An anion is an ion with a negative charge. The minus sign, when attached to the end of an ionic compound, indicates that this has a negative charge, while a plus sign indicates a positive charge.
O2- is the only compound listed that satisfied this. It is the anion.
Answer is 02-
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Answer:
±0.005 g
Explanation:
The uncertainty depends on whether the measurement was obtained manually or digitally.
1. Manual
The minimum uncertainty is ±0.01 g.
It may be greater, depending on random or personal errors
2. Digital
Most measurements of mass are now made on digital scales.
A digital device must always round off the measurement it displays.
For example, if the display reads 20.00, the measurement must be between 20.005 and 19.995 (±0.005).
If the measured value were 20.006, the display would round up to 20.01.
If the measured value were 19.994, the display would round down to 19.99.
The uncertainty is ±0.005 g.
The scale shown below would display a mass of 20.00 g
Answer:
ΔH°_rxn = -195.9 kJ·mol⁻¹
Explanation:
4NH₃(g) + 3O₂(g) ⟶ 2N₂(g) +6H₂O(g)
ΔH°_f/(kJ·mol⁻¹): -45.9 0 0 -241.8
The formula relating ΔH°_rxn and enthalpies of formation (ΔH°_f) is
ΔH°_rxn = ΣΔH°_f(products) – ΣΔH°_f(reactants)
ΣΔH°_f(products) = -6(241.8) = -1450.8 kJ
ΣΔH°_f(reactants) = -4(45.9) = -183.6 kJ
ΔH°_rxn = (-1450.8 + 183.6) kJ = -1267.2 kJ