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3 years ago

10

How did Mendeleev arrange the elements in the first periodic table? In order of increasing atomic mass. In order of decreasing a

tomic mass. In order of increasing melting points and densities. In order of increasing atomic number.

1 answer:

hammer [34]3 years ago

7 0

Answer:

Mendeleev arranged the elements on the first periodic table by Increasing atomic mass

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A piece of mental with a mass of 106 g is placed in a 50 mL graduated cylinder.The volume rises from 20 mL to 31 mL. What is the

garik1379 [7]

Answer:

9.64g/mL

Explanation:

Given parameters:

Mass of the metal = 106g

Volume of cylinder = 50mL

Volume difference = 31mL - 20mL = 11mL

Unknown:

Density of the metal = ?

Solution:

To find the density of the metal, we use;

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

Density = $\frac{106}{11}$ = 9.64g/mL

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2 years ago

A rectangular corral of widths Lx = L and Ly = 2L contains seven electrons. What is the energy of (a) the first excited state, (

DiKsa [7]

Answer:

See explaination

Explanation:

The invariant mass of an electron is approximately9. 109×10−31 kilograms, or5. 489×10−4 atomic mass units. On the basis of Einstein's principle of mass–energy equivalence, this mass corresponds to a rest energy of 0.511 MeV.

Check attachment for further solution to the exercise.

3 0

3 years ago

Hexane and octane are mixed to form a 45 mol% hexane solution at 25 deg C. The densities of hexane and octane are 0.655 g/cm3 an

avanturin [10]

Answer:

The required volume of hexane is 0.66245 Liters.

Explanation:

Volume of octane = v=1.0 L= $1000 cm^3$

Density of octane= d = $0.703 g/cm^3$

Mass of octane ,m= $d\times v=0.703 g/cm^3\times 1000 cm^3=703 g$

Moles of octane = $\frac{m}{114 g/mol}=\frac{703 g}{114 g/mol}=6.166 mol$

Mole percentage of Hexane = 45%

Mole percentage of octane = 100% - 45% = 55%

$55\%=\frac{6.166 mol}{\text{Total moles}}\times 100$

Total moles = 11.212 mol

Moles of hexane :

$45%=\frac{\text{moles of hexane }}{\text{Total moles}}\times 100$

Moles of hexane = 5.0454 mol

Mass of 5.0454 moles of hexane,M = 5.0454 mol × 86 g/mol=433.9044 g

Density of the hexane,D = $0.655 g/cm^3$

Volume of hexane = V

$V=\frac{M}{D}=\frac{433.9044 g}{0.655 g/cm^3}=662.4494 cm^3\approx 0.66245 L$

(1 cm^3= 0.001 L)

The required volume of hexane is 0.66245 Liters.

5 0

3 years ago

mihalych1998 [28]

Explanation:

1. Cross-pollination between true-breeding plant with green pods and true-breeding plant with yellow pods.

2.The yellow pods do not appear because the heterozygous dominant for the green pods. So the green is dominant while the yellow is recessive. So the green is what comes out has the result..

8 0

3 years ago

A container is filled with Neon gas. It has a volume of 1.5L and a pressure of 101.3 kPa. If the volume of the container is incr

Marta_Voda [28]

Answer:

37.98 kPa.

Explanation:

We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

If n and T are constant, and have different values of P and V:

<em>(P₁V₁) = (P₂V₂)</em>

<em></em>

Knowing that:

P₁ = 101.3 kPa, V₁ = 1.5 L,

P₂ = ??? kPa, V₂ = 4.0 L.

Applying in the above equation

<em>(P₁V₁) = (P₂V₂)</em>

<em></em>

<em>∴ P₂ = (P₁V₁)/V₂</em> = (101.3 kPa)(1.5 L)/(4.0 L) = <em>37.98 kPa.</em>

7 0

3 years ago