Answer:
It is a chemical change.
Explanation:
When the electricity is off, the filament cools down to its original physical state. This physical process repeats every time the light is turned on and off. However, if the bulb is cracked and air is introduced, the oxygen in the air reacts with the tungsten filament which then undergoes a chemical change.
Answer:
F
Explanation:
A carousel can be made to rotate using different sources of energy. One may decide to use electric energy, manual effort, water energy or heat energy as in a candle carousel.
When the candle is lit, heat energy is supplied and warm air rises heating up the air near the carousel eventually causing it to start rotating.
Hence heat from the candle leads to a current of warm air that rises up, causing the carousel to start rotating.
Answer:
a -4
b - 8
c - 5
d 2
Explanation:
Significant Figures: The number of digits used to express a measured or calculated quantity. By using significant figures, we can show how precise a number is. ... Accuracy: Refers to how closely individual measurements agree with the correct or true value.
Answer:
NH2.
Explanation:
The mass of hydrogen in the sample = 1.525 - 1.333 = 0.192g.
Dividing the 2 masses by the relative atomic mass of hydrogen and nitrogen:
H: 0.192 / 1.008 = 0.1905
N: 1.333 / 14.007 = 0.09517
The ratio of N to H = 0.09517 : 0.1905
= 1 : 2.
So the empirical formula is NH2.
Elements in a group or a column have the same number of outer electrons so they have similar chemical properties
