Answer:
Newton's First Law states that an object in motion will stay in motion, an object at rest will stay at rest, at a constant velocity, unless an unbalanced force acts upon it.
Newtons First law of motion has to do with seat belts because think about it, what happens when we don't wear a seat belt and our vehicle comes to a quick stop. What happens to you? You move forward and stay in motion until an unbalanced force acts upon you. Now what is an unbalanced force? An unbalanced force is one that is not opposed by an equal and opposite force operating directly against the force intended to cause a change in the object's state of motion or rest. So, when you come to a stop, you wouldn't stop motion unless a force is caused to change your motion and put you at rest. If you were wearing a seat belt, the seat belt would act as the unbalanced force, it would stop you from being in motion.
Answer:
B. 0.2.
Explanation:
<em>n = mass/molar mass</em>
mass of CaCO₃ = 20 g, molar mass of CaCO₃ = 100.0869 g/mol.
<em>∴ n = mass/molar mass = </em>(20 g)/(100.0869 g/mol) <em>= 0.1998 ≅ 0.2 mol.</em>
<em></em>
<em>So, the right choice is: B. 0.2.</em>
Answer : The final temperature of the copper is, ![87.29^oC](https://tex.z-dn.net/?f=87.29%5EoC)
Solution :
Formula used :
![Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})](https://tex.z-dn.net/?f=Q%3Dm%5Ctimes%20c%5Ctimes%20%5CDelta%20T%3Dm%5Ctimes%20c%5Ctimes%20%28T_%7Bfinal%7D-T_%7Binitial%7D%29)
where,
Q = heat gained = 299 cal
m = mass of copper = 52 g
c = specific heat of copper =
= final temperature = ?
= initial temperature = ![25^oC](https://tex.z-dn.net/?f=25%5EoC)
Now put all the given values in the above formula, we get the final temperature of copper.
![299cal=52g\times 0.0923cal/g^oC\times (T_{final}-25^oC)](https://tex.z-dn.net/?f=299cal%3D52g%5Ctimes%200.0923cal%2Fg%5EoC%5Ctimes%20%28T_%7Bfinal%7D-25%5EoC%29)
![T_{final}=87.29^oC](https://tex.z-dn.net/?f=T_%7Bfinal%7D%3D87.29%5EoC)
Therefore, the final temperature of the copper is, ![87.29^oC](https://tex.z-dn.net/?f=87.29%5EoC)
Answer: Compound
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: Copper ![Cu](https://tex.z-dn.net/?f=Cu)
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: water ![H_2O](https://tex.z-dn.net/?f=H_2O)
![2H_2O\rightarrow 2H_2+O_2](https://tex.z-dn.net/?f=2H_2O%5Crightarrow%202H_2%2BO_2)
Thus as it give that the red sample on being heated, a gas is released and a blue powder is left after the heating. Thus the given sample is a compound.