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3 years ago

Match each body system with its main organ.

Chemistry

1 answer:

olya-2409 [2.1K]3 years ago

7 0

Answer:

it's in the explanation

Explanation:

Lungs- Respiratory

Heart- Circulatory

Brain- Nervous

Stomach- Digestive

Bladder- Excretory

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What is the freezing point of an aqueous solution that has 25.00 g of calcium iodide dissolved in 1250 g of water?

ozzi

Answer:

- 0.380ºC

Explanation:

The lowering of the freezing point of a solvent is a colligative property ruled by the formula:

$\Delta T_f=K_f\times m\times i$

Where:

ΔTf is the lowering of the freezing point

Kf is the molal freezing constant of the solvent: 1.86 °C/m

m is the molality of the solution

i is the van't Hoff factor: the number of particles (ions) per unit of ionic compound.

a) molality, m

m = number of moles of solute/ kg of solvent

number of moles of CaI₂ = mass in grams/ molar mass

number of moles of CaI₂ = 25.00g / 293.887 g/mol = 0.0850667mol

m = 0.0850667mol/1.25 kg = 0.068053m

b) i

Each unit of CaI₂, ideally, dissociates into 1 Ca⁺ ion and 2 I⁻ ions. Thus, i = 1 + 2 = 3

c) Freezing point lowering

ΔTf = 1.86 °C/m × 0.068053m × 3 = 0.3797ºC ≈ 0.380ºC

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6 0

3 years ago

What is the difference between atomic mass, relative atomic mass and average atomic mass

vesna_86 [32]

$\bold{\huge{\underline{\purple{ Answer }}}}$

Difference between Atomic mass, relative atomic mass and average atomic mass :-

<h3>Atomic Mass :-</h3>

Atomic mass is the mass of neutrons and protons present in the nucleus of an atom .
It is always calculated for a single element and having direct value
For isotopes also, the atomic mass is calculated separately . Example :- Carbon 12 , carbon 13 and carbon 14 have different atomic mass. 
The SI unit of Atomic mass is " u" and "amu"

<h3>Relative Atomic mass :-</h3>

Relative atomic mass is mean mass of the atoms of an element which is compared to the 1/12th mass of carbon - 12 .
Carbon - 12 is taken as a relative when we calculate the relative atomic mass of any element
For calculating relative atomic mass, we need to know the masses, percentage and abundance of all types of elements
Relative atomic mass is a dimension less quantity

<h3>Average Atomic Mass :-</h3>

Average atomic mass is the average mass of an atoms of a particular element by considering it's isotopes
While we calculate average atomic mass is a standardized number. Whereas, Average atomic mass sometimes varies geologically .
It also includes percentage, abundance and masses of given element .
In average atomic mass, We do not compare mean value with the 1/12 mass of carbon - 12
The unit of Average atomic mass is "Amu" or " u " .

5 0

2 years ago

What is the molarity of a solution in which 25g NaCl in a 2.00 L solution?

Paladinen [302]

Mass of sodium :- 23 grams

Mass of Chlorine :- 35.5 grams

Mass of NaCl :- 58.5 grams

mass given :- 25 grams

moles :- 0.432 ( given mass/ ionic mass)

$molarity = \frac{moles}{vol} \\ molarity = \frac{0.432}{2} \\ molarity = 0.216 \: mole{l}^{ - 1} or \: molar$

5 0

2 years ago

Which element does not have the same number of electrons in its outermost shell as the other elements in its group?(1 point)

Natalija [7]

Answer:

Helium

Explanation:

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2 years ago

What type of solvent would be required to dissolve nonpolar compounds?

mina [271]

For example, ionic compounds, which are very polar, are often soluble in the polar solvent water. Nonpolar substances are likely to dissolve in nonpolar solvents. For example, nonpolar molecular substances are likely to dissolve in hexane, a common nonpolar solvent.

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1 year ago

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