Which of the following substances would be a good electrical conductor? A. KCl(s) B. C(s) C. Al(s) D. CO2(s)

A silver cube with an edge length of 2.38 cm and a gold cube with an edge length of 2.79 cm are both heated to 81.9 ∘C and place

never [62]

Answer:

The final temperature of the water when thermal equilibrium is reached is 23.54 ⁰C

Explanation:

Given data;

edge length of silver, a = 2.38 cm = 0.0238 m

edge length of gold, a = 2.79 cm = 0.0279 m

final temperature of silver, t = 81.9 ° C

final temperature of Gold, t = 81.9 ° C

initial temperature of water, t = 19.6 ° C

volume of water, v = 109.5 mL = 0.0001095 m³

Known data:

density gold 19300 kg/m³

density silver 10490 kg/m³

density water 1000 kg/m³

specific heat gold is 129 J/kgC

specific heat silver is 240 J/kgC

specific heat water is 4200 J/kgC

Calculated data

Apply Pythagoras theorem to determine the side of each cube;

Silver cube;

let L be the side of the silver cube

Taking the cross section of the cube (form a right angled triangle), the edge length forms the hypotenuse side.

L² + L² = 0.0238²

2L² = 0.0238²

L² = 0.0238² / 2

L² = 0.00028322

L = √0.00028322

L = 0.0168

Volume of cube = L³

Volume of the silver cube = (0.0168)³ = 4.742 x 10⁻⁶ m³

Gold cube;

let L be the side of the gold cube

L² + L² = 0.0279²

2L² = 0.0279²

L² = 0.0279² / 2

L² = 0.0003892

L = √0.0003892

L = 0.0197

Volume of cube = L³

Volume of the silver cube = (0.0197)³ = 7.645 x 10⁻⁶ m³

Mass of silver cube;

density = mass / volume

mass = density x volume

mass of silver cube = 10490 (kg/m³) x 4.742 x 10⁻⁶ (m³) = 0.0497 kg

Mass of Gold cube

mass of gold cube = 19300 (kg/m³) x 7.645 x 10⁻⁶ (m³) = 0.148 kg

Mass of water

mass of water = 1000 (kg/m³) x 0.0001095 (m³) = 0.1095 kg

Let the heat gained by cold water be Q₁

Let the heat lost by silver cube = Q₂

Let the heat lost by gold cube = Q₃

Let the final temperature of water = T

Q₁ = 0.1095 kg x 4200 J/kgC x (T–19.6)

Q₂ = 0.0497 kg x 240 J/kgC x (81.9–T)

Q₃ = 0.148 kg x 129 J/kgC x (81.9–T)

At thermal equilibrium;

Q₁ = Q₂ + Q₃

0.1095 x 4200 (T–19.6) = 0.0497 x 240 x (81.9–T) + 0.148 x 129 x (81.9–T)

459.9 (T–19.6) = 11.928 (81.9–T) + 19.092(81.9–T)

459.9T - 9014.04 = 976.9032 - 11.928T + 1563.6348 - 19.092T

459.9T + 11.928T + 19.092T = 9014.04 + 976.9032 + 1563.6348

490.92T = 11554.578

T = 11554.578 / 490.92

T = 23.54 ⁰C

Therefore, the final temperature of the water when thermal equilibrium is reached is 23.54 ⁰C

6 0

3 years ago

Which type of acetylcholine receptor is present on postganglionic neurons

Sonja [21]

Answer:

Mescarinic and Nicotinic

Explanation:

Postganglionic fibers can be present in both sympathetic and parasympathetic divisions, their main difference resides in how in the sympathetic division the postganglionic fibers are adrenergic and use norepinephrine (noradrenalin) as a neurotransmitter, in the parasympathetic division, on the other hand, fibers are cholinergic and use acetylcholine as a neurotransmitter, the postganglionic neurons of sweat glands release acetylcholine for the activation of muscarinic receptors, another kind of receptor for acetylcholine are nicotinic receptors that act as transmembrane sodium/potassium channels, while muscarinic receptors need to act through intracellular proteins.

I hope you find this informatiou useful and interesting! Good luck!

4 0

3 years ago

If someone consumes 22 g of sodium chloride per day, what mass (in grams) of sodium does that person consume? Sodium chloride is

kompoz [17]

Answer:

Mass of sodium, the person daily consume = 8.58 g

Explanation:

Given that:-

sodium chloride is 39% sodium by mass which means that:-

100 g of sodium chloride contains 39 g of sodium

Also,

1 g of sodium chloride contains 0.39 g of sodium

So, Given mass = 22 g

22 g of sodium chloride contains $0.39\times 22$ g of sodium

Mass of sodium, the person daily consume = 8.58 g

4 0

3 years ago

50.0 mL of an HNO^3 solution were titrated with 36.90 mL of a 0.100 M LiOH solution to reach the equivalence point. What is the

NISA [10]

Answer:

0.0738 M

Explanation:

HNO3 +LiOH = LiNO3 + H2O

Number of moles HNO3 = number of moles LiOH

M(HNO3)*V(HNO3) = M(LiOH)*M(LiOH)

M(HNO3)*50.0mL = 0.100M*36.90 mL

M(HNO3) = 0.100*36.90/50.0 M = 0.0738 M

6 0

3 years ago

How does the tendency of iron to rust depend on ph?

mojhsa [17]

The tendency of iron to rust depend on the Ph of solution

The formation of rust increases as the PH decreases. This led agent of rusting that is oxygen gets more positive as H+ ions increase which facilitate rusting. The lower the Ph level the quick the corrosion.

6 0

2 years ago

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