Answer:
200.6cm³
Explanation:
Using Charles law equation as follows:
V1/T1 = V2/T2
Where;
V1 = initial volume (cm³)
V2 = final volume (cm³)
T1 = initial temperature (K)
T2 = final temperature (K)
According to the question;
initial volume (V1) = 254cm³
final volume (V2) = ?
Initial temperature (T1) = 72.6°C = 72.6 + 273 = 345.6K
Final temperature (T2) = 273K
V1/T1 = V2/T2
254/345.6 = V2/273
Cross multiply
345.6 × V2 = 273 × 254
345.6V2 = 69342
V2 = 69342 ÷ 345.6
V2 = 200.6cm³
HELP PLEASE I BEG YOU
guys please help me i've been struggling with this question all school day (what reaction is ___ Mg + ____ H₂SO₄ --> ____ H₂ + ____ MgSO₄ )
Answer:
Single replacement reaction
Explanation:
It's already balanced so it would just be Mg + H2SO4 --> H2 + MgSO4
The formula for a single replacement reaction is
A + BC --> B + AC
A=Mg
B=H2
C=SO4
NEED HELP ASAP!!! 20 POINTS!!
Which of the following is an exothermic reaction?
A) N2(g) + 2O2(g) → 2NO2(g) ∆H = +66.4 kJ
B) 2C(s) + H2(g) +227.4 → C2H2(g)
C) 4Al(s) + 3O2(g) → 2Al2O3(s) + 3351 kJ
D) N2(g) + O2(g) → 2NO(g) ∆H = +182.6
Answer:
exo means energy is released when delta h is + it is endo and when energy is on the reactants side that is energy introduced so endo as well so when energy shows up on the product side that is the exo one
so it is C as that E is listed as a product therefore released
Explanation:
Which of the following masses is the greatest?
Answer:
4.2 gigagrams
Explanation:
kilo = 1,000
giga = 1,000,000,000
milli = .001
The chemical analysis of a compound gave the percentage composition by mass: Carbon 40%, Hydrogen 6.67% and Oxygen 53.3%. The relative formula mass of a compound is 180. What is the molecular formula of this compound?
Answer:
C6H12O6
Explanation:
I attached the method for solving above.
In the list below, What were the likely ACID and BASE that react to form KCl?
HCl
H2SO4
Ca(OH)2
KOH
NaOH
HBr
Answer:
HCI and KOH
Explanation:
HCI + KOH >> H2O + KCI
Identify the product(s) in the reaction below. 2H20 - 2H2 + O2 O
A. H₂O O
B. H20 and H2 O
C. H20 and 02 O
D. H2 and 02
H2 and 02 are the products of this chemical reaction because of the splitting of water molecule.
What are the products of this reaction?The products of this chemical reaction are H2 and 02 because when the water molecule dissociates or splits hydrogen and oxygen molecules are formed. We know that water is produced from the combination of hydrogen and oxygen.
So we can conclude that H2 and 02 are the products of this chemical reaction because of the splitting of water molecule.
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wuuutttttt....help me
Diamonds are one of the hardest materials known. Hardness is how resistant a material
is to being scratched by another material. If two samples of metal that appear identical
are scratched by a diamond, is that sufficient to determine that they are the same metal?
Why or why not?
Question 3 please help :)
Explanation:
Removing B from the system
- Decreases the rate of the reaction. Backward reaction (formation of reactants) is favoured.
Crushing A into a powder
- Increases the rate of reaction. This is because of the increased surface area of A.
Warming the system
- Increases the rate of the reaction. Temperature is proportional to rate of reaction.
Adding more A to the system
- Increases the rate of reaction. Forward reaction (formation of products) is favoured.
Putting the system into an ice bath
- Decreases the rate of reaction. Temperature is proportional to rate of reaction.
Decreasing the pressure of the system
- Decreases the rate of the reaction.
At what point is a base no longer added during a titration?
A. when the pH increases suddenly in the flask
B. when the phenolphthalein remains clear in the flask
C. before the solution in the flask reaches the equivalency point
D. before half of the base is completely drained from the burette
Answer:
when the pH increases suddenly in the flask
Explanation:
I think it's right. :)
When the pH increases suddenly in the flask at that point is a base no longer added during a titration.
What is titration?Titration is a typical quantitative chemical analysis procedure used in laboratories to quantify the concentration of a specified analyte. The titrant or titrator is a reagent that is produced as a standard solution with a known concentration as well as volume.
What is pH?The pH scale, which originally stood for "potential of hydrogen," is used to describe the acidity as well as basicity of aqueous solutions. The pH of acidic solutions is lower than that of basic as well as alkaline solutions.
To know more about pH and titration.
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 For each phenotype, write the possible genotypes.
In pea plants, tall is dominant over short.
A.Tall: _______,_____
B. Short :________
Answer:
Tall, Res, Dom
short, RES, RES
How many Molecules of oxygen are produced by the reaction of 7.89 grams of KCIO3
KCIO3 — KCI + O2
Answer:
5.81×10²² molecules of oxygen.
Explanation:
This a reaction of decomposition:
2KClO₃ → 2KCl + 3O₂
2 moles of potassium chlorate can produce 2 moles of potassium chloride and 3 moles of oxygen.
We determine the amount of salt.
7.89 g. 1mol /122.55g = 0.0644 moles.
If 2 moles of salt, can produce 3 moles of oxygen.
0.0644 moles of salt may produce (0.0644 . 3) /2 = 0.0966 moles.
Let's count the molecules.
1 mol oxygen contains 6.02×10²³ molecules
Then, 0.0966 moles may contain (0.0966 . NA) = 5.81×10²² molecules
which factor prompts flowering in most plants?
4. Calculate the mass of each element:
a) 3.25 mol of He
b) 0.0455 mol of Ni
c) 1.33 mol of K
_Al + _Fe(NO3)2 -->_Fe + __Al(NO3)3
A sample of gas consists of 4.0 moles, and exists at stp. What is the volume of the gas?
Answer:
The volume of the gas is 89.60
Explanation:
When converting from moles to volume, you would multiply by 22.4 because 1 mole equals 22.4 liters at STP.
So...
4.0 moles * 22.4 liters =
89.60 liters
Answer:
[tex]\boxed {\boxed {\sf 89.6 \ liters}}[/tex]
Explanation:
At STP (standard temperature and pressure), all gases have a volume of 22.4 liters per mole.
[tex]\frac {22.4 \ L }{1 \ mol }[/tex]
Multiply by the given number of moles, 4.0
[tex]4.0 \ mol *\frac {22.4 \ L }{1 \ mol }[/tex]
The moles will cancel out. The 1 in the denominator can be ignored, so this becomes a simple multiplication problem.
[tex]4.0 * {22.4 \ L }=89.6 \ L[/tex]
4.0 moles of a gas at STP have a volume of 89.6 liters.
Cells can do three kinds of work: making proteins and polymers, transporting substances, and
A)
PΔV work to move a piston.
B)
energy work.
C)
mechanical work, such as contracting muscles.
D)
heat work.
Answer:
The correct answer is - option C. mechanical work, such as contracting muscles.
Explanation:
Cells perform three major work that can be categorized in chemical work, mechanical work, and transport work. Production of the large molecules is an example of chemical work.
The transport work includes transporting substances across the membrane such as moving the ions across a plasma membrane. Contraction of the muscles and the movements of cilia is mechanical work.
c What mass of gas is present in
48 cm of oxygen. O2
Answer:
carbon dioxide
Explanation:
because we breath in oxygen and breath out Carbon
Mg(OH)2 + 2 HBr à MgBr2 + 2 H2O
Answer the questions below based on the above reaction. Answer with the correct number of significant figures. Show your work! Each question is worth 8 points. 1 point for sig figs, 1 point for correct final unit, 3 points for correct final answer, 2 points for correct molar masses, and 1 point for dimensional analysis table.
1. How many grams of MgBr2 will be produced from 18.3 grams of HBr?
2. How many moles of H2O will be produced from 18.3 grams of HBr?
3. How many grams of Mg(OH)2 are needed to completely react with 18.3 grams of HBr?
Explanation:
The balanced equation of the reaction is given as;
Mg(OH)2 (s) + 2 HBr (aq) → MgBr2 (aq) + 2 H2O (l)
1. How many grams of MgBr2 will be produced from 18.3 grams of HBr?
From the reaction;
2 mol of HBr produces 1 mol of MgBr2
Converting to masses using;
Mass = Number of moles * Molar mass
Molar mass of HBr = 80.91 g/mol
Molar mass of MgBr2 = 184.113 g/mol
This means;
(2 * 80.91 = 161.82g) of HBr produces (1 * 184.113 = 184.113g) MgBr2
18.3g would produce x
161.82 = 184.113
18.3 = x
x = (184.113 * 18.3 ) / 161.82 = 20.8 g
2. How many moles of H2O will be produced from 18.3 grams of HBr?
Converting the mass to mol;
Number of moles = Mass / Molar mass = 18.3 / 80.91 = 0.226 mol
From the reaction;
2 mol of HBr produces 2 mol of H2O
0.226 mol would produce x
2 =2
0.226 = x
x = 0.226 * 2 / 2 = 0.226 mol
3. How many grams of Mg(OH)2 are needed to completely react with 18.3 grams of HBr?
From the reaction;
2 mol of HBr reacts with 1 mol of Mg(OH)2
18.3g of HBr = 0.226 mol
2 = 1
0.226 = x
x = 0.226 * 1 /2
x = 0.113 mol
HELPPPP!!!
Which element has the greatest atomic size?
a) Francium
b) Hydrogen
c) Rubidium
d) Sodium
Answer:
A. Francium
Explanation:
I'm not for sure but I believe this is correct. Hope it helps:)
W + BgCz2 --> WCz + Bg
Balance this equation
Answer: W + BgCz2 arrow WCz + Bg
2 W + BgCz2 arrow 2 WCz + Bg
Explanation:
Cz has 2 so you balcne the other side of WCz.
Since you Balcanes the Cz you changed the W and you Balcanes the other W on the left side.
Please help Me I really need it
What is the name for Fe2(CO3)3?
Answer:
thing
Explanation:
always
1. Sam needs to know the volume of a cardboard box. Which tool
would he use to find the measurements he needs to calculate
volume?
A)ruler
B(balance
C) spring scale
D)thermometer
A flask contains helium and nitrogen
gases. The partial pressures of each are
77 mm Hg and 87 mm Hg, respectively.
What is the total pressure in the flask in
mm Hg?
total pressure
=77 mmHg+87 mmHg
=164 mmHg
Answer: 164 mm Hg
Explanation: 7 mmHg+87 mmHg
=164 mmHg
Which of the following sentences about the flow of energy is
correct?
Answer:
option B is correct
Energy flows between the trophic levels of different food chain
hope it helps
Energy flows between the trophic levels of the different food chains. So the correct option is B.
What is the trophic level?The trophic level is a step in a nutritive series also called a food chain which is an integral part of an ecosystem. The organisms that are part of a food chain are classified into these energy levels. This classification is on the basis of their feeding behavior.
The first and the lowest level is designated for producers which are the green plants. These plants or the products produced by these plants are consumed by second-level organisms the herbivores, or plant eaters.
They are called primary consumers. At the third level, there are the primary carnivores, which are the meat eaters. These organisms feed on herbivores. They are called secondary consumers. At the fourth level, secondary carnivores are eaten by the primary carnivores.
These categories of levels are not rigid in their definition, as there are many organisms that feed on several trophic levels. For example, some carnivores also feed on plant materials or carrion and are called omnivores, and some herbivores can occasionally eat animal matter.
There is a separate trophic level for the decomposers or the transformers which consist of organisms like bacteria and fungi. These break down dead organisms and waste materials into nutrients usable by the producers.
Therefore the correct option is B.
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Number 2 plssssssssssssssssssssssssssssssss
Answer:
Its located on North America
Miscible liquids that have different boiling points can be separated by _______.
A.filtration
B.distillation
C.chromotagraphy
D.evaporation
Please help it's due soon
Please help me!! :DDDDD
Answer:
i think b
Explanation: