What do you get when you mix lemons with gun powder

A 0.4272 g sample of an element contains 2.241 x 10 ^21 atoms . what is the symbol of the element?

grin007 [14]

Answer:

Likely $\rm In$ (indium.)

Explanation:

Number of atoms: $N = 2.241 \times 10^{21}$ .

Dividing, $N$ , the number of atoms by the Avogadro constant, $N_A \approx 6.023 \times 10^{23} \; \rm mol^{-1}$ , would give the number of moles of atoms in this sample:

$\begin{aligned} n &= \frac{N}{N_{A}} \\ &\approx \frac{2.241 \times 10^{21}}{6.023 \times 10^{23}\; \rm mol^{-1}} \approx 3.72 \times 10^{-3}\; \rm mol \end{aligned}$ .

The mass of that many atom is $m = 0.4272\; \rm g$ . Estimate the average mass of one mole of atoms in this sample:

$\begin{aligned}M &= \frac{m}{n} \\ &\approx \frac{0.4272\; \rm g}{3.72 \times 10^{-3}\; \rm mol} \approx 114.82\; \rm g \cdot mol^{-1}\end{aligned}$ .

The average mass of one mole of atoms of an element ( $114.82\; \rm g \cdot mol^{-1}$ in this example) is numerically equal to the average atomic mass of that element. Refer to a modern periodic table and look for the element with average atomic mass $114.82$ . Indium, $\rm In$ , is the closest match.

5 0

3 years ago

Given the partial equation: NO3− Pb2 → NO2 Pb4 , balance the reaction in acidic solution using the half-reaction method and fill

Fed [463]

Answer : The balanced reaction in acidic solution is,

$2NO_3^-+1Pb^{2+}+4H^+\rightarrow 2NO_2+1Pb^{4+}+2H_2O$

Explanation :

The given partial equation is,

$NO_3^-+Pb^{2+}\rightarrow NO_2+Pb^{4+}$

First we have to separate into half reaction. The two half reactions are:

$NO_3^-\rightarrow NO_2$

$Pb^{2+}\rightarrow Pb^{4+}$

Now we have to balance the half reactions in acidic medium, we get:

$NO_3^-+2H^++1e^-\rightarrow NO_2+H_2O$ ............(1)

$Pb^{2+}\rightarrow Pb^{4+}+2e^-$ ............(2)

Now we have to balance the electrons of the half reactions. When we are multiplying the equation (1) by 2, we get

$2NO_3^-+4H^++2e^-\rightarrow 2NO_2+2H_2O$ ...........(3)

Now we have to add both the half reactions (2) and (3), we get the final balanced chemical reaction.

$2NO_3^-+1Pb^{2+}+4H^+\rightarrow 2NO_2+1Pb^{4+}+2H_2O$

3 0

3 years ago

When a compound is dissolved in hot ethanol during a recrystallization, what is changing on a molecular level? The intermolecula

Feliz [49]

Answer:

The intermolecular forces between the solute and solvent.

Explanation:

When you are heating a solvent, the intermolecular forces are reduced because the distances between molecules are large. Thus, in a solution where solvent is hot the intermolecular forces between solute and solvent are lower than those solutions where solvent is in room temperature.

The covalent bonds do not change because this mean a chemical reaction that doesn't occur in a solution.

Usually solid solutes melts in a higher temperature than boiling point in solvents. Thus, a compound normally doesn't melt in a hot solvent.

I hope it helps!

3 0

2 years ago

Water exhibits a type of magnetism called ___________________ whereby in the presence of a strong magnetic field, the normally n

Lilit [14]

The answer is diamagnetism. It is a significant mechanical effect that happens in all materials; when it is the only influence to the magnetism, the material is named diamagnetic. Quartz and water are samples of diamagnetic materials. The diamagnetic influence is usually unimportant in materials holding strong lasting magnetic moments.

5 0

3 years ago

Que es un atomo y una molecula?

Setler79 [48]

Answer:

Atom - un átomo de hidrógeno pierde un electrón, adquiere una carga positiva

Molecule - Al aumentar el calor, las moléculas se alejan en mayor medida unas de otras y se intensifica su estado de agitación.

4 0

3 years ago