NUTRITIONAL FACTS PROBLEMS

Nutrition Facts  
Serving size 100 grams
Amount per serving
Calories?  
                                      % Daily Value
Total Fat 22 g               33%
Saturated Fat 10 g          50%

Cholesterol 80 mg         26%
Sodium 54 mg               2%

Carbohydrates 0 g         0%
Dietary Fiber 0 g           0%
Sugars 0 g

Protein 24 g                  48%

QUESTIONS:

1. Estimate the number of Calories per serving from the above food label.

A. 194 cal

B. 160 cal

C. 294 cal

D. 400 cal

2. Which of the following foods is the most likely source of this label?

A. strawberry

B. Butter

C. Steak

D. Oatmeal

ANSWERS:

1. C  (Use the fact that carbohydrate generates 4 cal/gram; fat 9 cal/gram; and proteins 4 cal/gram)

2. C

QUESTION FOR THE DAY

1. A child who is 7 years old, lifts a 40 kg-bag from the floor onto a table that is 3-feet high from the floor. If an adult, who is 25 years old lifts the same bag from the floor onto the same table, who do you think has done more work?

A. The child

B. The adult

C. Both did the same amount of work

D. No work is done

2. A child who is 7 years old, lifts a 40 kg-bag from the floor onto a table that is 3-feet high from the floor. If an adult, who is 25 years old lifts the same bag from the floor onto the same table, who do you think put in more energy?

A. The child

B. The adult

C. Both did the same amount of work

D. No work is done

ANSWERS

Work is defined as the force times the distance through which it acts.

Work = Force x Distance

1. C The force is derived from the mass of the bag which is its weight. Remember F = mg. That is, Force = mass x acceleration due to gravity. Since they lift the same weight through the same distance of 3 feet onto the table, the work done by both of them is the same.  

2. A The work done is the same but the child puts in more energy to do the same amount of work. Energy is the ability to do work.

TAKE A VACATION TRIP TO RELAX THE BRAINS

For those who want to take  a great vacation, one of the best places you would not regret visiting is the state of California, USA. Check out this blog to see what you would experience. Click here!

OVERVIEW OF TOPICS COVERED IN THIS BLOG

If you have just stumbled on this page by chance, YOU ARE WELCOME! The are many topics covers in this blog. You can do a search on the blog using various phrases or subject matter. Here is a summary of some of the topics covered.

Lesson 1:	Basic structure of atom Cell structure and function Functions of cell organelles Types of tissues
Lesson 2:	Movement of substances across the cell membrane Acids and bases, pH scale Carbohydrates, proteins, lipids and nucleic acids
Lesson 3:	Basic structure of the eye Basic structure of the ear Nervous system
Lesson 4:	Circulatory system Introduction to mechanics (motion/forces) Electrical circuits
Lesson 5:	Balancing chemical equations and writing formulas Essentials of photosynthesis and respiration Classifying organic compounds Magnetism Electromagnetism
Lesson 6:	Interpretation of graphs and pictograms Analyzing and making conclusions from experiments Data analysis
Lesson 7:	Endocrine system Digestive system Genitourinary system
Lesson 8:	Reproduction in mammals Basic parts of a flower Reproduction in plants (the process of pollination Genetics
Lesson 9:	Modes of heat transfer Calculating heat energies and phase diagrams Temperature conversions (Kelvin, Celsius, Fahrenheit)
Lesson 10:	Gas laws (Boyle, Charles, Gay-Lussac) Types of energy (Potential, kinetic, etc…..) Chemical bonds, equilibrium and equilibrium constants Mixtures, types of solutions, solubility
Lesson 11:	Concepts of the food pyramid, food web and food chain Light (diffraction, refraction, reflection, dispersion) Basic concepts on waves Sound waves Catalyst and enzymes
Lesson 12:	Symbiosis Ecology The Electroscope Radioactivity and half-life Tropism Tropism

RELATIVE ATOMIC MASS QUESTIONS

Question 1:
Calculate the relative atomic mass of silver if it occurs naturally as 51.84% silver-107 and 48.18% silver-109.

Solution:
Relative atomic mass = 0.5184 (107) + 0.4816 (109)
Relative atomic mass = 107.96

Question 2:
Calculate the relative abundance of each isotope of copper if it consists of two isotopes, copper-63 and copper-65. Its relative atomic mass is 63.62.

Solution:
Let Abundance of copper-63 = x
Then, Abundance of copper-65 = 1-x

Relative atomic mass = 63x + 65(1-x)
                                      63x + 65(1-x) = 63.62
                                       x = 0.69
That is, 69% of copper-63 and 31% of copper-65

THE MASS SPECTROMER

The mass spectrometer is an instrument used for analyzing samples of elements and compounds. It consists of six basic stages: Injection, Vaporization,  Ionization, Acceleration, Deflection, and  Detection.

Click to view a diagram of the mass spectrometer.

• The sample is injected into the instrument.
•  It may be vaporized by heating. 
• The vaporized sample is then passed into an ionizing beam of electrons which knock electrons off the sample to create positive ions.
• These positive ions are then accelerated by some electrostatically charged plates into a magnetic field.
• The magnetic field then deflects the particles according to their mass/charge ratio.
• The deflected ions then arrive at the detector.

You can test yourself on the atomiser by clicking this link. It is a timed quiz.

OXIDATION AND REDUCTION

There are many definitions of oxidation.
1. It is the addition of oxygen to a substance.
2. It is the removal of hydrogen from a substance.
3. It is also the increase in the oxidation state of an element or molecule.
4. It can also be defined as the loss of electrons.

Examples of oxidation:

•  Oxygen-based cleaners use oxidation process for their actions.
• The sterilizing powers of hydrogen peroxide is based on oxidation. 
•  A rusty car is due to oxidation.
•  Browned fruit has oxidation to blame. 

There are many definitions of reduction.
1. It is the removal of oxygen from a substance.
2. It is the  addition of hydrogen to a substance.
3. It is also the decrease in the oxidation state of an element or molecule.
4. It can also be defined as the gain of electrons.

Most of the time, oxidation occurs in tandem with reduction. This is called redox reaction. It comes from oxidation-reduction.  One atom or compound steals electrons from another atom or compound.

Rusting is a classic example of a redox reaction. When rusting happens, oxygen steals electrons from iron. Oxygen is reduced while iron gets oxidized. The resulting compound is called iron oxide, or rust.