2. According to Newton's second law of motion, in which of these situations is the object

Barium-131 is used in the detection of bone tumors. The half-life of barium-131 is approximately 12 days. How long will it take

Evgesh-ka [11]

Barium-131's radiation level won't reach 1/4 of its initial level for 24 hours.

ln[A] t = -kt + ln[A] 0 is the integrated rate rule for the first-order reaction A's products.

A straight line is produced when the natural log of [A] is plotted as a function of time since this equation has the form y = mx + b.

How is the length of a half-life determined?

The amount of time needed for the reactant concentration to drop to half its initial value is known as the half-life of a reaction. A first-order reaction's half-life is a constant that is correlated with its rate constant:

t 1/2 = 0.693/k.

To know more about rate constant, visit:

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5 0

1 year ago

A student reacts 5.0 g of sodium with 10.0 g of chlorine and collect 5.24 g of sodium chloride. What is the percent yield of thi

Ede4ka [16]

Answer: The percent yield of this combination reaction is 41.3 %

Explanation : Given,

Mass of $Na$ = 5.0 g

Mass of $Cl_2$ = 10.0 g

Molar mass of $Na$ = 23 g/mol

Molar mass of $Cl_2$ = 71 g/mol

First we have to calculate the moles of $Na$ and $Cl_2$ .

$\text{Moles of }Na=\frac{\text{Given mass }Na}{\text{Molar mass }Na}$

$\text{Moles of }Na=\frac{5.0g}{23g/mol}=0.217mol$

and,

$\text{Moles of }Cl_2=\frac{\text{Given mass }Cl_2}{\text{Molar mass }Cl_2}$

$\text{Moles of }Cl_2=\frac{10.0g}{71g/mol}=0.141mol$

Now we have to calculate the limiting and excess reagent.

The balanced chemical equation will be:

$2Na+Cl_2\rightarrow 2NaCl$

From the balanced reaction we conclude that

As, 2 mole of $Na$ react with 1 mole of $Cl_2$

So, 0.217 moles of $Na$ react with $\frac{0.217}{2}=0.108$ moles of $Cl_2$

From this we conclude that, $Cl_2$ is an excess reagent because the given moles are greater than the required moles and $Na$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $NaCl$

From the reaction, we conclude that

As, 2 mole of $Na$ react to give 2 mole of $NaCl$

So, 0.217 mole of $HCl$ react to give 0.217 mole of $NaCl$

Now we have to calculate the mass of $NaCl$

$\text{ Mass of }NaCl=\text{ Moles of }NaCl\times \text{ Molar mass of }NaCl$

Molar mass of $NaCl$ = 58.5 g/mole

$\text{ Mass of }NaCl=(0.217moles)\times (58.5g/mole)=12.7g$

Now we have to calculate the percent yield of this reaction.

Percent yield = $\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100$

Actual yield = 5.24 g

Theoretical yield = 12.7 g

Percent yield = $\frac{5.24g}{12.7g}\times 100$

Percent yield = 41.3 %

Therefore, the percent yield of this combination reaction is 41.3 %

4 0

4 years ago

Sheela wants to make a computer model of a land ecosystem. Part of her model simulates the chemical processes of photosynthesis

shusha [124]

<span>The correct answer is A, the ligt-dependent reactions. These reactions are responsible for the production of glucose molecules, by the utilization of carbon dioxide, and water along with the sunlight. Glucose is then broken down during resiration process, for the production of ATP in mitochondria.</span><span />

5 0

3 years ago

Read 2 more answers

If an atom has a mass number of 23, which of the following is always true?

lesantik [10]

Atomic number is less than 11

8 0

3 years ago

2. What does the text list and describe?

Mariana [72]

Answer:

C. ways radiation is transferred into and through Earth's atmosphere