Answer:
-694.8 kJ/mol ≅ -695 kJ
Explanation:
The enthalpy of combustion (ΔHc) is defined as the amount of heat that is released when 1 mol of the compound is burned. We have the mass of methanol (0.14 g) and we have to calculate the moles present in that mass. For that, we need the molecular weight of methanol, which is calculated from the molar mass of the chemical elements.
Methanol: CH₃OH
Mw(CH₃OH) = (12 g/mol x 1 C) + (1 g/mol x 3 H) + 16 g/mol O + 1 g/mol H = 32 g/mol
moles of CH₃OH = mass/Mw(CH₃OH) = 0.14 g/(32 g/mol) = 4.4 x 10⁻³ mol
As the heat is released, the change in enthalpy is a negative value: -3.04 kJ.
Finally, we divide the released heat (-3.04 kJ) into the number of moles of CH₃OH:
ΔHc= (-3.04 kJ)/(4.4 x 10⁻³ mol CH₃OH) = -694.8 kJ/mol ≅ -695 kJ
which location on the map above marks the Weddell Sea?(Giving brainlist for correct answer)
-A
-B
-C
-D
Answer and Explanation:
D. I think..
A plastic bin is found to hold 3.1x10^24 molecules of water.
Calculate the number of moles in the container.
Answer:
[tex]\boxed {\boxed {\sf 5.1 \ mol \ H_2O}}[/tex]
Explanation:
To convert from representative particles to moles, Avogadro's Number: 6.02*10²³, which tells us the number of particles (atoms, molecules, etc.) in 1 mole of a substance.
We can use it in a ratio.
[tex]\frac {6.02*10^{23} \ molecules \ H_2O}{1 \ mol \ H_2O}[/tex]
Multiply by the given number of molecules.
[tex]3.1*10^{24} \ molecules \ H_2O*\frac {6.02*10^{23} \ molecules \ H_2O}{1 \ mol \ H_2O}[/tex]
Flip the ratio so the molecules of water cancel out.
[tex]3.1*10^{24} \ molecules \ H_2O*\frac {1 \ mol \ H_2O}{6.02*10^{23} \ molecules \ H_2O}[/tex]
[tex]3.1*10^{24} *\frac {1 \ mol \ H_2O}{6.02*10^{23} }[/tex]
[tex]\frac {3.1*10^{24} \ mol \ H_2O}{6.02*10^{23} }[/tex]
Divide.
[tex]5.14950166113 \ mol \ H_2O[/tex]
The original number of molecules has 2 significant figures: 3 and 1, so our answer must have the same. For the number we calculated, that is the tenth place. The 4 in the hundredth place tells us to leave the 1.
[tex]5.1 \ mol \ H_2O[/tex]
There are about 5.1 moles of water in 3.1*10²⁴ molecules of water.
PLS HELP DUE IN ONE HOUR The atomic size of atoms increases as you move from top to bottom within a group of
the periodic table. Please explain why the size increases. Limit your response to one
sentence. Use your own words to answer.
Answer:
Within a group trend
Explanation:
The atomic radius of atoms generally increases from top to bottom within a group trend. As the atomic number increases down a group, there is again an increase in the positive nuclear charge. As the atomic number increases within a period, the atomic radius decreases.
in terms of ionic charge explain why the ratio of ions is 3:2
1 How many different elements (types of atoms) are in this molecule C14H9Cl5?
when is an electric charges neutral ??
Answer:
Atoms of matter are electrically neutral because their nuclei contain the same number of protons as there are electrons surrounding the nuclei. Electric current and charged objects involve the separation of some of the negative charge of neutral atoms.
In sweet pea plants, the allele for purple flowers is dominant over the allele for white flowers. If half of the plants in one generation of sweet pea plants has purple flowers, what were the most likely genotypes of the parents?
Explanation:
The genotype for parent is going to be purple flower.
After the crossing is done, we have our p1 to be a purple flower dominant over the the yellow that is to say the parent genotype is going to be a Purple denote a capital P
I NEED THIS URGENT PLZ
Which property of aluminium makes it useful in the manufacture of aircraft?
A conducts electricity
B high boiling point
с low density
D silver colour
Answer:
C
Explanation:
I would say C Low Density
SORRY IF I AM WRONG
HOPE IT HELPS :D
list the five groups in the periodic table
Answer:
I think these are the 5 periodic tables.
75 mL of water is measured in a graduated cylinder. The mass of the water should be
A.
more than 75 grams
B.
less than 75 grams
C.
there is no good way to tell
D.
75 grams
Answer:
D-75 grams
Explanation:
that is the answer
What do you think is the primary reason why the Unionid mussel population declined whenever there is a dramatic increase in the Zebra mussel population?
Answer:
When the Zebra arrived they ate all the food so the Unionid mussels declined as they died from the lack of food. Causing the Zebra Zebra numbers to increase and Unionid numbers to decline.
1. organisms of different species that share similar characteristics most likely have..
2. some members of a species are able to withstand very hot weather conditions due to..
Answer:
1. Parents from both species.
2. Because of natural selection.
Explanation:
HELP! WILL MARK BRAINLEST 12 PTSOrganize: Use the graphic organizer below to organize three factors that increase the speed a solute dissolves in a liquid.
Answer:
i cant see the pic fully
Explanation:
Answer:
Increasing surface area/making particles smaller (like breaking a sugar cube into smaller pieces so that it covers more area), mixing , increasing temperature.
The electromagnetic spectrum includes the complete range of electromagnetic waves placed in order of...
Answer: increasing frequency or energy and decreasing wavelength.
Explanation:
Electromagnetic wave is defined as the wave which is associated with both electrical and magnetic component associated with them. They can travel in vacuum as well and travel with the speed of light i.e
The electromagnetic spectra consist of radio waves, microwaves, infrared ,Visible , ultraviolet, X rays and gamma rays arranged in order of increasing frequency or increasing energy and decreasing wavelengths.
A substance X has a melting point of 649 C a boiling point of 1107 C and id insoluble in water. State an additional test that could b done to find out whether substance X is an ionic compound
Answer:
Electrical Conductivity of the substance
Explanation:
Ionic substances do not conduct electricity in their solid state however they are good conductor of electricity when dissolved in water or in their molten state.
A test can be carried out to see if the substance matches the property above.
- What is the concentration of hydrogen ions if the pH is 12?
Answer:
1 x 10^-12 mol dm^-3
Explanation:
[H+] = 10 ^ -pH
Therefore, pH 12 = 1 x 10^-12 hydrogen ion concentration
Explain how to count the number of elements in a compound
Answer:
The molecular formula lists the symbol of each element within the compound followed by a number (usually in subscript). The letter and number indicate how many of each type of element are in the compound. If there is only one atom of a particular element, then no number is written after the element.
_____ is an example of a heterogeneous mixture.
A)
Tea
B)
Salad
0
Salt
D)
Mayonnaise
B) Salad
heterogeneous mixtures have a non-uniform composition with components in at least two different phases
Which objects should not be thrown in landfills because they could leach into groundwater and pollute the water?
A. paints
B. aluminum foil
C. plastics
D. paper
what is a hydrocarbon
Answer:
A hydrocarbon is any of a class of organic chemicals made up of only the elements carbon (C) and hydrogen (H).
Explanation:
Exam
How many miles are there in
12,327 feet?
Answer:
2.3346591
or round to 2.3
Answer:
2.335 miles
Explanation:
2.335 miles is in 12,327 feet.
how many liters are in 1.5 moles of h2 ?
Answer:
34.35 liters
Explanation:
After setting up the formula using the mole map, you would get 1.5 (mol) times 22.4 (liters)
CaSO4 +
Al(NO3)3
+
Al; (507)
Ca(NO3)2
Answer:
what are you looking for?
Explanation:
A battery lighting a bulb is an example of ____energy converting to____energy.
magnetic
electrical
chemical
gravitational
heat
nuclear
kinetic
What is the mass in grams of 5.67 x 1021 molecules of carbon dioxide?
Answer:
5789.07
Explanation:
Identify the acid, base, conjugate acid, and conjugate base in the following reaction.
HNO3 + NH3 + NO3 + NH
HNO3
NH3
NO3
NHA!
Base
Acid
Conjugate acid
Conjugate base
Please answer ignore the answers below in the pic they are wrong
when and if element 119 is discovered predict where it would be placed on the modern periodic table
Answer:yes
Explanation:
Because modern periodic table is designed in such a way that it can accomodate any new elemet which may be discovered in future
We have that for the Question "when and if element 119 is discovered predict where it would be placed on the modern periodic table" it can be said that With the existing information the element 119 will most likely be i the 8th period and the first group of the periodic table
8th period and the first group of the periodic tableFrom the question we are told
when and if element 119 is discovered predict where it would be placed on the modern periodic table
Generally
The Periodic table is naturally designed to accommodate new elements based on there properties
Therefore
With the existing information the element 119 will most likely be i the 8th period and the first group of the periodic table
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plant cells are the only type of cell with a cell wall
true
false
?
Answer:
true
Explanation:
All cells have a cell wall. Plant cells are surrounded by a cell membrane and outside this is a fairly rigid cell wall. The cell wall gives the plant cell a more definite shape than an animal cell. Animal cells do not have a cell wall.
Answer:
True
Explanation:
Animal cells don't have any cell walls while plants do
Please choose the correct sequence that describes the excitement of an atom.
Such an electron transition raises the atom from the ground state to the excited state.
When energy is added to an atom from an outside source, its electrons move to a higher energy level (orbit)
As a result, the atom emits a photon.
When the atom is in an excited state, the electron can drop from the higher energy level to a lower energy level.
A) 2, 1, 4, 3
B) 4, 3, 2, 1
C) 3, 4, 1, 2
D) 1, 2, 3, 4
As Earth orbits the Sun, the seasons slowly change from one to the other. 5 points
Which of the following statements explains the occurrence of summer in
the Northern Hemisphere?
Earth is closest to the Sun in summer.
The Northern Hemisphere is tilted toward the Sun in summer.
The Northern Hemisphere is tilted away from the Sun in summer.
All parts of Earth receive more sunlight in summer.
Answer:
The Northern Hemisphere is tilted toward the Sun in summer is the correct answer.I hope this helps
Explanation:
Day turns into darkness as the Earth spins, and summer turns into winter when the Earth completes its whole cycle. Therefore, the Northern Hemisphere is tilted toward the Sun in summer. The correct option is option B.
What is rotation?The circular motion of an item about its center is referred to as rotation. Things can spin in a variety of ways. When a round, three-dimensional object rotates around an imaginary line inside of its center, it is a relatively common type of rotation. This focal point is known as an axis.
The Earth's rotation and revolution effect wind patterns, temperature, ocean currents, and precipitation, which together determine our local weather and the planet's overall climate. the Northern Hemisphere is tilted toward the Sun in summer.
Therefore, the Northern Hemisphere is tilted toward the Sun in summer. The correct option is option B.
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