Suppose a New Metallic Element X Is Discovered, and Its

question 135

Multiple Choice

Suppose a new metallic element X is discovered, and its reactions with oxygen gas and chlorine gas at 298 K are studied. However, it is later discovered that one of the samples was contaminated, and the ΔHº_rxn value from this trial is not reliable. Which trial had the contaminated sample, and what should the correct value of ΔHº_rxn be for this trial?

• A) Trial 1 had the contaminated sample; its ΔHº_rxn value should be -900 kJ/mol.
• B) Trial 2 had the contaminated sample; its ΔHº_rxn value should be +100 kJ/mol.
• C) Trial 3 had the contaminated sample; its ΔHº_rxn value should be -1000 kJ/mol.
• D) Trial 3 had the contaminated sample; its ΔHº_rxn value should be +1000 kJ/mol.
• E) Not enough information is provided; all three trials must be redone.

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Definitions:

Normal Distribution

Refers to a probability distribution that is symmetric around the mean, showing that data near the mean are more frequent in occurrence than data far from the mean.

Z-score

A statistical measurement that describes a value's relationship to the mean of a group of values, normalized to standard deviation units.

Normal Random Variable

A variable that follows a normal distribution, characterized by its mean and standard deviation, representing outcomes with a probabilistic nature.

Standard Deviation

An assessment of the extent to which values in a set are dispersed or varied from the mean, highlighting the differences from the average.