Why does water appear blue?

How does the plum-pudding model illustrate the atom’s structure?

Westkost [7]

Answer:

The plum-pudding model proposed that an atom is composed of negatively-charged particles floating within a sea of positive charges. This sea of positive charges served to counterbalance the negative charge on the electrons so that the atom remains neutral.

Explanation:

J.J. Thompson from experiments he conducted with the rays produced from a cathode tube to which a high voltage is applied across its two ends, discovered that these rays were negatively charged and had a mass much much smaller than the mass of any known atom. These negatively-charged rays were later called electrons. Since the atom was neutral in charge overall, J.J. Thompson then proposed the plum-pudding model.

The plum-pudding model proposed that an atom is composed of negatively-charged particles floating within a sea of positive charges. This sea of positive charges served to counterbalance the negative charge on the electrons so that the atom remains neutral. The name of this model was chosen because it resembled the English dessert, plum-pudding.

3 0

3 years ago

A 150 W electric heater operates for 12.0 min to heat an ideal gas in a cylinder. During this time, the gas expands from 3.00 L

Brut [27]

Answer: The change in internal energy of the gas is 108.835 kJ

Explanation:

To calculate the work done for reversible expansion process, we use the equation:

$W=P\Delta V=-P(V_2-V_1)$

where,

W = work done

P = pressure = 1.03 atm

$V_1$ = initial volume = 3.00 L

$V_2$ = final volume = 11.0 L

Putting values in above equation, we get:

$W=-(1.03)\times (11.0-3.00)=8.24L.atm=834.9J=0.835kJ$ (Conversion factor: 1 L. atm = 101.325 J)

Calculating the heat from power:

$Q=P\times t$

where,

Q = heat required

P = power = 150 W

t = time = 12 min = 720 s (Conversion factor: 1 min = 60 s)

Putting values in above equation:

$Q=150\times 720=108000J=108kJ$

The equation for first law of thermodynamics follows:

$Q=dU+W$

where,

Q = total amount of heat required = 108 kJ

dU = Change in internal energy = ?

W = work done = -0.835 kJ

Putting values in above equation, we get:

$108kJ=dU+(-0.835)\\\\dU=(108+0.835)=108.835kJ$

Hence, the change in internal energy of the gas is 108.835 kJ

7 0

4 years ago

Calculate the vapor pressure of water above a solution prepared by dissolving 28.5 g of glycerin (c3h8o3) in 135 g of water at 3

pshichka [43]

Data:

Solute: 28.5 g of glycerin (C3H8O3)
Solvent: 135 g of water at 343 k.
Vapor pressure of water at 343 k: 233.7 torr.

Quesiton: Vapor pressure of water

Solution:

Raoult's Law: The vapour pressure of a solution of a non-volatile solute is equal to the vapour pressure of the pure solvent at that temperature multiplied by its mole fraction.

Formula: p = Xsolvent * P pure solvent

X solvent = moles solvent / moles of solution

molar mass of H2O = 2*1.0g/mol + 16.0 g/mol = 18.0 g/mol

moles of solvent = 135 g of water / 18.0 g/mol = 7.50 mol

molar mass of C3H8O3 = 3*12.0 g/mol + 8*1 g/mol + 3*16g/mol = 92 g/mol

moles of solute = 28.5 g / 92.0 g/mol = 0.310 mol

moles of solution = moles of solute + moles of solvent = 7.50mol + 0.310mol = 7.810 mol

Xsolvent = 7.50mol / 7.81mol = 0.960

p = 233.7 torr * 0.960 = 224.4 torr

Answer: 224.4 torr

8 0

4 years ago

A sample of gas contains 0.1900 mol of CO(g) and 0.1900 mol of NO(g) and occupies a volume of 22.0 L. The following reaction tak

worty [1.4K]

Answer:

V₂ = 16.5 L

Explanation:

To solve this problem we use Avogadro's law, which applies when temperature and pressure remain constant:

V₁/n₁ = V₂/n₂

In this case, V₁ is 22.0 L, n₁ is [mol CO + mol NO], V₂ is our unknown, and n₂ is [mol CO₂ + mol N₂].

n₁ = mol CO + mol NO = 0.1900 + 0.1900 = 0.3800 mol

We use the reaction to calculate n₂:

2CO(g) + 2NO(g) → 2CO₂(g) + N₂(g)

mol CO₂:

0.1900 mol CO * $\frac{2molCO_{2}}{2molCO} =$ 0.1900 mol CO₂

mol N₂:

0.1900 mol NO * $\frac{1molN_{2}}{2molNO} =$ 0.095 mol N₂

n₂ = mol CO₂ + mol N₂ = 0.1900 + 0.095 = 0.2850 mol

Calculating V₂:

22.0 L / 0.3800 mol = V₂ / 0.2850 mol

V₂ = 16.5 L

3 0

4 years ago

Someone pls help me I will make you brain

harkovskaia [24]

Answer:

C

Explanation:

4 0

3 years ago

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