All elements have a AHf, of ___
kJ/mole at standard temperature and pressure.
a. 1
b. 4.184
c. 273
d. 0

Answers

Answer 1

All elements have a AHf, of 0

kJ/mole at standard temperature and pressure.

What is an element?

An element can be defined as a substance which cannot be split into two or more simpler forms by an ordinary chemical process

Below are the list of the first twenty elements:

HydrogenHeliumLithiumBeryliumBoronCarbonNitrogenOxygenFluorineNeonSodiumMagnesiumAluminumSiliconPhosphorusSulphurChlorineArgonPotassiumCalcium

So therefore, all elements have a AHf, of 0

kJ/mole at standard temperature and pressure.

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Related Questions

20 Points!! Which of the following is a synthesis reaction? AgNO3+NaCI--> AgCI+NaNO3
CH4+O2->CO2+H2O SO3+H2O-> H2SO4 Cu+AgNO3 ->Ag+CuNO3

Answers

the third one
synthesis reactions have multiple reactants that synthesize into one product

Sodium metal reacts with chlorine gas to produce crystals of sodium
chloride. Show phases in your equation.

Answers

Answer:

Na(s) + Cl(g) = NaCl(s)

Explanation:

s means solid

g means gas

Metals are solid at room temperature.

Crystals are solids

In fossil comparisons, it helps to know about similar:

living things
questions
incomplete remains

Answers

Answer:

Fossils tell us when organisms lived, as well as provide evidence for the Fossils are the preserved remains or traces of animals, plants, and other organisms from the past. Fossils, by comparing the anatomies of both modern and extinct species, allows scientists to study the skin, hair, and organs of ancient creatures.

Explanation:

How many moles of hydrogen sulfide are contained in a 77.7-8 sample of this gas?
Select one:
o
a. 0.44mol
O b.4.56mol
O c. 38.5mol
O d. 111.8mol
e. 2.28mol

Answers

Answer:

its either C or D my guess is C though because 35.0g of hyddrogen is =1.03 mol

Explanation:

Of the predators in the image, which one is most likely a keystone species?

O pine marten
O mountain lion
O eagle
O wolf

Answers

Answer:

mountian lion

Explanation:

What is an extinct species? *
(10 Points)
O A. a species that blends in easily with its environment
O B. a species that resembles another species
O C. a species that was unable to adapt and died out
O D. a species that is bred for specific characteristics

Answers

Answer: C

Explanation: I got it right.

Which substances are released during cellular respiration?

Use complete sentences to explain how the mass of oxygen is conserved during cellular respiration.

Answers

The formula for cellular respiration is the opposite of photosynthesis in a way of remembering it. Glucose (C6H12O6) + oxygen to break it down makes 2 waste products. 6H2O (water) and 6CO2 (carbon dioxide) The most important product would be ATP that the cells use for energy, but I am assuming you wanted to know about what is released. Example: When you exercise, you breath in more oxygen which breaks down more glucose which makes more ATP. That’s why you feel tired. And you start to breath out more and release more CO2 as a waste product being released. Hope this helped!

A compound X has the following percentage composition 66.7% carbon, 11.1% hydrogen and 22.2% oxygen .Calculate the empirical formula of X.The relative molecular mass of X is 72 calculate the molecular formula​

Answers

Explanation:

c. h. o

66.7%. 11.1%. 22.2%

____. ____. ____

12. 1. 16

1.558. 11.1. 1.39. (divide by the smallest)

1. 8. 1

empirical formula=ch8o

SUMMARY: Write a 3-4 sentence summary about molecules.

Answers

Answer:

molecules definition is that "a molecule is an electrical neutral group of two or more atoms held together by chemical bonds molecules are distinguished from ions by their lack of electrical charge." molecules have a part of many things we touch or come across in a everyday life. se example of theses things are water,nitrogen, glucose, and many other things.a molecule is an atom that forms a chemical bond with another atom.

Explanation:

there

the amount of copper sulphate used in dissolution is​

Answers

Answer:

80 gm/mol

Explanation:

it may be helpful

a molecure that contains 3 iddentical polar bonds to the central atom will be

Answers

ANSWER:

Nonpolar

sorry if I'm wrong

what is the geolgic tike scale based on?​

Answers

Answer: The geologic time scale is the “calendar” for events in Earth history. It subdivides all time into named units of abstract time called—in descending order of duration—eons, eras, periods, epochs, and ages.

Explanation: I learned about it the other day

PLS HELP ME WITH MY ASSIGNMENT WILL MARK BRAINLIEST!

Answers

I believe it would be number 2 Cation +1

Answer:

D. anions ; +1

Explanation:

Alkali metals tend to lose one electron and form ions with a single positive charge. 'alkali metals typically lose 1 eclectron to form anions with a charge of +1".

6. Elements in column (group) 18 (8A) are called the________ and the outermost electrons are found in
the p sublevel. Color these elements a different color and reference this group on the legend.

Answers

Answer:

Noble gases

Explanation:

Noble gases have filled electron shells (group 18=8 electrons) and are all odorless, colorless, monatomic gases with very low chemical reactivity.

4)
On a hot day, your friend brings you some iced tea to cool off. Only, its unsweetened. You add sugar, but it just does not dissolve
fast enough. Which procedure would speed up the dissolving process?
A)
Add the sugar in the dark.
B)
Add larger crystals of sugar, or sugar cubes.
C)
Take the tea up to the top of a close mountain.
D)
• Take out the ice and stir it up outside where it is warmer.

Answers

Answer: D)

• Take out the ice and stir it up outside where it is warmer.

Explanation:

Answer:

thank you! I made it to an 100% on USA test prep...

the answer is: Take out the ice and stir it up outside where it is warmer.

Explanation:

I have a lot of rain last night when I go to bed. Stay safe!

1 point
Which piece of apparatus can only measure a single fixed volume?
А250 cm beaker
B50 cm burette
С100 cm measuring cylinder
D25 cm pipette

Answers

Answer:

50 CM burette

Explanation:

bvffvvhjf

On another planet, the isotopes of titanium have the given natural abundances.
Isotope Abundance
Mass (u)
46Ti
70.600%
45.95263
48Ti
12.900%
47.94795
50Ti
16.500%
49.94479
What is the average atomic mass of titanium on that planet?

Answers

im pretty sure you do the number times the percentage converted to a decimal and then add the sums so (46*0.706)+(48*0.129)+(50*0.165)
32.476+6.192+8.25
=46.918 amu

*i dont trust my calc so pleasee check if the answer is right and also remember to convert a percent to decimal move the decimal back 2 places so like for 12.9% the decimal is gonna be 0.129

hope this helpss ask if you have questions

In genetic engineering

Answers

Answer:

what is the question?

Explanation:

Answer:

A

Explanation:

i just did the question :)

5 pos. 1. An excess of sodium sulfate was added to a 500. mL sample of polluted water. The
mass of lead (II) sulfate that precipitatcd was 308.88 mg. Determine the mass of lead that was in
the polluted water.
Na2SO4(aq) + Pb2+ (aq) → 2Na(aq) + PbSO4(s)

Answers

Answer:

[tex]m_{Pb^{2+}}=0.211gPb^{2+}[/tex]

Explanation:

Hello!

In this case, according to the stoichiometry of the reaction, it is possible to evidence the 1:1 mole ratio between lead (II) ions and lead (II) sulfate precipitate; that is why we can compute the mass of lead (II) in the polluted water as shown below:

[tex]m_{Pb^{2+}}=308.88mgPbSO4*\frac{1gPbSO4}{1000mgPbSO4} *\frac{207.2gPb^{2+}}{303.26gPbSO4} \\\\m_{Pb^{2+}}=0.211gPb^{2+}[/tex]

Best regards!

where do coal,oil and natural gas came from?​

Answers

Answer:

I hope it will help you

plz mark me as brainliest

plz thank my answer

Which half reaction is associated with the anode?
Sn(s) —> Sn2+ (aq) + 2e-
Sn2+ (aq) + 2e- → Sn(s)
Pb2+ (aq) + 2e-->Pb(s)
Pb(s)->Pb2+ (aq) + 2e-

Answers

Answer:

vgf

Explanation:

Answer:

its either A or B

Explanation:

took the test twice and guessed LOL
its not C or D :>

1. What is an ionic bond?

Answers

Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion.

Explanation:

ionic bond is a bonding between a non-metal and a metal, that occurs when change atoms (ions) attract.

PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP

DUE IN 5 MINUTES CHEMISTRY DIMENSIONAL ANALYSIS

In 2009, Usain Bolt ran 100 meters in 9.58 seconds. What is this speed in km/hr? (!! DIMENSIONAL ANALYSIS!! NOT A REGULAR PROBLEM)

Answers

100 m = 0.1 km
9.58 sec = 9.58/3600 = 0.00266 hr
Speed = 0.1/0.00266= 37.6 km/hr
Can you mark it brainliest?

how many moles are in 1.505x10^24 molecules of surcrose

Answers

Answer:

2.499 moles of sucrose

Explanation:

Divide by Avogadro's number

Beryllium oxide, Beo, is an electrical insulator. How
many moles of beryllium oxide qre in a 250 gram
sample of the compound?

Answers

Answer:

There are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.

Explanation:

We can calculate the number of moles (η) of BeO as follows:

[tex] \eta = \frac{m}{M} [/tex]

Where:

m: is the mass = 250 g

M: is the molar mass = 25.0116 g/mol

Hence, the number of moles is:

[tex] \eta = \frac{250 g}{25.0116 g/mol} = 10.0 moles [/tex]

Therefore, there are 10.0 moles of beryllium oxide in a 250 grams sample of the compound.  

I hope it helps you!

Help please !!!!!!! 10 points for this

Answers

i think it’s increase, then decrease- sorry if i’m wrong

QUESTION 7 Can you use alligation for any type of liquid? ​

Answers

Answer:

Yes you can use alligation for a type of liquid. Explanation: Alligation is an old and practical method of solving arithmetic problems related to mixtures of ingredients.

Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Thus, we can use allegation for any type of liquid.

What is matter?

Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.

Matter is anything that is made up of atoms. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.

Mass can also be represented as number of molecules. We also saw that matter occupy some volume and that volume is measured only in liter. Allegation is a form of liquid that we may utilize. Allegation is a time-tested and useful strategy for tackling mathematical issues involving combinations of elements.

Thus, we can use allegation for any type of liquid.

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Give the coefficient of y in the following expression. 2xz² - 7xy + 4.​

Answers

Answer:

the coefficient of y is -7

Which of the following can be calculated from the mass of the reactants used in a chemical reaction? (Select all that apply)
Theoretical yield of products
Amount of limiting reactant used in a reaction
Actual yield of products
Amount of excess reactant from a reaction

Answers

Answer:

Can you explain it more please

Explanation:

A boy sets up a picnic on the beach next to a sand dune. How are sand dunes formed?

A. erosion and deposition
B. weathering and erosion
C. tectonic plates
D. precipitation​

Answers

Answer:

B. Weathering and Erosion

Explanation:

I majored in Chemistry

Answer:

b

Explanation:

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