three atoms of the metal for each atom of nitrogen. If 1.485 g of the metal reacts with 1.08 g of nitrogen gas to form only this compound, what is the calculated atomic mass of the metal?

Please give your answer with the correct number of significant figures.

Stikstofgas (N₂) reageer met 'n metaal om 'n verbinding te vorm waarin daar drie atome van die metaal vir elke stikstofatoom is. As 1.485 g van die metaal met 1.08 g stikstofgas reageer om slegs dié verbinding te vorm, wat is die berekende atoommassa van die metaal?

Gee asb jou antwoord met die korrekte aantal beduidende syfers.

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Heroin has the molecular formula C₂₁H₂₃NO₅. What mass in g of CO₂ will be produced from combustion analysis of a 38.74 mg sample of heroin?

Please give your answer to the correct number of significant figures.

Heroïen het die molekulêre formule C₂₁H₂₃NO₅. Watter massa in g van CO₂ sal geproduseer word tydens die verbrandingsanalise van 'n 38.74 mg monster heroïne?

Gee asseblief jou antwoord met korrekte aantal beduidende syfers.

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