Asample of a solid labeled as nacl may be impure. a student analyzes the sample and determines that it contains 75 percent chlorine by mass. pure nacl contains 61 percent chlorine by mass. which of the following statements is consistent with the data?
a- the sample contains only nacl
b- the sample contains nacl and nai
c- the sample contains nacl and kcl
d- the sample contains nacl and licl

The impure sample contains a mixture of NaCl and LiCl.

WHAT IS A PURE SUBSTANCE?

A pure substance is that substance that contains a fixed or constant chemical composition.

According to this question, a pure composition of NaCl contains 61 percent chlorine by mass. However, the solid sample in this question contains 75 percent chlorine by mass. This means that an impurity that increased the chlorine content (KCl or LiCl) is present in the sample.

Therefore, impure sample contains a mixture of NaCl and LiCl.

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what is the question?

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.