Answer:
D) burning a candle
A demonstration that contains both physical and chemical changes will be BURNING OF A CANDLE.
<em>This is because when a candle is lighted up, on the top of it (where we see flame) the oxygen and other gases present around will be chemically changed (burned up)</em>
<em>When the wax in the top of the candle will get melted due to the heat of the fire a physical change takes places.</em>
Answer:
11) E
12) C
13) M
14) C
15) M
16) M
17) C
18) E
19) C
20) M
Explanation:
An element is a pure substance such as gold and silver. You can find those elements in the periodic table. A compound is a substance consisted of molecules from two or more different elements. Water is made up of hydrogen and oxygen (H2O). Sugar is a very wide category of compounds. Carbon dioxide is made up of carbon and oxygen (CO2). Ice is frozen water/water in the solid state (H2O). A mixture is a group of substances held together physically. Seawater is a mixture of water and salt. A chocolate sundae is a mixture of chocolate sauce and ice cream. Air is a mixture of many gases including oxygen and nitrogen. A big mac is a mixture of burger meat, lettuce, tomatoes, etc.
Answer:
0.67 cm³
Explanation:
We can solve this problem by using the <em>definition of density</em>:
We can rearrange the equation and isolate volume:
As we are given both <em>the mass and the density</em>, we can now<u> calculate the volume</u>:
- Volume = 13 g ÷ 19.3 g/cm³
0.06 has one significant figure (unless there are zeros written after it). So I would round the result to 6000. Some teachers prefer at least 2 significant figures though.
Answer:
D. All of the above
Explanation:
We can place a piece of glass tubing into rubber stopper after the tubing has been fire polished and cooled by
Lubricating the tubing with water or glycerin.
Using a towel or cotton gloves for protection.
or by
Twisting the tubing and stopper carefully.
Hence we can say that all the above methods are equally useful for the above procedure.