Any change in average weather conditions on Earth that lasts for at least several decades is called

Un camion que circula a 90 km hora frena uniformemente con una aceleracion de -5 metros por segundos al cuadrado

kozerog [31]

Answer:

no habla espanol

Explanation:

7 0

2 years ago

If the sample has a total mass of 5.76 g and contains 1.79 g k, what are the percentages of kbr and ki in the sample by mass

Luden [163]

The percentages of KBr and KI in the sample by mass is 80.68 and 19.32 % respectively.

<h3>What is Molar Mass ?</h3>

Molar mass is defined as the mass contained in 1 mole of sample.

It is given that

the sample has a total mass of 5.76 g contains KBr and KI

and contains 1.79 gm of K is present

what is the percentage of KBr and KI in the sample

Molecular weight of K = 39

Molecular weight of Br = 79.9

Molecular weight of I = 126.9

In KBr the mass percentage of K is 39/(39+79.9) = 32.89%

In KI the mass percentage of K is 39/(39+126.9) = 23.5%

Let the mass of KBr present in the sample is x

K will be 0.3289 x

and let the mass of KI present be y

K will be 0.235y

x +y =5.76

0.3289x+0.235y = 1.79

0.0939y = 0.1045

y = 1.1125 gm

x = 5.76-1.1125

x = 4.6475 gm

% of KBr = (4.6475/5.76 )*100 = 80.68 %

% of KI = (1.1125/5.76) *100 = 19.32%

To know more about Molar Mass

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8 0

2 years ago

4. Nowadays, clinical thermometer is replaced by digital thermometer,why?<br>

White raven [17]

Answer:

<h2>Digital thermometer are used these days instead of clinical thermometers because: Digital thermometers are designed to be more accurate. Most digital thermometers have digital screening which extract temperature of wherever you are measuring. </h2>

4 0

3 years ago

What happens at the cathode in an electrolytic cell?<br><br> (Answer is reduction)

melisa1 [442]

Answer:

At the cathode in an electrolytic cell, ions in the surrounding solution are reduced into atoms, which precipitate or plate out on to the solid cathode. The anode is where oxidation takes place, and the cathode is where reduction takes place.

Explanation:

7 0

3 years ago

Read 2 more answers

Determine the quantity of bromine atoms in 18.0g of HgBr2 (using factor label method)

Gnoma [55]

Considering the definition of molar mass and Avogadro's Number, the quantity of bromine atoms in 18.0g of HgBr₂ is 6.023×10²² atoms.

<h3>Definition of molar mass</h3>

The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.

The molar mass of a compound (also called Mass or Molecular Weight) is the sum of the molar mass of the elements that form it (whose value is found in the periodic table) multiplied by the number of times they appear in the compound.

<h3>Molar mass of HgBr₂</h3>

In this case, you know the molar mass of the elements is:

Hg= 200 g/mole
Br= 79.9 g/mole

So, the molar mass of the compound HgBr₂ is calculated as:

HgBr₂= 200 g/mole + 2×79.9 g/mole

Solving:

HgBr₂= 359.98 g/mole

Definition of Avogadro's Number

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.

<h3>Quantity of bromine atoms in 18.0g of HgBr₂</h3>

Factor-label describes a technique to convert one quantity to another quantity. This method uses the fact that any number or expression can be multiplied by one without changing its value; this is, consists in multiply the value you are given, unit of measurement included, by the conversion factor in fraction form.

Finally, knowing that 2 moles of Br are present in 1 mole of HgBr₂, and considering the molar mass of HgBr₂ and the definition on Avogadro's number, the quantity of bromine atoms in 18.0g of HgBr₂ is calculated as:

$18 gr HgBr_{2}\frac{1 mole HgBr_{2}}{359.98 gHgBr_{2}} \frac{2 mole Br}{1 mole HgBr_{2} } \frac{6.023x10^{23}atoms Br }{1 mole Br} =6.023x10^{22}atoms$

In summary, the quantity of bromine atoms in 18.0g of HgBr₂ is 6.023×10²² atoms.

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8 0

2 years ago