Free science quizzes and questions for exams - 10 Nov 2014

1. _____________ is the smallest unit of an element.
[A]An electron
[B]An atom
[C]A proton
[D]A neutron


2. The human stomach contains acid. Sodium bicarbonate (NaHCO3) is often found as a component of antacids, which are used to settle upset stomachs. It reacts in a similar way to normal carbonates, causing people to burp. Why does sodium bicarbonate make people burp?
[A]It settles on top of the stomach contents
[B]It produces hydrogen gas
[C]It produces carbondioxide gas
[D]It solidifies in the stomach


3. What does the word 'combustion' refer to?
[A]The burning of a compound in oxygen
[B]A reaction that involves heat and smoke
[C]The flames that result when something burns
[D]The reaction that involves hot acids and bases


4. Mobile phones use microwaves to send information to a transmitter What type of energy is used to carry the information from the mobile phone to a transmitter?
[A]Sound
[B]Heat
[C]Electromagnetic
[D]Light


5. What process add carbon dioxide to the atmosphere?
[A]Burning, decay and respiration
[B]Burning, decay and photosynthesis
[C]Respiration, decay and photosynthesis
[D]Burning, photosynthesis and respiration