Question

There are 7.11 x1024molecules in 100.0 cm3of a certain substance.a. What is the number of molecules in 1.09 cm3of the substance?7.75 x 1022moleculesb.What is the number of molecules in 2.24 x 104cm3of the substance?1.59 x 10 27moleculesc. What number of molecules would be in 9.01 x 10-6cm3?6.41 x 1017molecules

Answer 1

Calculating the number of particles in a given volume involves using Avogadro's number and proportionality between the volume and the number of particles, assuming constant density.

Step-by-step explanation:

The question involves concepts from chemistry, specifically dealing with Avogadro's number, the mole, and calculations of the number of molecules in a given volume. Avogadro's number is defined as the number of atoms or molecules in one mole of a substance, which is 6.022 × 10²23. When given the number of molecules in a specific volume, you can calculate the number of molecules in a different volume by setting up a proportional relationship. This is because the number of molecules is directly proportional to the volume if the density remains the same.

For example, if there are 7.11 × 10²24 molecules in 100.0 cm³ of a substance, to find the number of molecules in 1.09 cm³:

• Set up a proportion: (7.11 × 10²24 molecules / 100 cm³) = (x molecules / 1.09 cm³)
• Solve for x to find the number of molecules in 1.09 cm³.

Similarly, you would use the same approach for other volumes to determine the number of molecules in 2.24 × 10²4 cm³ and 9.01 × 10²²6 cm³ respectively.

Answer 2

a. 7.75 × 10²² molecules

b. 1.59 × 10²⁷ molecules

c. 6.41 × 10¹⁷ molecules

Step-by-step explanation:

There are 7.11 × 10²⁴ molecules in 100.0 cm³ of a certain substance. We will use this ratio in our conversion fractions.

a. What is the number of molecules in 1.09 cm³ of the substance?

1.09 cm³ × (7.11 × 10²⁴ molecules/100.0 cm³) = 7.75 × 10²² molecules

b. What is the number of molecules in 2.24 × 10⁴ cm³ of the substance?

2.24 x 10⁴ cm³ × (7.11 × 10²⁴ molecules/100.0 cm³) = 1.59 × 10²⁷ molecules

c. What number of molecules would be in 9.01 × 10⁻⁶ cm³?

9.01 × 10⁻⁶ cm³ × (7.11 × 10²⁴ molecules/100.0 cm³) = 6.41 × 10¹⁷ molecules