CHEMISTRY HIGH SCHOOL

Please answer. Brainliest!

Answers

Answer 1

Answer:

The equation is balanced.

Explanation:

The number of P atoms in the reactant side is 4 and the number of P atoms in the product side is also 4.

The number of O atoms in the reactant side is 16 and the number of O atoms in the product side is also 16.

The number of H atoms in the reactant side is 12 and the number of H atoms in the product side is also 12.

These results are in accordance with the law of conservation of mass.

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The action of some commercial drain cleaners is based on the following reaction: 2 NaOH(s) + 2 Al(s) + 6 H2O(l) → 2 NaAl(OH)4(s) + 3 H2(g) What is the volume of H2 gas formed at STP when 6.32 g of Al reacts with excess NaOH?
Examples of chemical changes in nature
What can be said about the polarity of the C=O bond? A) C and O have the same electronegativity; the bond is nonpolar B) the C=O bond is polar; the O atom bears a partial negative charge C) the C=O bond is nonpolar; the C atom bears a partial positive charge D) the C=O bond is polar; the C atom bears a partial negative charge
What is the answer to this one?

Which can be determined using a chemical formula?a. the elements that make up the compound
b. the substances that make up a solution
c. the pH of a solution
d. the boiling point of a compound

Answers

A chemical formula can be directly used to find out the elements that make up the compound. Also, since each chemical compound has a unique boiling point, that can also be determined by just knowing the chemical formula. The answers are:

a. the elements that make up the compound
d. the boiling point of a compound

Answer: a. the elements that make up the compound

Explanation:

Chemical formulas are the symbolic representation of the elements contained in a compound along with their relative proportions.

For example: The chemical formula for water is $H_2o$ which shows that it is formed by combination of hydrogen and oxygen in the ratio of 2: 1 respectively.

pH of the solution is determined by litmus paper, pH paper or pH meter.

Boiling point is the temperature at which atmospheric pressure becomes equal to the atmospheric pressure.

The density of an elemental gas is 1.7824 g/l at stp. what is the molar mass of the element. what is the element?

Answers

Answer: The molar mass of the element is 40 g/mol and element is Calcium.

Explanation:

At STP:

1 mole of a gas contains 22.4 L of volume

Molar mass is defined as the mass of 1 mole of a substance.

To calculate mass of of the substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Volume of gas = 22.4 L

Density of gas = 1.7824 g/L

Putting values in above equation, we get:

$1.7824g/L=\frac{\text{Mass of gas}}{22.4L}\n\n\text{Mass of gas}=(1.7824g/L* 22.4L)=39.9g\approx 40g$

The element having molar mass 40 g is Calcium.

Hence, the molar mass of the element is 40 g/mol and element is Calcium.

At STP 1 mole of gas occupies 22.4L. So you just multiply 1.7824g/L by 22.4L and the Liters cancel out. So the final answer is 39.92 and element Argon is closest to this mass so Argon is the element.

A.) Thermal Decomposition of 2.765 g NaHCO3 yields 1.234g of a solid Na2CO3 . Calculate the theoreticial yield and percent yield of Na2CO3.B) Thermal decomposition of 2.968 g of a mixture containing NaHCO3 lost 0.453 g . Calculate the percentage of NaHCO3 in this unknown mixture

Answers

Answer:

For A: The percent yield of sodium carbonate is 70.5 %

For B: The percent of sodium hydrogen carbonate in the unknown mixture is 15.26 %

Explanation:

For A:

To calculate the number of moles, we use the equation:

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

Given mass of sodium hydrogen carbonate = 2.765 g

Molar mass of sodium hydrogen carbonate = 84 g/mol

Putting values in equation 1, we get:

$\text{Moles of sodium hydrogen carbonate}=(2.765g)/(84g/mol)=0.033mol$

The chemical equation for the thermal decomposition of sodium hydrogen carbonate follows:

$2NaHCO_3(s)\rightarrow Na_2CO_3(s)+CO_2(g)+H_2O(g)$

By Stoichiometry of the reaction:

2 moles of sodium hydrogen carbonate produces 1 mole of sodium carbonate

So, 0.033 moles of sodium hydrogen carbonate will produce = $(1)/(2)* 0.033=0.0165mol$ of sodium carbonate

Now, calculating the mass of sodium carbonate from equation 1, we get:

Molar mass of sodium carbonate = 106 g/mol

Moles of sodium carbonate = 0.0165 moles

Putting values in equation 1, we get:

$0.0165mol=\frac{\text{Mass of sodium carbonate}}{106g/mol}\n\n\text{Mass of sodium carbonate}=(0.0165mol* 106g/mol)=1.75g$

To calculate the percentage yield of sodium carbonate, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}* 100$

Experimental yield of sodium carbonate = 1.234 g

Theoretical yield of sodium carbonate = 1.75 g

Putting values in above equation, we get:

$\%\text{ yield of sodium carbonate}=(1.234g)/(1.75g)* 100\n\n\% \text{yield of sodium carbonate}=70.5\%$

Hence, the percent yield of sodium carbonate is 70.5 %

For B:

To calculate the percentage composition of sodium hydrogen carbonate in mixture, we use the equation:

$\%\text{ composition of sodium hydrogen carbonate}=\frac{\text{Mass of sodium hydrogen carbonate}}{\text{Mass of mixture}}* 100$

Mass of mixture = 2.968 g

Mass of sodium hydrogen carbonate = 0.453 g

Putting values in above equation, we get:

$\%\text{ composition of sodium hydrogen carbonate}=(0.453g)/(2.968g)* 100=15.26\%$

Hence, the percent of sodium hydrogen carbonate in the unknown mixture is 15.26 %

2NaHCO3 -> Na2CO3 + H2O + CO2
2.765g NaHCO3/MM = moles NaHCO3
moles NaHCO3 x (1 mole Na2CO3 / 2 moles NaHCO3) x MM Na2CO3 = theoretical yield of Na2CO3

Percent yield is simply the actual yield/theoretical yield (x100 to put it into percentage).

MM = Molar mass (grams of substance per mol)

How many electrons does calcium lose when forming an ionic bond with another ion?a. 1
b. 2
c. 3
d. 4

Answers

The correct answer is answer choice B, 2. Calcium is in Column 2, meaning that it has 2 electrons in its outermost energy level. These two electrons must be lost for it to form an ionic bond with another element and become stable.

Questions like these can be easily answered if you have a periodic table on hand. Elements in Column 1 need to lose 1 electron to form ionic bonds, elements in Column 2 need to lose 2, and so on. Keep in mind, however, that elements in the center of the table are more likely to form metallic or covalent bonds, and elements in Columns 16 and 17 need to gain 2 and 1 electrons, respectively.

What color represents the highest elevation

Answers

The Color Red Is What People To Represent High Elevation From: 2,000-2,400 m

red is my answer hope I helped you on this :-D :-D :-D

Sequence the following types of waves from lowest frequency to highest frequency: ultraviolet rays, infrared rays, gamma rays, radio waves, and green light. I've looked everywhere and I can't find it!

Answers

Among electromagnetic waves, UV rays are most dangerous because exposure to these radiation cause serious problems in living organism. Therefore, waves from lowest frequency to highest frequency are radio waves, infrared rays, ultraviolet rays and gamma rays.

What is electromagnetic wave?

Electromagnetic wave is a wave which contain two component one is electric component and other is magnetic component. The electric and magnetic component are perpendicular to each other. There are so many wave that comes under electromagnetic wave like infrared wave , radio wave.

There is a relation between energy of wave. frequency of wave, and wavelength of wave

Mathematically,

E=hc/λ

where,

E = energy of electromagnetic wave

h is planks constant having value 6.67×10⁻³⁴js

c is speed of light that is 3×10⁸m/s

λ is the wavelength of electromagnetic wave

Waves from lowest frequency to highest frequency are radio waves, infrared rays, ultraviolet rays and gamma rays.

Therefore, waves from lowest frequency to highest frequency are radio waves, infrared rays, ultraviolet rays and gamma rays.

To know more about electromagnetic wave, here:

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