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:
HydrogenHeliumLithiumBeryliumBoronCarbonNitrogenOxygenFluorineNeonSodiumMagnesiumAluminumSiliconPhosphorusSulphurChlorineArgonPotassiumCalciumSo therefore, all elements have a AHf, of 0
kJ/mole at standard temperature and pressure.
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1. What is an ionic bond?
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.
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
Answer:
50 CM burette
Explanation:
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QUESTION 7 Can you use alligation for any type of liquid?
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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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
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
Answer:
Can you explain it more please
Explanation:
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
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
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?
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
Answer:
B. Weathering and Erosion
Explanation:
I majored in Chemistry
Answer:
b
Explanation:
In genetic engineering
Answer:
what is the question?
Explanation:
Answer:
A
Explanation:
i just did the question :)
how many moles are in 1.505x10^24 molecules of surcrose
Answer:
2.499 moles of sucrose
Explanation:
Divide by Avogadro's number
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)
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!
Beryllium oxide, Beo, is an electrical insulator. How
many moles of beryllium oxide qre in a 250 gram
sample of the compound?
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!
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.
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!
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.
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.
the amount of copper sulphate used in dissolution is
Answer:
80 gm/mol
Explanation:
it may be helpful
Help please !!!!!!! 10 points for this
a molecure that contains 3 iddentical polar bonds to the central atom will be
ANSWER:
Nonpolar
sorry if I'm wrong
Of the predators in the image, which one is most likely a keystone species?
O pine marten
O mountain lion
O eagle
O wolf
Answer:
mountian lion
Explanation:
where do coal,oil and natural gas came from?
Answer:
I hope it will help you
plz mark me as brainliest
plz thank my answer
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
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.
Sodium metal reacts with chlorine gas to produce crystals of sodium
chloride. Show phases in your equation.
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
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:
what is the geolgic tike scale based on?
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
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
Answer:
its either C or D my guess is C though because 35.0g of hyddrogen is =1.03 mol
Explanation:
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)
Give the coefficient of y in the following expression. 2xz² - 7xy + 4.
Answer:
the coefficient of y is -7
SUMMARY: Write a 3-4 sentence summary about molecules.
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
PLS HELP ME WITH MY ASSIGNMENT WILL MARK BRAINLIEST!
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".
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-
Answer:
vgf
Explanation:
Answer:
its either A or B
Explanation:
took the test twice and guessed LOL
its not C or D :>