Chemistry Answers

The bond energy of F₂ is unusually low, in comparison with the other halogens, due to the small size of the fluorine atom. Which of the following periodic properties is also unusually low in the case of fluorine?

if 3.00 grams of H₂ were produced, how many grams of Al reacted?

1. Calculate the pH of the original buffer solution of dihydrogen phosphate/hydrogen phosphate.

2. Calculate the pH The 20 mL (dihydrogen phosphate/hydrogen phosphate buffer) solution when 1 mL of 0.1 molL-1 NaOH has been added

3. Calculate the pH of the 20 mL (dihydrogen phosphate/hydrogen phosphate buffer) solution when 1 mL of 0.1 molL-1 HCl has been added

- Using the Henderson formula for the pH of a solution: pH = pKa + log ([A-]/ [HA]), and show working out

For each of the following molecules, write the Lewis structure(s), predict the molecular structure (including bond angles), give expected hybrid orbitals on the central atom, and predict the overall polarity.

a. OF2 b. AsF5 c. IF5

6.) 10.1 how many significant figures?

a. 3

b. 2

c. 1

7.) 0.0004 how many significant figures?

a. 4 b. 3 c. 1

8.) 1 cm converts into m

a. 10mm b. 100mm c.1000mm

9.) 100 cm converts into m

a. 1m b.10m c.0.1m

10.) 1km to m

a. 10m b. 100m c. 1000m

11.) 1000 grams to kilogram

a. 0.1kg b. 10kg c. 1kg

12.) 1L to ml

a. 10ml b. 100ml c.1000ml

Matching Type:

A.

1.) 3.005 g

2.) 820 m

3.) 0.000 670 km

4.) 0.405 021 kg

5.) 22.4 L

B.

a. 4 significant figures

b. 2 significant figures

c. 3 significant figures

d. 6 significant figures

e. 3 significant figures

1.) 300 convert into scientific notation

a. 3x10^2

b. 3.00x10^1

c. 3.00x10

2.) 4x10^3 convert into ordinary decimal notation

a. 4000

b. 400

c. 40 000

3.) 48,923 how many significant figures?

a. 5

b. 4

c. 3

4.) 900.06 how many significant figures?

a. 5

b. 4

c. 3

5.) 3,000,000 how many significant figures?

a. 1

b. 7

c. 6

Convert the measuring units as indicated.

1.) 2.25 gal=__________qt

2.) 4.453 km=_________

3.) 103 in=_________ft

4.) 42 oz=_________gal

5.) 1.3 T=_________Ib

6.) 5078 m=_________km

1.) 52140 ft=__________mi

2.) 24 oz=__________qt

3.) 3 pt=___________ c

4.) 3.5 qt=__________oz

5.) 10300 lb=_________T

1.) 1.336 gal=_________ oz

2.) 5 c=__________ oz

3.) 72 oz=_________qt

4.) 5.8 T=__________ lb

5.) 2.25 lb=__________ oz

6.) 0.875 qt=__________ oz

Convert each of the following into scientific notation.

1. 3427

2. 172

3. 3100.0x10²

4. 0.0000455

5. 0.982 x 10-³

6. 3.03x10-¹

7. 0.00565

8. 1000x10-³

9. 0.00456

10.0.000984

Determine the number of the significant figures in each of the following.

1. 3427

2. 172

3. 3100.0x10²

4. 0.0000455

5. 0.982 x 10-³

6. 3.03x10-¹

7. 0.00565

8. 1000x10-³

9. 0.00456

10.0.000984

A new sunscreen has been developed that is supposed to be more effective at preventing sunburn. 30 participants spray one arm with the new formula ,and spray the other arm with the leading formula. After 4 hours in the sun, their skin is evaluated for any redness

the production of 2.0 moles of HCl would require 70. grams of Cl₂ and —