### Organic Chemistry Calculations, Significant Digits

The key terms of this Chemistry quiz include Significant Digits, Organic Chemistry Calculations.

Add or subtract the following measurements. Be sure each answer you enter contains the correct number of significant digits.

**Answer**

**13.60 g + 1.0 g = 14.6 g**

**60.80 g – 1.470 = 15.33 g**

**13.620 g – 0.7 g = 12.9 g**

Multiply or divide the following measurements. Be sure each answer you enter contains the correct number of significant digits.

How many protons are in a neutral atom of chlorine? How many electrons?

**Answer**

**Number of protons = 17**

**Number of electrons = 17**

The energy E of the electron in a hydrogen atom can be calculated from the Bohr formula:

E = – R_{y}/n^{2}

In this equation R_{y } stands for the Rydberg energy, and n stands for the principal quantum number of the orbital that holds the electron.

Calculate the wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron from an orbital with n = 9 to an orbital with n = 9. Round your answer to 3 significant digits.

**Answer**

**384 nm**

**Alternate answer**

**383. nm**

#### Significant Digits – Organic Chemistry Quiz

Fill in the missing information:

It takes 412. kJ/mol to break a carbon-hydrogen single bond. Calculate the maximum wavelength of light for which a carbon-hydrogen single bond could be broken by absorbing a single photon.

Be sure your answer has the correct number of significant digits.

**Answer **

**291 nm**

**Alternate answer**

**290. nm**

The energy E of the electron in a hydrogen atom can be calculated from the Bohr formula:

E = – R_{y}/n^{2}

In this equation R_{y } stands for the Rydberg energy, and n stands for the principal quantum number of the orbital that holds the electron.

Calculate the wavelength of the line in the emission line spectrum of hydrogen caused by the transition of the electron from an orbital with n = 9 to an orbital with n = 9. Round your answer to 3 significant digits.

**Answer**

**384 nm**

**Alternate answer**

**383. nm**

Add or subtract the following measurements. Be sure each answer you enter contains the correct number of significant digits.

**Answer**

**13.60 g + 1.0 g = 14.6 g**

**60.80 g – 1.470 = 15.33 g**

**13.620 g – 0.7 g = 12.9 g**