A compound is a substance composed of 2 or more chemical elements.
The model does not represent a compound because it shows two atoms of the same element combined. To be a compound the model would need to contain atoms of different element, represented by different colored balls. Therefore, the picture does not represent a compound. :)
Answer:
<em>The correct option is B) two liquids are mixed at room temperature and a gas forms.</em>
Explanation:
A chemical change can be described as a change which results in the formation of a new substance by the reactants. In the option B, two liquids react to form a new product which is a gas. Hence, it is an example of chemical change.
Other options,like option D, is not a chemical change as by crushing a solid no new product is formed. Option C is also not correct because as when salt dissolves in water, no new product is made.
An extensive property is a property that deals with the amount of a substance. An extensive property of marker ink would be the volume of the ink in the pen.
An intensive property is a property about the type of substance you're looking at. So, an intensive property of marker ink would be the color of the ink.
To the eye – taken by itself – Alpha Centauri A appears as the fourth-brightest star seen from Earth, just slightly outshone by Arcturus. However, the combined light of Alpha Centauri A and B is slightly greater than Arcturus, so in that sense it appears as the third-brightest star visible in Earth's sky.
