The mass of a solid copper penny is 3.46 g. how many copper atoms are in the penny?

n° atoms = 3.275x10²² atoms

Explanation:

To do this, we need to use the molecular weight of the copper, which is 63.55 g/mol.

Now, to know the number of atoms of any compound, we use the avogadro number which is relationed to the number of moles of any compound so:

1 mol = 6.02x10²³ atoms

In order to know the atoms, we need to calculate the moles of copper with the following expression:

n = m/MW

Doing so, we have the moles, and then, use the avogadro number to calculate the atoms:

First the moles:

n = 3.46/63.55 = 0.0544 moles

Now, let's calculate the atoms:

n° atoms = n * Av. number

n° atoms = 0.0544 ¨* 6.02x10²³

n° atoms = 3.275x10²² atoms

This would be the atoms in the penny.

answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.  

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.