Ask question

Ask question

All categories

7 days ago

8

A generic element, Z, has two isotopes, 45Z and 47Z, and an average atomic mass of 45.36 amu. The natural abundances of the two

isotopes are 80% 45Z and 20% 47Z. The isotopic mass of 45Z is 44.96 amu. What is the isotopic mass of 47Z?

1 answer:

lorasvet [2.4K]7 days ago

5 0

The isotopic mass of 47Z is calculated to be 46.96 amu. Isotopes of a single element differ in neutron count, and to ascertain the relative atomic mass, we consider each isotope's mass weighted by their natural abundance. This provided a computation to derive the mass of 47Z.

You might be interested in

Approximately 220 million tires are discarded in the U.S. each year. These tires present a disposal problem because they take up

lions [2629]

Answer:

A total of 2667 tires are required to satisfy the annual power needs of ten homes.

Explanation:

According to the Second Law of Thermodynamics, not all energy produced when tires are incinerated can be effectively used due to losses associated with finite temperature differences. The energy obtainable from a tire when burned, measured in kilowatt-hours ( $E_{out}$ ), can be calculated using the efficiency definition:

$E_{out} = \eta \cdot E_{in}$

Where:

$\eta$ - Efficiency, which is dimensionless.

$E_{in}$ - Energy released from burning, measured in kilowatt-hours.

Taking into account $\eta = 0.5$ and $E_{in} = 75\,kWh$ , the yearly energy yield from a tire amounts to:

$E_{out} = 0.5\cdot (75\,kWh)$

$E_{out} = 37.5\,kWh$

Thus, the number of tires necessary to meet the electricity demand of ten homes for one year is:

$n = \frac{(10\,homes)\cdot \left(10000\,\frac{kWh}{home} \right)}{37.5\,\frac{kWh}{tire} }$

$n = 2666.667\,tires$

A total of 2667 tires are necessary to satisfy the annual power needs of ten homes.

8 0

27 days ago

A compound that is composed of carbon, hydrogen, and oxygen contains 70.6% C, 5.9% H, and 23.5% O by mass. The molecular weight

Tems11 [2379]

Answer: The molecular formula will be $C_8H_8O_2$

Explanation:

When percentages are provided, we assume the total mass to be 100 grams.

Thus, the mass of each element corresponds to the specified percentage.

Mass of C= 70.6 g

Mass of H = 5.9 g

Mass of O = 23.5 g

Step 1: convert given masses to moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{70.6g}{12g/mole}=5.9moles$

Moles of H = $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{5.9g}{1g/mole}=5.9moles$

Moles of O = $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{23.5g}{16g/mole}=1.5moles$

Step 2: For determining the mole ratio, divide each molar amount by the smallest number of moles calculated.

For C = $\frac{5.9}{1.5}=4$

For H = $\frac{5.9}{1.5}=4$

For O = $\frac{1.5}{1.5}=1$

The resulting ratio of C: H: O= 4: 4: 1

Hence, the empirical formula obtained is $C_4H_4O$

The empirical weight is calculated as $C_4H_4O$ = 4(12)+4(1)+1(16)= 68g.

The molecular weight = 136 g/mole

Now the molecular formula needs to be obtained.

$n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{136}{68}=2$

The molecular formula can be derived as= $2\times C_4H_4O=C_8H_8O_2$

4 0

16 days ago

When 1.34 g Zn(s) reacts with 60.0 mL of 0.750 M HCl(aq), 3.14 kJ of heat are produced. Determine the enthalpy change per mole o

Alekssandra [2685]

Answer: The change in enthalpy for each mole of zinc involved in the reaction is 152.4 kJ/mol.

Explanation:

First, we need to determine the moles of Zn and HCl.

$\text{Moles of }Zn=\frac{\text{Mass of }Zn}{\text{Molar mass of }Zn}$

The molar mass of Zn is 65 g/mole

$\text{Moles of }Zn=\frac{1.34g}{65g/mole}=0.0206mole$

and,

$\text{Moles of }HCl=\text{Concentration of }HCl\times \text{Volume of solution}=0.750M\times 0.0600=0.0450mole$

Next, we must identify the limiting reagent and the excess reagent.

The chemical reaction given is:

$Zn(s)+2HCl(aq)\rightarrow ZnCl_2(aq)+H_2(g)$

According to the balanced reaction we find that

1 mole of $Zn$ reacts with 2 moles of $HCl$

Thus, 0.0206 moles of $Zn$ react with $0.0206\times 2=0.0412$ moles of $HCl$

This leads us to determine that $HCl$ is the excess reagent because the moles provided exceed the required moles, while $Zn$ is limiting and restricts product formation.

Now to find the enthalpy change for each mole of zinc reacting in this reaction.

From the reaction we gather that,[ [TAG_59]]

0.0206 moles of Zn yield heat = 3.14 kJ

This implies that 1 mole of Zn generates heat = $\frac{3.14kJ}{0.0206mol}=152.4kJ/mol$

Hence, the enthalpy change per mole of zinc involved in this reaction amounts to 152.4 kJ/mol.

5 0

16 days ago

At 400K both compounds are gases. At this temperature, which compound, CH4(g) or CCl4(g) , behaves more like an ideal gas

Alekssandra [2685]

Answer:

CH4

Explanation:

The ideal behavior of gases generally depends on the strength of intermolecular forces between gas molecules and whether polar bonds are present.

In the case of CCl4, polar bonds exist along with the more electronegative chlorine atom, leading to stronger intermolecular forces at 400K, as opposed to CH4 which contains only non-polar bonds.

Thus, at 400K, CH4 behaves more like an ideal gas compared to CCl4.

6 0

26 days ago

Two different atoms have six protons each and the same mass. However, one has a negative charge while the other has a positive c

castortr0y [2700]

The equal mass indicates that both atoms have the same number of protons and neutrons.

A positive charge signifies a difference in electron count.

Assuming the atomic number is A,

the mass number equals M.

In a neutral atom, there are A electrons.

A negatively charged atom would have A + 1 electrons [while the count of protons and mass number remains unchanged].

A positively charged atom contains A - 1 electrons [with consistent protons and mass number].

For instance: Cl- and Cl+.

8 0

1 month ago

Read 2 more answers