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4 years ago

Describe two differences between Mendeleev's periodic table and the modern periodic table

1 answer:

6 0

There's a massive improvement in the layout, to begin with. Elements are frequently colour-coded to differentiate between their physical properties.

Mendeleev's periodic table has no place for isotopes, and also placed dissimilar atoms together in groups.

Mendeleev also left gaps for elements he suspected would be discovered, but he did not have the equipment to discover. These were later discovered through things like electrolysis. These days these unknown elements are not so evenly spread, but are mostly found around unununium.

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As a person squeezes and applies pressure to the outside of a balloon, air particles inside

mixas84 [53]

The air particle inside the balloon will collide more with each other and the temperature inside the balloon will increase.

As a person squeezed and applies the pressure to the outside of a balloon, the air particle inside the balloon gains energy and collide with each other, the particle of the air also try leave the balloon surface will implies equal pressure on the wall of the balloon, as the pressure outside the balloon increase, the inside pressure will also increase.

7 0

3 years ago

if a mass on a spring bobs up nad down completing 2 full cycles every section. WHat are the periouds and frequency of the mass

Alika [10]

Answer:

This question is incomplete

Explanation:

This question is incomplete because of the absence of the time taken to complete one full cycle.

Frequency (f) will be calculated first as

f = N ÷ t

where N is the number of cycles and t is the time taken to complete one full cycle. The unit for frequency is Hertz (Hz).

To calculate the period, T, the formula below will be used

T = 1 ÷ f

The unit for period is secs

4 0

3 years ago

The rare earth elements include

Alex73 [517]

Sc (21) , Y (39) , La (57) , Ce (58) , Pr (59) , Nd (60) , Pm (61) , Sm (62) , Eu (63) , Gd (64) , Tb (65) , etc (hoped that helped)

6 0

4 years ago

You would like to store 8.1 J of energy in the magnetic field of a solenoid. The solenoid has 620 circular turns of diameter 6.6

marta [7]

Answer:

(a) The current needed is 56.92 A

(b) The magnitude of the magnetic field inside the solenoid is 0.134 T

Explanation:

Given;

energy stored in the magnetic field of solenoid, E = 8.1 J

number of turns of the solenoid, N = 620 turns

diameter of the solenoid, D = 6.6 cm = 0.066 m

radius of the solenoid, r = D/2 = 0.033 m

length of the solenoid, L = 33 cm = 0.33 m

Inductance of the solenoid is given as;

$L= \frac{\mu_o N^2 A}{l}$

where;

A is the area of the solenoid = πr² = π (0.033)² = 0.00342 m²

μ₀ is permeability of free space = 4π x 10⁻⁷ H/m

$L= \frac{4\pi*10^{-7} *620^2 *0.00342}{0.33} \\\\L = 0.005 \ H$

(A). How much current needed

Energy stored in magnetic field of solenoid is given as;

$E = \frac{1}{2} LI^2\\\\$

Where;

I is the current in the solenoid

$E = \frac{1}{2} LI^2\\\\I^2 = \frac{2E}{L}\\\\I = \sqrt{\frac{2*8.1}{0.005}}\\\\ I = 56.92 \ A$

(B) The magnitude of the magnetic field inside the solenoid

B = μ₀nI

where;

n is number of turns per unit length

B = μ₀(N/L)I

B = (4π x 10⁻⁷)(620/0.33)(56.92)

B = 0.134 T

$U_B = \frac{B^2}{2\mu_0} \\\\U_B = \frac{(0.134)^2}{2*4\pi*10^{-7}} \\\\U_B = 7143.54 \ J/m^3\\\\U_B = 7.144 \ kJ/m^3$

3 0

3 years ago

Compute the order of magnitude of the mass of a bathtub half full of pennies. (Assume the pennies are made entirely of copper.)

devlian [24]

Answer:

Mass = 873.6kg = 0.874 × 10^3 kg

Order = 3

Question:

Compute the order of magnitude of the mass of a bathtub half full of pennies.(Assume the pennies are made entirely of copper and the tub measures 1.3 m by 0.5 m by 0.3 m)

Explanation:

Given:

Dimensions of the tub = 1.3 m by 0.5 m by 0.3 m

Density of copper d = 8960kg/m^3

Mass = volume × density

Volume of tub = L×B×H = 1.3 × 0.5 × 0.3 = 0.195m^3

Since the tub is half full:

V = 0.195/2 = 0.0975m^3

Mass = 8960kg/m^3 × 0.0975m^3

Mass = 873.6kg = 0.874 × 10^3 kg

Order = 3

Note: Order of magnitude is of the form:

N = a × 10^b

Where;

b = order of magnitude

and

1/√10 </= a < √10

8 0

4 years ago