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1 year ago

How many grams of potassium chloride (KCI) are needed to prepare 0.750 L of a 1.50 M solution of potassium chloride in water?

1 answer:

8 0

KCl: 74.5g/mol

Molarity = mol/Liters
Since you are given 0.750L and 1.50M, we can plug it into the molarity formula and solve for moles.

1.50M = x mol/0.750L
X = 1.125 moles of KCl needed

You asked for grams so let’s convert the moles of KCl to grams:

1.125 mol x (74.5g/mol) = 83.8g KCl

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If an element has 2+ valence electrons, does it transfer only one or more than one valence electrons

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Answer:

element having 2+ valence electrons can transfer its more than one electron that is 2 electron completely.

Explanation:

Group IIA have 2+ valency and two electrons in its valance shell.

Its Electropositivity is high and have the tendency to donate it two electrons.

Element of IIA form ionic with most electronegative element.

Examples:

Cu²⁺, Mg²⁺, Sr²⁺ are examples having 2+ valance electron

one of the following is examples of element that have 2+ valence electrons

MgCl₂

Atomic number of Magnesium (Mg) is 12

Electronic Configuration of Mg:

1s², 2s², 2p⁶, 3s²

K =2

L = 8

M = 2

So, it have to give its 2 electrons to form a stable compound.

Similarly

Chlorine atomic number is 17

Electronic Configuration of Chlorine:

1s², 2s², 2p⁶, 3s², 3p⁵

K =2

L = 8

M = 7

So, it have to gain one electrons to form a stable compound and complete its octet.

So,

Two chlorine atom as a molecule gain 2 electrons from Mg²⁺ atom

So one Mg²⁺ and 2 Cl⁻ atoms form an ionic bond

where in this ionic bond Mg²⁺ transfer its 2 valence electron completely and chlorine molecule accept 2 electrons.

Cl-----Mg------Cl

So the Answer is

element having 2+ valence electrons can transfer its more than one electron that is 2 electron completely.

8 0

2 years ago

Why does water have a lopsided shape and act like a chemical magnet?

leva [86]

Answer:

See below

Step-by-step explanation:

(a) Shape

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The central O atom has four electron pairs around it. They try to get as far from each other as possible, so they point toward the corners of a tetrahedron.

Only two of the pairs have a hydrogen atom attached, so water has a bent shape. The H-O-H bond angle is about 104°.

(b) Chemical magnet

The O atom has a greater attraction than H for the shared electrons in the O-H bonds, so the electrons spend more time near the O.

This gives the O atom a partial negative charge (pink in the diagram) and the H atoms a partial positive charge (blue).

The water molecule acts like a chemical magnet because its negative end attracts the positive ends of other molecules, while its positive ends attract the negative ends of other molecules.

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2 years ago

An archaeologist graduate student found a leg bone of a large animal during the building of a new science building. The bone had

Vlad [161]

Answer : The time passed in years is $2.74\times 10^2\text{ years}$

Explanation :

Half-life of carbon-14 = 5730 years

First we have to calculate the rate constant, we use the formula :

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{5730\text{ years}}$

$k=1.21\times 10^{-4}\text{ years}^{-1}$

Now we have to calculate the time passed.

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = $1.21\times 10^{-4}\text{ years}^{-1}$

t = time passed by the sample = ?

a = initial amount of the reactant disintegrate = 15.3

a - x = amount left after decay process = 14.8

Now put all the given values in above equation, we get

$t=\frac{2.303}{1.21\times 10^{-4}}\log\frac{15.3}{14.8}$

$t=274.64\text{ years}=2.74\times 10^2\text{ years}$

Therefore, the time passed in years is $2.74\times 10^2\text{ years}$

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3 years ago

Which property is shared between liquids that are used in thermometers.

miv72 [106K]

Answer:

the property that is shared between liquids us called thermometric property your welcome

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2 years ago

What important points do you need to remember about combustion?

goldenfox [79]

Explanation:

A substance burning in the presence of oxygen and leads to the formation of heat and light is called combustion.

Some important points about combustion are as follows:

Fuel should be present for burning.
Air should be present for the supply of oxygen.
There should be heat (or ignition temperature) to initiate the chemical reaction.

7 0

2 years ago

How many grams of potassium chloride (KCI) are needed to prepare 0.750 L of a 1.50 M solution of potassium chloride in water?​

How many grams of potassium chloride (KCI) are needed to prepare 0.750 L of a 1.50 M solution of potassium chloride in water?