Explanation:
Half life is simply the amount of time it takes for half of a substance to decompose.
Options;
- Carbon-14 has a half-life of 5,730 years. A 30 gram sample will be 10 grams after 5,730 years. This is incorrect. After 5730 years, 15g of the sample ought to remain.
- Nickel-59 has a half-life of 76,000 years. A sample would go through 3 half-lives in 228,000 years. This is correct. 3 * 76000 = 228,000
- Hafnium-182 has a half-life of 9 million years. A 38 gram sample would be 4.75 grams in 27 million years. This is incorrect. Mass after 3 half lives (27/9) = 9.5 (38 / 2 / 2)
- Iron-60 has a half-life of 1.5 million years. In 6 million years a 40 gram sample would be reduced to 10 grams. This is incorrect. Mass after 4 half lives (6 / 1.5) = 2.5 gram (40 / 2 / 2 /2 / 2)
- Lead-202 has a half-life of 52,500 years. The original sample must have been 120 grams if you have a 60 gram sample after 105,000 years. This is incorrect. Original sampe = 240 gram. So after 2 half lives (105,000/52500), mass left = 60 (240 / 2 /2)
Answer:
4.78 %.
Explanation:
<em>mass percent is the ratio of the mass of the solute to the mass of the solution multiplied by 100.</em>
<em></em>
<em>mass % = (mass of solute/mass of solution) x 100.</em>
<em></em>
mass of MgSO₄ = 50.0 g,
mass of water = d.V = (0.997 g/mL)(1000.0 mL) = 997.0 g.
mass of the solution = mass of water + mass of MgSO₄ = 997.0 g + 50.0 g = 1047.0 g.
<em>∴ mass % = (mass of solute/mass of solution) x 100</em> = (50.0 g/1047.0 g) x 100 = <em>4.776 % ≅ 4.78 %.</em>
Answer:
Potential Energy:
- Hot water
- Ball at the top of a hill
- Battery
- Food
Kinetic Energy:
- Wave in the ocean
- Ball rolling down a hill
- Spinning motor
- Person running
Explanation:
Potential energy is the energy that is capable of generating work as a consequence of the position of a body.
The kinetic energy of a body is that energy that it possesses due to its movement.
Here we have to get the right answers which include the given phrase.
The correct answers are as following:
High boiling and melting points: Hydrogen bond increase the amount of energy required for phase changes to occur, thereby raising the boiling and melting points.
High specific heat: Hydrogen bond increase the amount of energy required for molecules to increase the speed, thereby raising the specific heat.
High surface tension: Hydrogen bonds produce strong inter molecular attractions, which increase surface tension.
The incorrect answer:
Lower density as a solid than as a liquid: actually, density of solid is more than density of liquid as hydrogen bonds in solid produce strong inter molecular attractions among molecules, which aggregates molecules together, hence volume of associated molecules reduces. Therefore, density of solid is more than that of liquid.
Answer: The new temperature is 10643 K
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,
where,
= initial pressure of gas = 750.0 mm Hg = 0.98 atm (760mmHg=1atm)
= final pressure of gas = 3.50 atm
= initial volume of gas = 2.00 L
= final volume of gas = 20.0 L
= initial temperature of gas = 
= final temperature of gas = ?
Now put all the given values in the above equation, we get:
Thus the new temperature is 10643 K
