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30 gram of a radioactive substance that has a half-life of 2 days after 2 days how much will be left?
With radioactive decay, predicting when any individual atom will decay is nearly impossible. However, when a lot a particles are present, then it is possible to get a general idea of how much will decay in a certain period of time. The half-life is this measurement, and it is the time that it takes for one halfof the substance to decay. Hence half-life or how long it takes for half to "die".
For any size sample of a substance, the half-life is how long it takes for half to be left, so for a substance with a half-life of 2 days, half of the substance will decay in two days. Therefore your answer is simply half of 30g which is 15g.
Additional reading: http://simple.wikipedia.org/wiki/Radioactive_decay
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How much of one gram of radium-226 will remain unchanged after four half-lives?
After each half-life, half of the radium-226 will decay. Therefore, after four half-lives, 1/2^4 or 1/16th of the original gram of radium-226 will remain unchanged. This means that 1/16th of a gram, or 0.0625 grams, will still be unchanged after four half-lives.
The energy required to melt one gram of a substance is known as what?
The energy required to melt one gram of a substance is known as the heat of fusion.
Is the volume per gram of a substance is a chemical extensive property?
If you mean gram/volume, which is density, it is an intensive property.
What is the quantity of heat in joules or calories required to raise the temperature of 1 gram of a substance 1C?
The quantity of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius is defined as the specific heat capacity of that substance. It is measured in joules per gram degree Celsius (J/g°C) or in calories per gram degree Celsius (cal/g°C).
How do you compare grams to ounces by volume?
You can't, because the gram isn't a volume. The volume of a gram depends on what substance you have a gram of. A gram of air has more volume than a gram of water, and a gram of stone, lead, or gold has a very, very tiny volume.
Radioactive iodine-131 has a half-life of eight days. The amount of a 200.0 gram sample left after 32 days would be -?
12.5 g
What is a gram of a molecular substance?
A gram of a molecular substance is the quantity that will have a mass of 1 gram.
The set of ordered pairs (t,m) where m is the remaining mass of a 500-gram sample of a radioactive substance that has been decaying for t hours?
Hvbh
How much of one gram of radium-226 will remain unchanged after four half-lives?
After each half-life, half of the radium-226 will decay. Therefore, after four half-lives, 1/2^4 or 1/16th of the original gram of radium-226 will remain unchanged. This means that 1/16th of a gram, or 0.0625 grams, will still be unchanged after four half-lives.
What is the half life of a radioactive isotope if it takes 6.2 days for a 72 gram sample to decay to 18grams?
18 grams are one fourth of the original sample mass of 72 grams. Accordingly, the half life is 6.2/4 = 1.55 days.
What is the heat required to change the temperature of 1 gram of a substance?
The heat required to change the temperature of 1 gram of a substance is known as the specific heat capacity of that substance. It is the amount of heat energy needed to raise the temperature of 1 gram of the substance by 1 degree Celsius.
Is the size of one gram as large as a us quarter?
A size of a gram of rice is different from a gram of gold or water or any other substance.
The energy required to melt one gram of a substance is known as what?
The energy required to melt one gram of a substance is known as the heat of fusion.
How much is one gram in size?
The size of one gram can vary depending on the density of the substance. For example, one gram of lead would be much smaller in size compared to one gram of cotton. Typically, one gram of a substance like sugar or salt would be about the size of a standard paperclip.
Substance with density of more than one gram?
oz.
Is the volume per gram of a substance is a chemical extensive property?
If you mean gram/volume, which is density, it is an intensive property.
What is the complete burning of 1 gram of a substance called?
The complete burning of 1 gram of a substance is called combustion. During combustion, the substance reacts with oxygen to produce heat, light, and often carbon dioxide and water as byproducts.
