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2 years ago

Maya made this picture to represent a chemical reaction:

Chemistry

1 answer:

Minchanka [31]2 years ago

5 0

Answer:

It is neither a synthesis reaction nor a decomposition reaction because two reactants form two products.

Explanation:

This reaction would be considered a single replacement reaction.

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Select the correct answer. Thomas has 235 grams of K2S in the chemistry lab. How many atoms of potassium (K) are in 235 grams of

Readme [11.4K]

Atoms are the smallest division of the element. The potassium atoms present in the 235 gm of the compound is $2.57 \times 10^{24}$ atoms.

<h3>What is the number of atoms?</h3>

Given,

Mass (m) of Potassium sulfide $(\rm K_{2}S)$ = 235 gm
Molar mass (M) of Potassium sulfide = 110.26 g/mol

Calculate the number of moles as:

$\begin{aligned}\rm Moles (n) &= \dfrac{\rm mass}{\rm molar\;\rm mass}\\\\&= \dfrac{235}{110.26}\\\\&=2.13\;\rm mol\end{aligned}$

In the given compound $\rm K_{2}S$ , there are two atoms of potassium and one atom of sulphur.

If, 1 mole = $2 \times 6.022 \times 10^{23}$ atoms of potassium

Then, 2.13 moles = X atoms

Solving for X:

$2.13 \times 2 \times 6.022 \times 10^{23} = 2.57 \times 10^{24}$

Therefore, option c. $2.57 \times 10^{24}$ is correct.

Learn more about atoms here:

brainly.com/question/11411852

6 0

2 years ago

Find the ph of a 0.250 m solution of nac2h3o2. (the ka value of hc2h3o2 is 1.80×10−5). express your answer numerically to four s

Slav-nsk [51]

Answer is: pH value of solution of NaC₂H₃O₂ is 9.07.
Chemical reaction: C₂H₃O₂⁻ + H₂O ⇄ HC₂H₃O₂ + OH⁻.
Ka(HC₂H₃O₂) = 1,8·10⁻⁵.
Ka · Kb = Kw.
1,8·10⁻⁵ mol/dm³ · Kb = 1·10⁻¹⁴ mol²/dm⁶; the ionic product of water at 25°C.
Kb(C₂H₃O₂⁻) = 1·10⁻¹⁴ mol²/dm⁶ ÷ 1,8·10⁻⁵ mol/dm³.
Kb(C₂H₃O₂⁻) = 5,56·10⁻¹⁰ mol/dm³.
c(C₂H₃O₂⁻) = 0,25 M.
[OH⁻] = [HC₂H₃O₂] = x.
[C₂H₃O₂⁻] = 0,25 M - x.
Kb = [OH⁻] · [HC₂H₃O₂] / [C₂H₃O₂⁻].
5,56·10⁻¹⁰ = x² / (0,25 M -x).
Solve quadratic equation: x = [OH⁻] = 0,0000118 M.
pOH = -log[OH⁻] = -log(0,0000118M) = 4,93.
pH + pOH = 14.
pH = 14 - 4,93 = 9,07.

6 0

3 years ago

A 3.31-g sample of lead nitrate, Pb(NO3)2, molar mass = 331 g/mol, is heated in an evacuated cylinder with a volume of 2.53 L. T

Dahasolnce [82]

Answer:

0.486atm is the pressure of the cylinder

Explanation:

1 mole of Pb(NO₃)₂ descomposes in 4 moles of NO2 and 1 mole of O2. That is 1 mole descomposes in 5 moles of gas.

To find the pressure of the cylinder, we need to find moles of gas produced, and using general gas law we can determine the pressure of the gas:

Moles Pb(NO₃)₂ and moles of gas:

3.31g * (1mol / 331g) = 0.01 moles of Pb(NO₃)₂.

That means moles of gas produced is 0.05 moles.

Pressure of the gas:

Using PV = nRT

P = nRT/V

Where P is pressure (Incognite)

V is volume (2.53L)

R is gas constant (0.082atmL/molK)

T is absolute temperature (300K)

And n are moles of gas (0.05 moles)

P = 0.05mol*0.082atmL/molK*300K / 2.53L

P = 0.486atm is the pressure of the cylinder

3 0

2 years ago

Is baking soda a fine powder or is it coarse

sp2606 [1]

Baking soda is a fine powder because when you touch it the baking soda is very soft

8 0

3 years ago

The enthalpies of formation of the compounds in the combustion of methane, , are CH4 (g): Hf = –74.6 kJ/mol; CO2 (g): Hf = –393.

algol [13]

Answer:

The amount of energy released from the combustion of 2 moles of methae is 1,605.08 kJ/mol

Explanation:

The chemical reaction of the combustion of methane is given as follows;

CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (g)

Hence, 1 mole of methane combines with 2 moles of oxygen gas to form 1 mole of carbon dioxide and 2 moles of water vapor

Where:

CH₄ (g): Hf = -74.6 kJ/mol

CO₂ (g): Hf = -393.5 kJ/mol

H₂O (g): Hf = -241.82 kJ/mol

Therefore, the combustion of 1 mole of methane releases;

-393.5 kJ/mol × 1 + 241.82 kJ/mol × 2 + 74.6 kJ/mol = -802.54 kJ/mol

Hence the combustion of 2 moles of methae will rellease;

2 × -802.54 kJ/mol or 1,605.08 kJ/mol.

8 0

2 years ago

Read 2 more answers