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3 years ago

5

Analyze how friction can be both a positive and negative aspect in our everyday lives. Use examples to support your statements.

1 answer:

3241004551 [841]3 years ago

8 0

Answer:

For example, friction between our shoes and the floor stop us from slipping and friction between tyres and the road stop cars from skidding. Friction is sometimes unhelpful. For example, if you don't lubricate your bike regularly with oil, the friction in the chain and axles increases.

Explanation:

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Why do waves move faster at higher temperatures and in a solid phase?

podryga [215]

<span>There is more energy and the particles are closer together.</span>

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3 years ago

Read 2 more answers

List two detection (i.e. visualisation) techniques commonly used to visualise<br> compounds in TLC.

olya-2409 [2.1K]

Answer:

The most common non-destructive visualization method for TLC plates is ultraviolet (UV) light. A UV lamp can be used to shine either short-waved (254nm) or long-waved (365nm) ultraviolet light on a TLC plate with the touch of a button

Explanation:

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3 years ago

A pycnometer is a precisely weighted vessel that is used for highly accurate density determinations. Suppose that a pycnometer h

dexar [7]

Answer:

5.758 is the density of the metal ingot in grams per cubic centimeter.

Explanation:

1) Mass of pycnometer = M = 27.60 g

Mass of pycnometer with water ,m= 45.65 g

Density of water at 20 °C = d = $998.2 kg/m^3$

1 kg = 1000 g

$1 m^3=10^6 cm^3$

$998.2 kg/m^3=\frac{998.2 \times 1000 g}{10^6 cm^3}=0.9982 g/cm^3$

Mass of water ,m'= m - M = 45.65 g - 27.60 g =18.05 g

Volume of pycnometer = Volume of water present in it = V

$Density=\frac{Mass}{Volume}$

$V=\frac{m'}{d}=\frac{18.05 g}{0.9982 g/cm^3}=18.08 cm^3$

2) Mass of metal , water and pycnometer = 56.83 g

Mass of metal,M' = 9.5 g

Mass of water when metal and water are together ,m''= 56.83 g - M'- M

56.83 g - 9.5 g - 27.60 g = 19.7 g

Volume of water when metal and water are together = v

$v=\frac{m''}{d}=\frac{19.7 g}{0.9982 g/cm^3}=19.73 cm^3$

Density of metal = d'

Volume of metal = v' = $\frac{M'}{d'}$

Difference in volume will give volume of metal ingot.

v' = v - V

$v'=19.73 cm^3-18.08 cm^3=$

$v'=1.65 cm^3$

Since volume cannot be in negative .

Density of the metal =d'

= $d'=\frac{M'}{v'}=\frac{9.5 g}{1.65 cm^3}=5.758 g/cm^3$

5 0

3 years ago

The dissolution of calcium chloride in water is given by the following equation:

never [62]

Answer:

The reactants would appear at a higher energy state than the products.

Have a nice day!

8 0

2 years ago

The tiara worn by Kate Middleton for her wedding to Prince William of England contains 888 diamonds and belongs to the British m

allsm [11]

Answer:

The number of atoms in the gemstones of that tiara is $8.9125\times 10^{24} atoms$ .

Explanation:

Number of diamonds ion tiara = 888

Mass of each diamond = 1.0 carat = 0.200 g (given)

Mass of 888 diamonds in tiara:

$888\times 0.200 g=177.600 g$

Given that diamond is a form of carbon.

Atomic mass of carbon atom = 12 g/mol

Moles of 77.600 g of carbon = $\frac{177.600 g}{12 g/mol}=14.800 mol$

Number of atoms of carbon 14.800 moles:

$14.800 mol\times 6.022\times 10^{23} atoms =8.9125\times 10^{24} atoms$

The number of atoms in the gemstones of that tiara is $8.9125\times 10^{24} atoms$ .

5 0

3 years ago