Answer:
The only liquid elements at standard temperature and pressure are bromine (Br) and mercury (Hg).
Answer:
Explanation:
A 40kg child throw stone of 0.5kg
At a direction of 5m/s
Recoil can be calculated using recoil of a gun formula
m_1•v_1 + m_2•v_2
m_1•v_1 = -m_2•v_2
The negative sign show that the momentum of the boy is directed oppositely to that of the stone
m_1 Is mass of boy
v_1 is the recoil velocity of the boy
m_2 is mass of stone
v_2 is the velocity of stone
Then,
m_1•v_1 = -m_2•v_2
40•v_1 = -0.5 × 5
40•v_1 = -2.5
v_1 = -2.5 / 40
v_1 = -0.0625 m/s
The recoil velocity of the boy is 0.0625 m/s
The Ideal Gas Law makes a few assumptions from the Kinetic-Molecular Theory. These assumptions make our work much easier but aren't true under all conditions. The assumptions are,
1) Particles of a gas have virtually no volume and are like single points.
2) Particles exhibit no attractions or repulsions between them.
3) Particles are in continuous, random motion.
4) Collisions between particles are elastic, meaning basically that when they collide, they don't lose any energy.
5) The average kinetic energy is the same for all gasses at a given temperature, regardless of the identity of the gas.
It's generally true that gasses are mostly empty space and their particles occupy very little volume. Gasses are usually far enough apart that they exhibit very little attractive or repulsive forces. When energetic, the gas particles are also in fairly continuous motion, and without other forces, the motion is basically random. Collisions absorb very little energy, and the average KE is pretty close.
Most of these assumptions are dependent on having gas particles very spread apart. When is that true? Think about the other gas laws to remember what properties are related to volume.
A gas with a low pressure and a high temperature will be spread out and therefore exhibit ideal properties.
So, in analyzing the four choices given, we look for low P and high T.
A is at absolute zero, which is pretty much impossible, and definitely does not describe a gas. We rule this out immediately.
B and D are at the same temperature (273 K, or 0 °C), but C is at 100 K, or -173 K. This is very cold, so we rule that out.
We move on to comparing the pressures of B and D. Remember, a low pressure means the particles are more spread out. B has P = 1 Pa, but D has 100 kPa. We need the same units to confirm. Based on our metric prefixes, we know that kPa is kilopascals, and is thus 1000 pascals. So, the pressure of D is five orders of magnitude greater! Thus, the answer is B.
The result of the Mexican victory was that fallen defenders
became heroes to the cause of Texan independence.<span> The Battle of
the Alamo took place between February 23 and March 6, 1836 and became the
central episode of the Texas
Revolution . After this thirteen-day battle, the
Mexican troops of General President Antonio
Lopez de Santa Anna began an attack on San Antonio de
Bexar, the current San Antonio in Texas. The Battle of the Alamo fought the
army of Mexico against
a group of Texan rebels, mostly American settlers. More than four thousand
men from Santa Ana stood in front of
the Alamo Fort , the last stronghold of the rebels, which
barely reached 187. The Alamo was not a fortress prepared to withstand a siege.
It is believed that all the rebels of the Alamo died in the siege, but Santa
Anna came to lose up to about 900 men during the days that lasted the fight. However,
the worst result for Santa Ana was precisely the resistance that the Texan
rebels had in the Alamo, which fostered the fighting spirit of the Texans. A
few days later, on March 14, 1836, Texas became independent from Mexico and a
month later, Santa Ana was imprisoned.</span>
