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3 years ago

How does air above a heated surface move?

1 answer:

6 0

When air is warmed up, its molecules move faster and faster and as a result they move further from each other. They still have the same mass, but they now occupy a larger volume. This means that its density is smaller.
The opposite when air is cooled off. The molecules slow down, get closer together, occupy a smaller volume and therefore its density is bigger.

When air is warmed up, it goes up. Once it's up there, is cools off and goes back down. Near the heated surface the air gets warmed up again, goes up, cools down, goes back down, and again and again.
that is called convection cells

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How is 1 hectoliter different from 1 kiloliter?

LUCKY_DIMON [66]

1 hectoliter is 26.4172

1 kiloliter is 264.172

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3 years ago

Read 2 more answers

How is energy related to the change of state represented by the model?

andreev551 [17]

Answer:

Explanation:

the answer is C. Atoms lose energy as a gas changes to a solid. hope your 2020 goes well stay happy

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3 years ago

1. Identify the reactants in this chemical equation: 2H2 + O2 + 2H2O

USPshnik [31]

Oxygen and hydrogen

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3 years ago

What is the percent ionization of a 1.8 M HC2H3O2 solution (Ka = 1.8 10-5 ) at 25°C?

xz_007 [3.2K]

Answer:

B) 0.32 %

Explanation:

Given that:

$K_{a}=1.8\times 10^{-5}$

Concentration = 1.8 M

Considering the ICE table for the dissociation of acid as:-

$\begin{matrix}&CH_3COOH&\rightleftharpoons &CH_3COOH&+&H^+\\ At\ time, t = 0 &1.8&&0&&0\\At\ time, t=t_{eq}&-x&&+x&&+x\\ ----------------&-----&-&-----&-&-----\\Concentration\ at\ equilibrium:-&1.8-x&&x&&x\end{matrix}$

The expression for dissociation constant of acid is:

$K_{a}=\frac {\left [ H^{+} \right ]\left [ {CH_3COO}^- \right ]}{[CH_3COOH]}$

$1.8\times 10^{-5}=\frac{x^2}{1.8-x}$

$1.8\left(1.8-x\right)=100000x^2$

Solving for x, we get:

x = 0.00568 M

Percentage ionization = $\frac{0.00568}{1.8}\times 100=0.32 \%$

Option B is correct.

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3 years ago

Which of the following has the greatest electronegativity difference between the bonded atoms? View Available Hint(s) Which of t

Reptile [31]

Answer: A group 1 alkali metal bonded to fluoride, such as LiF.

Explanation:

Electronegativity is defined as the property of an element to attract a shared pair of electron towards itself. The size of an atom increases as we move down the group because a new shell is added and electron gets added up.

1. A strong acid made of hydrogen and a halogen, such as HCl : A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms. Electronegativity difference = electronegativity of chlorine - electronegativity of hydrogen = 3-2.1= 0.9

2. A group 1 alkali metal bonded to fluoride, such as LiF: Ionic bond is formed when there is complete transfer of electron from a highly electropositive metal to a highly electronegative non metal.

Electronegativity difference = electronegativity of fluorine - electronegativity of lithium= 4-1= 3

3. Carbon bonded to a group 6A (16) nonmetal chalcogen, such as in CO: A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.

Electronegativity difference = electronegativity of oxygen - electronegativity of carbon= 3.5-2.5= 1.0

4. A diatomic gas, such as nitrogen $(N_2)$ : Non-polar covalent bond is defined as the bond which is formed when there is no difference of electronegativities between the atoms.

Electronegativity difference = 0

Thus the greatest electronegativity difference between the bonded atoms is in LiF.

7 0

3 years ago