Answer:
Forces acting on an object may be balanced or unbalanced. When the forces acting on an object have <u>equal</u> strength and act in opposite directions, they are <u>balanced</u>. These forces cancel out one another, and the <u>motion</u> of the object does not <u>change</u>. When the forces acting on an object are <u>unbalanced</u>, they do not cancel out one another. An unbalanced force acting on an object results in the object’s motion <u>changing</u>. The object may change its <u>speed</u> (speed up or slow
down), or it may change its <u>direction</u>. <u>Friction</u> is a force that resists the motion or the tendency toward motion between two objects in contact with each other. <u>Gravity</u> is a force that pulls objects toward one another. For example, Earth pulls all objects toward it.
Explanation:
Answer:
B and C
Explanation:
When we have to do a buffer solution we always have to choose the reaction that has the <u>pKa closer to the desired pH value</u>. When we find the pKa values we will obtain:
![pKa_1=-Log[6.9x10^-^3]=2.16](https://tex.z-dn.net/?f=pKa_1%3D-Log%5B6.9x10%5E-%5E3%5D%3D2.16)
![pKa_2=-Log[6.2x10^-^8]=7.20](https://tex.z-dn.net/?f=pKa_2%3D-Log%5B6.2x10%5E-%5E8%5D%3D7.20)
![pKa_3=-Log[4.8x10^-^13]=12.31](https://tex.z-dn.net/?f=pKa_3%3D-Log%5B4.8x10%5E-%5E13%5D%3D12.31)
The closer value is pKa2 with a value of 7.2. Therefore we have to use the second reaction. In which
is the <u>acid</u> and
is the <u>base</u>. Therefore the answer for the first question is B and the answer for the second question is C.
The Curiosity rover found sulfur compounds in rocks and carbon in organic compounds like propane, butene, benzene, toluene and thiophene.
It detected methane, not in soil samples, but in the Martian atmosphere.
It did not discover helium in underground pockets. The hole it can drill is only 5 cm deep.