Can someone help me please

Antimony I think but I am not sure

Here is the full question:

An atom of argon has a radius of 71 .pm and the average orbital speed of the electrons in it is about 3.9 × 10⁷ m/s. Calculate the least possible uncertainty in a measurement of the speed of an electron in an atom of argon. Write your answer as a percentage of the average speed, and round it to significant digits.

Answer:

Explanation:

From the above information:

The radius of an atom of argon = 71 .pm = 71 × 10⁻¹² m

The diameter of the atom of argon Δx =142 × 10⁻¹² m

According to Heisenberg's Uncertainty Principle,

[tex]\Delta x. \Delta p_x \geq \dfrac{h}{2}[/tex]

[tex]\Delta x. \Delta V \geq \dfrac{h}{4 \pi m_e}[/tex]

[tex]\Delta V \geq \dfrac{h}{4 \pi m_e \Delta_x}[/tex]

[tex]\Delta V \geq \dfrac{6.634 \times 10^{-34} \ J.s}{4 \pi \times 9.1 \times 10^{-3} \ kg \times 142 \times 10^{-12} \ m}[/tex]

[tex]\Delta V \geq \dfrac{6.634 \times 10^{-34} \ J.s}{1.62382641 \times 10^{-11} \ kg.m}[/tex]

[tex]\Delta V \geq 4.08 \times 10^5 \ m/s[/tex]

where; the average speed [tex]V_{avg}[/tex] = 3.9  10⁷ m/s

∴

The percentage of the average speed is expressed as a fraction of:

[tex]\% = \dfrac{4.08 \times 10^5}{3.9 \times 10^7}\times 100[/tex]

[tex]\% =1.0462[/tex]

[tex]V_{avg } = 1.046 \times 10^0[/tex]

[tex]\mathbf{V_{avg }\simeq 1.0 \%}[/tex]

Answer:

I NEED HELP TOO AND ALSO PLEASE DONT 1 STAR 5 STAR FOR THE MEMES

Explanation:

Answer:

cup 2

Explanation:

it has more water in there therefore its more diluted

Answer:

Average atomic mass  = 12.25

Explanation:

Percent abundance of Z-12 = 75%

percent abundance of Z-13 = 25%

Average atomic mass = ?

Solution:

Average atomic mass  = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

Average atomic mass  = (75×12)+(25×13) /100

Average atomic mass =  900 + 325 / 100

Average atomic mass  = 1225 / 100

Average atomic mass  = 12.25 amu.

Answer:

[tex]m_{CO_2}=24.38gCO_2\\m_{H_2O}=8.550gH_2O[/tex]

Explanation:

Hello.

In this case, since the combustion of C7H12 which is probably heptyne (molar mass = 96 g/mol) is:

[tex]C_7H_1_2+10O_2\rightarrow 7CO_2+6H_2O[/tex]

In which the products are carbon dioxide (molar mass = 17 g/mol) and water (18 g/mol) that are in a 7:1 and 6:1 mole ratio with the heptyne, respectively; thus, the yielded mass of both carbon dioxide and water is:

[tex]m_{CO_2}=7.600gC_7H_{12}*\frac{1molC_7H_{12}}{96gC_7H_{12}}*\frac{7molCO_2}{1molC_7H_{12}} *\frac{44gCO_2}{1molCO_2} \\m_{CO_2}=24.38gCO_2\\\\m_{H_2O}=7.600gC_7H_{12}*\frac{1molC_7H_{12}}{96gC_7H_{12}}*\frac{6molH_2O}{1molC_7H_{12}} *\frac{18gH_2O}{1molH_2O} \\m_{H_2O}=8.550gH_2O[/tex]

Best regards.

Answer:

biome or habitat, nectar, pollen, pollinate, propagation

Explanation:

Do any of these terms sound familiar?

Answer:

68 degrees fahrenheit or 293.15 degrees kelvin

Explanation:

Answer:

68°F

Explanation:

Answer:

thts the acidic presence

Explanation:

Answer:456

Explanation:

Answer:

stay the same

Explanation:

Answer:

The pH at 25°C of 0.33M solution is 5.36.

Explanation:

Let us calculate -:

[tex]NaC_6H_5CO_2$\rightarrow$ salt of weak acid + sodium benzoate[/tex]

pH of salt of weak acid and sodium benzoate is given by-

pH =[tex]7+\frac{1}{2}pk_a+\frac{1}{2}log (concentration of salt)[/tex]  

concentration of salt = 0.33M

[tex]pK_a=4.2[/tex]

[tex]pH = 7 +\frac{4.2}{2} +\frac{1}{2}log (0.33)[/tex]

[tex]pH=7 +\frac{4.2}{2} + \frac{(-0.4815)}{2}[/tex]

 pH   = 5.36

Hence , the answer is 5.36

The question is incomplete, the complete question is;

“Consider the unbalanced chemical equation. Al(s) + Cl2(g) ------> AlCl3(s) A student tries to balance the equation by changing the subscript 2 on Cl to a 3. Explain why this is not correct. What is the correct balanced equation?”

Answer:

2Al(s) + 3Cl2(g) ------> 2AlCl3(s)

Explanation:

If the student changes the subscript of Cl from 2 to 3, he/she has written a symbol for a molecule that does not exist. Halogens exist as diatomic and not triatomic gases.

The balanced equation is; 2Al(s) + 3Cl2(g) ------> 2AlCl3(s).

Notice that the basic principles of valency are not violated in any of the species in the equation above. Cl3 violates the octet rule but Cl2 obeys the octet rule.

Answer:

ΔH=9.2 KJ

Explanation:

2NO₂→N₂O₄  ΔH=-57 KJ/mol

N₂ + O₂→2NO ΔH=180.6 KJ/mol

2NO + O₂→2NO₂ ΔH= -114.4 (notice this was reversed and sign changed

_____________________________________________

N₂+2O₂→N₂O₄ ΔH= 9.2 KJ

By reversing the third equation, we can get the O₂ on the left side or the (reactant side) so that we can get a total of 2O₂ in the final equation on the bottom. Cross out 2NO₂ on the first equation on the reactant side and 2NO₂ in equation 2 on the product side. You also want to cross out 2NO in the third equation on both the reactant and product side. This leaves the same above the line as below the line.

Since you reverse equation 3, the change in enthalpy will change sign so you input -57, 180.6 and -114.4 to get 9.2 KJ

Hope that helps.

Answer:

[tex]E=3.5149kJ[/tex]

Explanation:

Hello.

In this case, for such combustion of hexane which release heat, we can compute that amount by taking into account that the reaction releases 4163.0 kJ of energy every 1 mole of hexane, it means that for 72.78 g, which in moles is:

[tex]n_{hexane}=72.78g*\frac{1mol}{86.20g}=0.8443mol[/tex]

Thus the energy released when 0.8443 moles of hexane are released turn out:

[tex]E=n_{hexane}\Delta _cH=0.8443mol*-4163.0\frac{kJ}{mol}*\frac{1000J}{1kJ} \\\\E=3.5149kJ[/tex]

Best regards!

Answer:

4.81 g / mol

Explanation:

Given :

Titanium has an HCP unit cell

Radius of titanium, R = 0.1445 nm

Unit cell volume, [tex]$V_c= 6R^2 C\sqrt3$[/tex]

But for Ti, c/a = 1.58

           So, c  = 1.58 a

And a = 2R or c = 3.16 R

[tex]$V_c = 6R^2 \times 3.16 R \times \sqrt3$[/tex]

[tex]$V_c=6 \times 3.16 \times \sqrt3 \times (1.445 \times 10^{-8})^3 $[/tex]

[tex]$V_c= 9.91 \times 10^{-23}\ cm^3 / unit \ cell $[/tex]

Density of Ti (theoretical), [tex]$\rho=\frac{n. A_{Ti}}{V_C.N_A} $[/tex]

For HCP, n = 6 atoms per unit cell and atomic mass = 47.87 g/mol

[tex]$\rho=\frac{6 \times 47.87}{9.91 \times 10^{-23} \times 6.023 \times 10^{23}} $[/tex]

  = 4.81 g/mol

This is the theoretical density of titanium.

The value given in literature is 4.51 g/mol

Answer:

Using the equation A(t) = 400e-.032t

a) replace t with 4 so A(4) = 400e((-.032)(4))

The hardest part about this is making sure to use order of operations. Be certain it works like this:

A(4) = 400e-.128

A(4) = 400(.8799)

A(4) = 351.9 grams

b) A(8) = 400e((-.032)(8)) = 309.7 grams

c) A(20) = 400e((-.032)(20)) = 210.9 grams

Note here that even after 20 years, not quite half of the original amount is gone. So, we can anticipate that in finding the half life, that our answer should be slightly greater than 20 years.

d) 200 = 400e(-.032t)

Divide both sides of the equation by 400.

.5 = e(-.032t)

Change this to logarithmic form.

Ln .5 = -.032t

-.6931≈ -.032t

t ≈ 21.7 years

Explanation:

Answer:

the answer is 105 g/mL

Explanation:

beacuse mass = density×volume

Answer:

They all produce a type of energy

Explanation:not sure but in wat i remenber that wat i learned in 5th grade

Explanation:

We know that,

Here,

Compound 2 has high melting point.

So,

Compound 2 is most likely to be an ionic compound.

Answer:

a

Explanation:

All of the complexes will be colored except [Zn(en)3]2.

Fe, Ni, Cr, and Cu all form colored complexes because of their partially-filled d-orbitals and are generally referred to as transition elements. The d-orbital can split into higher and lower orbitals and electrons can jump from one level to the other. The jumping of electrons leads to light absorption and this characteristic impacts color to elements with partially-filled d-orbitals.

Zinc does not possess a partially-filled d-orbital and as such, its electrons cannot transition between levels, even though it belongs to the 'd-block' element.

The correct option is a.

Answer:

Molar mass = 20.3 (Approx)

Explanation:

Given:

Density = 2.49 g/l

Pressure = 3 atm

Tempreture = 25 degree celcius = 273 + 25 = 298 k

Find:

Molar mass

Computation:

pm = drt

3(m) = (2.49)(298)(0.0821)

m = 20.3 (Approx)

Molar mass = 20.3 (Approx)

Answer:

DNA

Explanation:

Answer:

Explanation:

Dmitri Mendeleev was a Russian scientist that proposed the first periodic table of elements. Elements in his periodic table were arranged according to there relative atomic mass; however cobalt (Co) with an atomic mass of 58.93 was placed before nickel (Ni) with an atomic mass of 58.69 which was an anomaly as according to his law, nickel should come before cobalt since nickel has a lesser mass compared to cobalt.

Answer:

The energy increases the molecular motion and the kinetic energy of the substance.

Explanation:

A substance that absorbs energy will have their kinetic energy increased and also the molecular motion.

This is in compliance with the kinetic molecular theory of gases.

Answer:

A multicellular organism develops from a single cell (the zygote) into a collection of many different cell types, organized into tissues and organs. Development involves cell division, body axis formation, tissue and organ development, and cell differentiation (gaining a final cell type identity).

Explanation: