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3 years ago

Why does the reactivity of the alkali metals decrease from cesium to lithium?

Chemistry

1 answer:

Olin [163]3 years ago

7 0

Explanation:

Alkali metals are more reactive since they are available in nature as combined state.

And from top to bottom reactivity increases due to increase in the size of metal and also forces of attraction between nucleus and valency electrons is more hence Valency electrons held less tigthly with nulceus .

Hence less energy(ionizationation)is need to removes electrons.

Hence lithium is least reactive and Cs is more reactive.

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The mass per unit volume is substance is called

gregori [183]

The mass per volume of a substance is called its density.

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4 years ago

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Which of the following statements describes a liquid?

goldfiish [28.3K]

Answer:

A liquid has a definite volume but not a definite shape

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3 years ago

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A person purchases a bag of potato chips that was sealed in San Francisco, CA where the elevation is 50 feet above sea level and

bogdanovich [222]

Hello, I Am BrotherEye

Answer:

As the atmospheric pressure decreases with increase in altitude, when a sealed bag of chips is taken to higher altitude then the pressure of the gases inside the bag become greater than the outer atmospheric pressure and apply pressure on the side covering of the chips bag due to which the chips bag expand.

Explanation:

Atmospheric pressure decreases with increasing altitude. Let's assume you tie up a bag at sea level altitude (with little air inside). That air inside the bag is at 1atm as long as you're at sea level.

Now you start going up, your altitude increases and atmospheric pressure decreases (remember what I said in the beginning about atmospheric pressure decreasing with increasing altitude?).

Let's say you reach an altitude where the atmospheric pressure is 0.5atm, the force acting inside the bag which is pushing it outward is now greater than the force acting on it which is pushing it inward (1atm>0.5atm). As a result, the air inside the bag will push the sides of the bag outward, thus inflating it to a point where the pressure inside the bag becomes 0.5atm or the bag stops stretching.

For the same reason, if you bring the same bag down and take it too deep into the earth (at an altitude lower than sea level) or if you inflate the bag at a very high altitude and bring it down to sea level, it will deflate.

Best Of Luck

BrotherEye

6 0

3 years ago

How does the number of Carbon atoms per molecule affect the state at room temperature? Explain how this is similar or different

RSB [31]

Explanation:

There are three states of matter:

1) Solid: In this state, the particles lie closer to each other. there is a strong intermolecular force of attraction between the particles.

2) Liquid: In this state, the particles are at a certain distance to each other. There is an intermediate intermolecular force of attraction between the particles.

3) Gas: In this state, the particles are farther from each other. There is weaker intermolecular force of attraction between the particles.

As the number of carbon atoms in a molecule increases, the number of particles increases and the particles will come closer to each other. Hence, the state of matter will shift towards the solid state.

Viscosity is defined as the tendency to resist the particles to flow. As, the number of carbon atoms increases, the Vander-Walls forces increases, the particles are closer to each other and Hence, the viscosity will increase.

7 0

3 years ago

Blast furnaces extra pure iron from the Iron(IIl)oxide in iron ore in a two step sequence. In the first step, carbon and oxygen

OLga [1]

Answer:

5.9 kg

Explanation:

We must work backwards from the second step to work out the mass of oxygen.

1. Second step

Mᵣ: 55.84

Fe₂O₃ + 3CO ⟶ 2Fe + 3CO₂

m/kg: 7.0

(a) Moles of Fe

$\text{Moles of FeO} = \text{7000 g Fe} \times \dfrac{\text{1 mol Fe}}{\text{55.84 g Fe}} = \text{125 mol Fe}$

(b) Moles of CO

$\text{Moles of CO} = \text{125 mol Fe} \times \dfrac{\text{3 mol CO}}{\text{2 mol Fe}} = \text{188 mol CO}$

However, this is the theoretical yield.

The actual yield is 72. %.

We need more CO and Fe₂O₃ to get the theoretical yield of Fe.

(c) Percent yield

$\begin{array}{rcl}\text{Percent yield} &=& \dfrac{\text{ actual yield}}{\text{ theoretical yield}} \times 100 \, \%\\\\ 72. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.72 &= &\dfrac{\text{188 mol}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{188 mol}}{0.72}\\& = & \textbf{261 mol}\\\\\end{array}$

We must use 261 mol of CO to get 7.0 kg of Fe.

2. First step

Mᵣ: 32.00

2C + O₂ ⟶ 2CO

n/mol: 261

(a) Moles of O₂

$\text{Moles of O}_{2} = \text{261 mol CO} \times \dfrac{\text{1 mol O}_{2}}{\text{2 mol CO}} = \text{131 mol O}_{2}$

(b) Mass of O₂

$\text{Mass of O}_{2}= \text{131 mol O }_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \text{4180 g O}_{2}$

However, this is the theoretical yield.

The actual yield is 71. %.

We need more C and O₂ to get the theoretical yield of CO.

(c) Percent yield

$\begin{array}{rcl}71. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.71 &= &\dfrac{\text{4180 g}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{4180 g}}{0.71}\\\\& = & \text{5900 g}\\& = & \textbf{5.9 kg}\\\end{array}$

We need 5.9 kg of O₂ to produce 7.0 kg of Fe.

6 0

4 years ago