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3 years ago

PLEASE HELP ME!!

Chemistry

1 answer:

ivann1987 [24]3 years ago

6 0

Answer: K and Mg

Explanation:

The first one refers to the atomic radius and increases going down and to the left on the periodic table. K is in between Rb and Na.

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Which set of characteristics listed below are unique to the inner<br> planets?

Cerrena [4.2K]

Mercury,Mars,Venus,Earth

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4 years ago

When hydrochloric acid is poured over potassium sulfide, 42.5 mL of hydrogen sulfide gas is produced at a pressure of 756 torr a

EastWind [94]

<h2>Answer:</h2> $0.1899grams$

<h2>Explanations:</h2>

The balanced chemical reaction between hydrochloric acid and potassium sulfide is as shown:

$K_2S+2HCl\to H_2S+2KCl$

Based on stoichiometry, we can see that 1 mole of potassium sulfide reacted to form 1 mole of hydrogen sulfide.

Get the mole of hydrogen sulfide gas (H2S) using the ideal gas equation expressed as:

$\begin{gathered} PV=\text{nRT} \\ n=\frac{PV}{RT} \end{gathered}$

P is the pressure of the gas (in atm) = 0.994737atm (756torr)

V is the volume of the gas = 42.5mL = 0.0425L

T is the temperature (in Kelvin) = 26 + 273 = 299K

R is the gas constant = 0.0821 L*atm/mole * K

Substitute these values into the formula as shown:

$\begin{gathered} n=\frac{0.994737\cancel{\text{atm}}\times0.0425\cancel{L}}{0.0821\frac{\cancel{L}\cdot\cancel{\text{atm}}}{\text{mole}\cdot\cancel{K}}\times299\cancel{K}} \\ n=\frac{0.994737\times0.0425}{0.0821\times299} \\ n=\frac{0.0422763225}{24.5479} \\ n=0.00172\text{moles} \end{gathered}$

Since the number of moles of hydrogen sulfide is 0.00172moles, the number of moles of potassium sulfide will also be 0.00172 moles (based on stoichiometry)

Get the mass of potassium sulfide that reacted using the formula:

$\text{Mass}=number\text{ of moles}\times molar\text{ mass}$

Number of moles of K2S = 0.00172 moles

Molar mass of K2S = 110.262 g/mol

Substitute into the formula for calculating the mass;

$\begin{gathered} \text{Mass}=0.00172\cancel{\text{moles}}\times\frac{110.262g}{\cancel{\text{mole}}} \\ \text{Mass}=0.1899\text{grams} \end{gathered}$

Therefore the mass of potassium sulfide that reacted (in grams) is approximately 0.1899grams

3 0

1 year ago

True or false: The higher the concentration of a substance in a chemical reaction, the faster the reaction rate will be

xenn [34]

Answer:

true

Explanation:

It's true man..............true.........

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3 years ago

How could the survivors about starting a fire?

joja [24]

Answer:

The ancient Greeks believed that fire was one the four basic elements that composed all things in the universe. In the mythology of virtually every culture, fire is a sacred substance that gives life or power. Fire is not, in fact, a substance. When you gaze at the leaping flames of a campfire, you’re observing not an object, but a process – a chemical reaction. It’s the same chemical reaction that occurs when a cut apple left on the counter turns brown, when silver tarnishes or when an iron nail rusts.

That process is oxidation: combining oxygen with another substance. The defining difference between a fire and your half-eaten apple is speed: fire is an oxidation process that happens very fast, so that light, heat and sound are released — often with enough force and majesty to justify the ancients’ reverence.The sudden release of energy causes temperatures to rise, sometimes by thousands of degrees. And it also results in smoke, the toxic waste of fire’s leftovers.

The fire triangle and the fire tetrahedron

Fire TetrahedronThe fire triangle identifies the three needed components of fire:

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heat (enough to make the fuel burn)

and air (oxygen)

Explanation: i hope this helps sry its long

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4 years ago

An automobile travels 34.0 miles per gallon. How many kilometers does it travel per liter of gasoline? Use these equalities: 1 m

lisov135 [29]

To convert on unit to another unit, a conversion factor is needed to multiply in the value given. For the value given above, we have to convert it from miles per gallon to kilometers per liter. The factors to be used are:

1 mile = 1.61 kilometers;
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<span>34.0 miles / gallon ( 1.61 kilometers / 1 mile ) ( 1 gallon / 3.79 L ) = 14.44 kilometer / liter</span>

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4 years ago