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4 years ago

9

What species is undergoing reduction in the following reaction? NO3-(aq) + 4Zn(s) + 7OH-(aq) + 6H2O(l) → 4Zn(OH)42-(aq) + NH3(aq

)

1 answer:

RUDIKE [14]4 years ago

4 0

Zn because it gains electrons

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A molecule with 14 total electrons and 12 total protons

Snowcat [4.5K]

Answer:

Explanation:

Tenochtitlan was located on a swampy island in Lake Texcoco in what is today south central Mexico. The Aztecs were able to settle there because no one else wanted the land. At first, it wasn't a great place to start a city, but soon the Aztecs built up islands where they could grow crops. The water also worked as a natural defense against attacks from other cities.

Read more at: https://www.ducksters.com/history/aztec_empire/tenochtitlan.php

This text is Copyright © Ducksters. Do not use without permission.

5 0

3 years ago

What some everyday ways we use nuclear power? What are the pros and cons of using nuclear power? (Three each)

eimsori [14]

Answer:

Explanation:

Pro – Low carbon. Unlike traditional fossil fuels like coal, nuclear power does not produce greenhouse gas emissions like methane and CO2. ...

Con – If it goes wrong… ...

Pro – Not intermittent. ...

Con – Nuclear waste. ...

Pro – Cheap to run. ...

Con – Expensive to build

4 0

3 years ago

Determine the empirical formula of a compound containing 48.38 grams of carbon, 6.74 grams of hydrogen, and 53.5 grams of oxygen

Darya [45]

Answer: The empirical formula of the compound becomes $CH_2O$

<u>Explanation:</u>

The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.

We are given:

Mass of C = 48.38 g

Mass of H = 6.74 g

Mass of O = 53.5 g

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

To formulate the empirical formula, we need to follow some steps:

<u>Step 1:</u> Converting the given masses into moles.

Molar mass of C = 12 g/mol

Molar mass of H = 1 g/mol

Molar mass of O = 16 g/mol

Putting values in equation 1, we get:

$\text{Moles of C}=\frac{48.38g}{12g/mol}=3.023 mol$

$\text{Moles of H}=\frac{6.74g}{1g/mol}=6.74 mol$

$\text{Moles of O}=\frac{53.5g}{1g/mol}=3.34 mol$

<u>Step 2:</u> Calculating the mole ratio of the given elements.

Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 3.023 moles

$\text{Mole fraction of C}=\frac{3.023}{3.023}=1$

$\text{Mole fraction of H}=\frac{6.74}{3.023}=2.23\approx 2$

$\text{Mole fraction of O}=\frac{3.34}{3.023}=1.105\approx 1$

<u>Step 3:</u> Taking the mole ratio as their subscripts.

The ratio of C : H : O = 1 : 2 : 1

Hence, the empirical formula of the compound becomes $CH_2O$

5 0

3 years ago

Caffeine, a stimulant found in coffee and soda, hasthe mass percent composition: C. 49.48%, H, 5.19%. N. 28.85% 0. 16.48% The mo

borishaifa [10]

We have the next % composition:

C. 49.48%

H, 5.19%.

N. 28.85%

0. 16.48%

We assume 100 g of sample

1) As we have 100 g of sample of Caffeine, we calculate the mass of each element involved here.

C. 49.48 g

H, 5.19 g

N. 28.85 g

0. 16.48 g

2) We calculate the number of moles of each element (we need the mass per mole of each element)

For C) 12.01 g/mol

49.48 g x (1 mol/12.01 g) = 4.120 moles

For H) 1.007 g/mol

5.19 g x (1 mol/1.007 g) = 5.154 moles

For O) 15.99 g/mol

16.48 g x (1 mol/15.99 g) = 1.030 moles

For N) 14.00 g/mol

28.85 g x (1 mol/14.00 g) = 2.060 moles

3) We choose the smallest number from 2) and divide the rest of them by it.

For C) 4.120 moles/1.030 moles= 4

For H) 5.154 moles/1.030 moles= 5

For O) 1.030 moles/1.030 moles= 1

For N) 2.060 moles/1.030 moles= 2

4) The numbers in 3) represents the subindex from the empirical formula of caffeine:

$C_4H_5O_1N_2$

5) We calculate the molar mass of our empirical formula, 97.06 g/mol.

We already have the molar mass of the molecular formula, so we proceed like this:

n= the molar mass of the molecular formula/the molar mass of the empirical formula

n = 194.19 g/mol/97.06 g/mol = 2 approx.

We use "n" and we multiply our empirical formula by n = 2:

Therefore, our molecular formula:

$C_8H_{10}O_2N_4$

8 0

1 year ago

Measurements show that the ph of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?

fomenos

Answer: Hydrogen ion concentration of the lake is $10^{-4}M$

Explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration. Acids have pH ranging from 1 to 6.9 and bases have pH ranging from 7.1 to 14.

To calculate the pH of the solution, we use the equation:

$pH=-\log[H^+]$

We are given:

pH = 4.0

Putting values in above equation, we get:

$4.0=-\log[H^+]$

$[H^+]=10^{-4.0}$

$[H^+]=10^{-4}$

Thus hydrogen ion concentration of the lake is $10^{-4}M$

6 0

3 years ago