Answer: (3) silicon
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane 
, propanone 
and water 
Answer:
Explanation:
<h3><u>Given data:</u></h3>
Acceleration = a = 0.4 m/s²
Initial Speed = 
= 20 m/s
Final Speed = 
= 40 m/s
<h3><u>Required:</u></h3>
Time = t = ?
<h3><u>Formula:</u></h3>
<h3><u>Solution:</u></h3>
Rearranging formula for t
![\displaystyle t =\frac{V_f-V_i}{a} \\\\t = \frac{40-20}{0.4} \\\\t = \frac{20}{0.4} \\\\\boxed{t = 50 \ seconds}\\\\\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20t%20%3D%5Cfrac%7BV_f-V_i%7D%7Ba%7D%20%5C%5C%5C%5Ct%20%3D%20%5Cfrac%7B40-20%7D%7B0.4%7D%20%5C%5C%5C%5Ct%20%3D%20%5Cfrac%7B20%7D%7B0.4%7D%20%5C%5C%5C%5C%5Cboxed%7Bt%20%3D%2050%20%5C%20seconds%7D%5C%5C%5C%5C%5Crule%5B225%5D%7B225%7D%7B2%7D)
Ice melts when heat energy causes the molecules to move faster, breaking the hydrogen bonds between molecules to form liquid water.
It is two or more objects and different things that can be removed from each other.
Answer:
Petrochemicals are chemical products derived from petroleum, although many of the same chemical compounds are also obtained from other fossil fuels such as coal and natural gas or from renewable sources such as corn, sugar cane, and other types of biomass.
