How many moles are contained in 6.55 x 10^23 formula units of KNO3?

Most elements are ____________. The _____________ elements on the left of the stair-step line on the ______________ of Elements

Vlada [557]

Answer:

metals, 88 , periodic table , luster , heat, electricity , thin, right, opposite , appearance , luster , malleable , ductile, opposite , shiny, moderately

Explanation:

metals, 88 , periodic table , luster , heat, electricity , thin, right, opposite , appearance , luster , malleable , ductile, opposite , shiny, moderately Is the answer.

(Hope this helps can I pls have brainlist (crown)☺️)

4 0

3 years ago

How many grams of CH4 will be in a 500ml contain at STP?

ArbitrLikvidat [17]

Answer:

Mass = 0.32 g

Explanation:

Given data:

Mass of CH₄ = ?

Volume of CH₄ = 500 mL (500 mL× 1L/1000 mL= 0.5 L)

Temperature = 273 K

Pressure = 1 atm

Solution:

Volume of CH₄:

500 mL (500 mL× 1L/1000 mL= 0.5 L)

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K

T = temperature in kelvin

By putting values,

1 atm× 0.5 L = n×0.0821 atm.L/ mol.K × 273 K

0.5 atm.L = n×22.4 atm.L/ mol

n = 0.5 atm.L / 22.4 atm.L/ mol

n = 0.02 mol

Mass in gram:

Mass = number of moles × molar mass

Mass = 0.02 mol × 16 g/mol

Mass = 0.32 g

7 0

3 years ago

Make notes on why did the levels of carbon dioxide in the atmosphere decrease?

kykrilka [37]

Answer:

Carbon dioxide is a very soluble gas. It dissolves readily in water. As the oceans formed, carbon dioxide dissolved to form soluble carbonate compounds so its amount in the atmosphere decreased. Carbonate compounds were then precipitated as sedimentary rocks, eg limestone.

Uptake by living organisms

Carbon dioxide was also absorbed from the oceans into photosynthetic algae and plants. Many of these organisms, and the simple organisms in the food chains that they supported were turned into fossil fuels, eg crude oil, coal and natural gas, which all contain carbon.

Coal is a fossil fuel which was formed from trees which were in dense forests in low-lying wetland areas. Flooding caused the wood from these forests to be buried in a way that prevented oxidation taking place. Compression and heating over millions of years turned the wood into coal.

Crude oil and natural gas were formed from simple plants and tiny animals which were living in oceans and lakes. These small organisms died and their remains sank to the bottom where they were buried under sediments. The lack of oxygen prevented oxidation from occurring.

Over millions of years, heat and pressure turned the remains of the organisms into crude oil and natural gas. Natural gas contains the smallest molecules and is often found on top of crude oil, trapped under sedimentary rock.

Hope this helps..Pls mark as Brainliest!!

5 0

4 years ago

Read 2 more answers

The equilibrium constant is given for two of the reactions below. Determine the value of the missing equilibrium constant. 2A(g)

monitta

Answer:

The value of the missing equilibrium constant ( of the first equation) is 1.72

Explanation:

First equation: 2A + B ↔ A2B Kc = TO BE DETERMINED

⇒ The equilibrium expression for this equation is written as: [A2B]/[A]²[B]

Second equation: A2B + B ↔ A2B2 Kc= 16.4

⇒ The equilibrium expression is written as: [A2B2]/[A2B][B]

Third equation: 2A + 2B ↔ A2B2 Kc = 28.2

⇒ The equilibrium expression is written as: [A2B2]/ [A]²[B]²

If we add the first to the second equation

2A + B + B ↔ A2B2 the equilibrium constant Kc will be X(16.4)

But the sum of these 2 equations, is the same as the third equation ( 2A + 2B ↔ A2B2) with Kc = 28.2

So this means: 28.2 = X(16.4)

or X = 28.2/16.4

X = 1.72

with X = Kc of the first equation

The value of the missing equilibrium constant ( of the first equation) is 1.72

7 0

4 years ago

Which of the following has the strongest buffering capacity? A. H2O B. 0.1 M HCl C. 0.1 M carbonic/bicarbonate (H2CO3/HCO3-) at

enyata [817]

Explanation:

(A) As we know that carbonic acid ( $H_{2}CO_{3}$ ) and Sodium bicarbonate ( $NaHCO_{3}$ ) forms an acidic buffer.

Therefore, pH of an acidic buffer is given by Hendeerson-Hasselbalch equation as follows.

pH = $pK_{a} + log(\frac{[Salt]}{[Acid]})$ ........... (1)

So mathematically, if [Salt] = [Acid] then $\frac{[Salt]}{[Acid]}$ = 1 .

And, $log (\frac{[Salt]}{[Acid]})$ = 0

Therefore, equation (1) gives us the following.

pH = $pK_{a}$ (when acid and salt are equal in concentration)

Hence, $pK_{a}$ of $H_{2}CO_{3}$ (carbonic acid) is 6.35.

And, with this we have following results.

In (A) and (D) we have the case \frac{[NaHCO_{3}]}{[H_{2}CO_{3}]}[/tex] i.e. [Salt] = [Acid].

Hence, for the cases pH = $pK_{a}$ = 6.35.

(B) $[NaHCO_{3}]$ = 0.045 M and, $[H_{2}CO_{3}]$ = 0.45 M

Hence, pH = $6.35 + log([NaHCO_{3}][[H_{2}CO_{3}])$

= $6.35 + log(\frac{0.045}{0.45})$

= 6.35 + (-1)

= 5.35

Therefore, it means that this buffer will be most suitable buffer as it has pH on acidic side and addition of slight excess base will not affect much of its pH value.

(C) $[NaHCO_{3}]$ = 0.45 M $[H_{2}CO_{3}]$

= 0.045 M

So, pH = $6.35 + log(\frac{[NaHCO_{3}]}{[H_{2}CO_{3}]})$

= $6.35 + log(\frac{0.45}{0.045})$

= 6.35 + (+1)

= 7.35

This means that pH on Basic side makes it no more acidic buffer.

5 0

3 years ago