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3 years ago

What is a half-life of an isotope? please help

Chemistry

1 answer:

N76 [4]3 years ago

3 0

Answer:

Explanation:

Hello! Hope this helps!

One important measure of the rate at which a radioactive substance decays is called half-life, or t1/2. Half-life is the amount of time needed for one half of a given quantity of a substance to decay. Half-lives as short as 10–6 second and as long as 109 years are common.

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12. A beginner's bowling ball has a mass of 4.9 kg and a volume of 5.4 liters. Will it float in water,

Greeley [361]

Taking into account the definition of density and Archimedes' principle, the beginner bowling ball will float on the water.

But first it is neccesary to know that density is a quantity referred to the amount of mass in a certain volume of a substance or a solid object.

In other words, the density is the relationship between the weight (mass) of a substance and the volume that the same substance occupies.

The expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:

$density=\frac{mass}{volume}$

In this case, a beginner's bowling ball has a mass of 4.9 kg and a volume of 5.4 liters. This is:

mass= 4.9 kg= 4900 g (being 1 kg= 1000 kg)
volume= 5.4 L= 5400 mL (being 1L=1000 mL)

Replacing in the definition of density:

$density=\frac{4900 g}{5400 mL}$

Solving:

density=0.907 $\frac{g}{mL}$

On the other hand, Archimedes' principle says that an object immersed in a liquid experiences an upward vertical force equal to the weight of the volume of the dislodged liquid.

The sinking or floating of an object is determined by its density with respect to that of the liquid in which it is submerged.

Considering water as the liquid where the object is submerged in this case, an object with a higher density than water will sink. In contrast, an object with a lower density than water will float.

In this case, considering that water has a density of 1 $\frac{g}{mL}$ , the bowling ball for beginners has a lower density. This indicates that, having a lower density than water, the object will float.

In summary, the beginner bowling ball will float on the water.

Learn more about density:

5 0

3 years ago

Sugar has a lower melting point than salt because sugar is made of _________.

il63 [147K]

The correct answer is Crystals.

Unlike sugar, salt is not made out of crystals, but both salt and sugar are made out of atoms, that is molecules, and can have ions.

4 0

3 years ago

Which of the halide ions (f−, cl−, br−, and i−) is the most stable base? which is the least stable base?

Nezavi [6.7K]

You should take note that the question is about stability. A compound is stable if it does not easily react with other elements. Hence, its reactivity must be low. As you move down the group, reactivity decreases. So, the halide at the very bottom is the least reactive. It would then be logical that the most stable conjugate base is I⁻ and the least stable conjugate base is the most reactive which is F⁻.

3 0

3 years ago

Read 2 more answers

How many moles of H2O are needed to produce 5.6 mol of NaOH? Na2O + H2O --> 2NaOH

navik [9.2K]

Answer: 2.8 moles

Explanation:

The balanced equation below shows that 1 mole of sodium oxide reacts with 1 mole of water to form 2 moles of sodium hydroxide respectively.

Na2O + H2O --> 2NaOH

1 mole of H2O = 2 moles of NaOH

Let Z moles of H2O = 5.6 mole of NaOH

To get the value of Z, cross multiply

5.6 moles x 1 mole= Z x 2 moles

5.6 = 2Z

Divide both sides by 2

5.6/2 = 2Z/2

2.8 = Z

Thus, 2.8moles of H2O are needed to produce 5.6 mol of NaOH

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3 years ago

If a substance has a temperature of 273 kelvins, what is its temperature in degrees celsius?

kipiarov [429]

It is at 0 degrees Celsius

5 0

3 years ago