Science Chapter 4 Section 2

How many moles does 11 g of silicon, Si, contain?

0.30

What is the mass in grams of 0.49 mol of platinum, Pt?

93.6

How many moles does 205 g of helium, He, contain?

51.25

What is the mass in grams of 3.1 mol of mercury, Hg?

621.82

Calculate the number of neutrons that each of the following isotopes contain. Use the periodic table to find the atomic numbers.

A. Atomic number is 6. Number of neutrons is 14. 14-6=8 B.atomic number is 7. Number of neutrons is 15. 15-7=8 C. Atomic number is 16. Number of neutrons is 35. 16-35=18 D.atomic number is 20. Number of neutrond is 45. 45-20=25

Determine the molar mass of each of the elements.

A. Manganese- 54.9 B. Cadmium- 112.411 C. Arsenic- 74.92 D. Strontium- 87.62

Identify the unit that is used for atomic masses.

AMU

Explain how you can use an atomic mass number and atomic number to determine the number of protons, electrons, and neutrons in the atom.

Atomic number is equal to the number of protons in the atom.

Define Avogadro's number, and describe how it relates to a mole of a substance.

Avogadro's number is the number of units required to substance.

Explain why the mass of atoms of the same element may be different.

Presence of different number of neutrons.

Identify the subatomic particle used to define an element, and explain why this particle is used.

Proton is the subatomic particle which is used to define an element becasue it is unique. No two elements have same number of protons.

Which has a greater number of atoms: 3.0 g of iron, Fe, or 2.0 g of sulfur, S?

Surfer

Predict which isotope of nitrogen is more common in nature: nitrogen-14 or nitrogen-15.

The average is closer to nitrogen 14. Meaning nitrogen 15 is more rare.

A graph f the amount of a particular element in moles versus the mass of the element in grams is a straight line. Explain why.

There is a straight line

If an atom loses electrons, will it have an overall charge?

Yes. All the atoms are electrically neutral in their ground state. But when an atom loses its electron there will be an overall charge of positive on the atom as there are less number electrons compared to the number of protons which are positively charged.

List the charge, mass, and location of each of the 3 subatomic articles found in atoms.

mass number the sum of the numbers of protons and neutrons in the nucleus of an atom. Atomic number is the number of protons