Why do elements need to be heated to emit color?

A weather balloon is inflated to a volume of 29.1 L at a pressure of 733 mmHg and a temperature of 24.7 ∘C. The balloon rises in

goblinko [34]

Answer:

volume balloon 5.06 10⁻² m³

Explanation:

The balloon is inflated with air, which in the first instance behaves like an ideal gas, which has as an equation

PV = n R T

Where R is the ideal gas constant that is worth 8.314 J / mol K.

Let's use the initial data to calculate the number of moles of gas in the balloon that remains constant, but first we reduce all quantities to the SI system

V1 = 29.1 L (1 m2 / 1000 L) = 29.1 10⁻³ m³

P1 = 733 mmHg (1 105 Pa / 760 mmHg) = 0.964 10⁵ Pa

T1 = 24.7 + 273.15 = 297.85K

P2 = 365 mmHg (1 105 Pa / 760 mmHg) = 0.480 10⁵ Pa

T2 = -14.5 +273.15 = 258.65K

Let's clear and calculate the number of moles

n = P V / R T

n = P1 V1 / R T1

n = 0.964 10 5 29.1 10⁻³ / (8.314 297.85)

n = 1.13 moles

With the data of the second part we clear the volume and calculate

V = n R T / P

V2 = n R T2 / P2

V2 = 1.13 8.314 258.65 /0.480 10⁵

V2 = 5.062 10⁻² m³

5 0

3 years ago

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By means of a rope whose mass is negligible, two blocks are suspended over a pulley, as the drawing shows. The pulley can be tre

tankabanditka [31]

Answer:

Mass of the pull is 77 kg

Explanation:

Here we have for

Since the rope moves along with pulley, we have

For the first block we have

T₁ - m₁g = -m₁a = -m₁g/4

T₁ = 3/4(m₁g) = 323.4 N

Similarly, as the acceleration of the second block is the same as the first block but in opposite direction, we have

T₂ - m₂g = m₂a = m₂g/4

T₂ = 5/4(m₂g) = 134.75 N

T₂r - T₁r = I·∝ = 0.5·M·r²(-α/r)

∴ $M = -\frac{2}{a} (T_2-T_1)$

$M = -\frac{2}{2.45} (134.75-323.4) = 77 \, kg$

Mass of the pull = 77 kg.

5 0

3 years ago

Michaela is babysitting little Tommy Turner who is known to be terror . Michaela answered the phone when Tommy's parents called

Lina20 [59]

Answer: the ballon will explode.

Explanation:

The air in the ballon will increase its temperature and, according to the laws of behavior of the gases, it will expand until it explode.

You can assume ideal gas behavior and use PV = nRT, where you can see that the volume V and P are proportional to the temperature T, so with the increase in temperature the ballon will increase its volume, until the material of the ballon can not expand more, when the pressure will increase and the material will fail.

7 0

2 years ago

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The energy expenditure value of traveling by car is 3.6 mj/passenger-kilometer. The value for traveling by train is 1.1 mj/passe

andrezito [222]

Answer:

Using lighter material in car construction, improving energy efficiency by enhancing engine design or replacing the engine with more efficient technologies.

Explanation:

Using lighter materials in the car construction, reducing the potential energy required to accelerate and to move the car, as well as energy losses due to rolling friction. There is evidence of such benefits by replacing steel and aluminium parts with components made of composite materials.

Improving the design of internal combustion engines to minimize energy losses and accordingly, improving energy efficiency. A more radical approach is replacing internal combustion engines with electric engines, which offer higher efficiencies. Such conclusions can be easily inferred from model based on Work-Energy Theorem and Principle of Energy Conservation:

$\eta_{engine} \cdot U_{engine} = \frac{1}{2} \cdot m_{car} \cdot v^{2} + \mu_{r} \cdot m_{car} \cdot g \cdot \Delta s$

7 0

3 years ago

What type of bond results from the side‑on overlap of orbitals?

Serga [27]

Answer:

A pi bond

Explanation:

A pi bond is a type of covalent bond that results from the formation of a molecular orbital by the side-to-side overlap of atomic orbitals along a plane perpendicular to a line connecting the nuclei of the atoms.

4 0

2 years ago