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3 years ago

Describe the day of June 21 at the North Pole in terms of daylight and darkness ( science )

1 answer:

7 0

On June 21, as seen from the North pole ...

-- the sun has been up, and it's been light outside,
for the past three months ... ever since March 21 .

-- The sun won't set, and it won't be dark outside,
for another three months ... until September 21.

-- Here at the North pole, it stays daylight for six months straight.
Today, on June 21, we're exactly halfway through the period of
continuous daylight.

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What happens in a voltaic cell?

nirvana33 [79]

Answer:

Hi ,

Answer:

A chemical energy is changed to a electrical energy

3 0

3 years ago

A solution is made by dissolving 4.87 g of potassium nitrate in water to a final volume of 86.4 mL solution. What is the weight/

lara31 [8.8K]

Answer:

A solution is made by dissolving 4.87 g of potassium nitrate in water to a final volume of 86.4 mL solution. The weight/weight % or percent by mass of the solute is :

2.67%

Explanation:

Note : Look at the density of potassium nitrate in water if given in the question.

You are calculating weight /Volume not weight/weight % or percent by mass of the solute

Here the weight/weight % or percent by mass of the solute is asked : So first convert the VOLUME OF SOLUTION into MASS

Density of potassium nitrate in water KNO3 = 2.11 g/mL

$density=\frac{mass}{volume}$

Density = 2.11 g/mL

Volume of solution = 86.4 mL

$2.11=\frac{mass}{86.4}$

$mass = 2.11\times 86.4$

$mass=182.3grams$

Mass of Solute = 4.87 g

Mass of Solution = 183.2 g

w/w% of the solute =

$= \frac{mass\ of\ solute}{mass\ of\ solution}\times 100$

$=\frac{4.87}{183.2}\times 100$

w/w%=2.67%

8 0

3 years ago

What would the formula of gallium bromide be?

Free_Kalibri [48]

GaBr3

Gallium=Ga
Bromine= Br
Bromide=Br3

5 0

3 years ago

The pH at the equivalence point will be a. less than 7.00 b. equal to 7.00 Allohalineup of a sto quivalence point of a titration

True [87]

Answer: c. greater than 7.00

Explanation: The equivalence point of a titration is when all the base is consumed by the acid. When a strong base and a strong acid react, the medium is neutralized because is produced water and salt (which won't suffer hydrolysis). How water's pH is 7, in this type of titration the pH of the equivalence point will be at pH=7. But on titration of a weak acid with a strong base, the reaction of the equivalence point produces water and the conjugate base of the acid. Because the acid is weak, their conjugate base will be strong and will suffer hydrolysis, producing hydroxyl ions, elevating the pH of the water and making it greater than 7.

8 0

3 years ago

Which of these pairs indicates an incorrect coupling of reversible reactions?dehydration synthesis and hydrolysisanabolic and ca

Olegator [25]

Answer:

option C= hydrolysis and break down

Explanation:

All other three pairs are correct coupling of each others.

Option A= dehydration synthesis and hydrolysis

Dehydration synthesis:

In dehydration synthesis monomers combine through the covalent bonds and form large molecules. The large molecules are called polymers. The water as a byproduct also released when monomers joints together.

Hydrolysis:

In hydrolysis the polymers are break down into monomers by using water molecules. The catalysts are also required in this process.

Option B= Catabolic and Anabolic

Anabolic:

In this process smaller molecules combine to gather to form large complex molecules by using energy.

For example simple glucose molecules join together to form large disaccharides.

Catabolic:

It is the break down of large complex molecules to the smaller molecules.

For example during cellular respiration sugar molecules break down and generate energy.

Option D= Break down and synthesis

The break down and synthesis are also reverse pair of each others. The synthesis involve the formation of molecules form smaller component while the break down involve destruction of molecules into smaller units.

8 0

3 years ago