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3 years ago

Provide at least three reasons why friction is needed.

2 answers:

6 0

Friction occurs when two surfaces come into contact. Excess friction hinders movement, and it wastes energy. Friction refers to a force that opposes motion. It is important because it is applied in almost all life processes.

levacccp [35]3 years ago

4 0

Friction slides or rolls one object to another

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A plastic bottle is closed outdoors on a cold day when the temperature is −15.0°C and is later brought inside where the temperat

Lana71 [14]

Answer:

Pressure = 1.14 atm

Explanation:

Hello,

This question requires us to calculate the final pressure of the bottle after thermal equilibrium.

This is a direct application of pressure law which states that in a fixed mass of gas, the pressure of a given gas is directly proportional to its temperature, provided that volume remains constant.

Mathematically, what this implies is

P = kT k = P / T

P1 / T1 = P2 / T2 = P3 / T3 =........= Pn / Tn

P1 / T1 = P2 / T2

P1 = 1.0atm

T1 = -15°C = (-15 + 273.15)K = 258.15K

P2 = ?

T2 = 21.5°C = (21.5 + 273.15)K = 294.65K

P1 / T1 = P2 / T2

P2 = (P1 × T2) / T1

P2 = (1.0 × 294.65) / 258.15

P2 = 1.14atm

The pressure of the gas after attaining equilibrium is 1.14atm

3 0

3 years ago

KMnO4 Assign oxidation numbers to each element in this compound.

zysi [14]

K=+1

Mn= +7

O= -2

That’s it!!!

8 0

3 years ago

Vitamin C contains the elements C, H, and O. It is known to contain 40.9% C and 4.58% H by mass. The molar mass of vitamin C has

soldier1979 [14.2K]

Answer:

C₆H₈O₆

Explanation:

First off, the percent of oxygen by mass of vitamin C is:

100 - (40.9+4.58) = 54.52 %

Assume we have one mol of vitamin C. Then we would have 180 grams, of which:

180 * 40.9/100 = 73.62 grams are of Carbon

180 * 4.58/100 = 8.224 grams are of Hydrogen

180 * 54.52/100 = 98.136 grams are of Oxygen

Now we convert each of those masses to moles, using the elements' respective atomic mass:

C ⇒ 73.62 g ÷ 12 g/mol = 6.135 mol C ≅ 6 mol C

H ⇒ 8.224 g ÷ 1 g/mol = 8.224 mol H ≅ 8 mol H

O ⇒ 98.136 g ÷ 16 g/mol = 6.134 mol O ≅ 6 mol O

So the molecular formula for vitamin C is C₆H₈O₆

8 0

3 years ago

Name the postulates of Dalton atomic theory

Elis [28]

Answer:

All matter consists of indivisible particles called atoms. Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements. Atoms cannot be created or destroyed. Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms.

Explanation:

Hope this helps have a great day

8 0

3 years ago

A gas sample occupies 3.25 liters at 297.5K and 2.4 atm. Determine the temperature at which the gas will occupy 4.25 L at 1.50 a

lorasvet [3.4K]

For equal moles of gas, temperature can be calculated from ideal gas equation as follows:

P×V=n×R×T ...... (1)

Initial volume, temperature and pressure of gas is 3.25 L, 297.5 K and 2.4 atm respectively.

2.4 atm ×3.25 L=n×R×297.5 K

Rearranging,

n\times R=0.0262 atm L/K

Similarly at final pressure and volume from equation (1),

1.5 atm ×4.25 L=n×R×T

Putting the value of n×R in above equation,

1.5 atm ×4.25 L=0.0262 (atm L/K)×T

Thus, T=243.32 K

7 0

3 years ago