A cooling curve has two flat lines, or plateaus. The plateau at the higher temperature represents condensation of a gas and the correct option is option C.
What is Cooling curve?
When a solid substance is heated until it is completely melted, and then heated further and allowed to cool slowly, the curve obtained by plotting temperature against time is known as the cooling curve.
The gradient of the cooling curve is related to the heat capacity, the thermal conductivity of the substance, and the external temperature. The more heat is required to change the temperature of the substance, the slower it cools, so the smaller the gradient of the curve. The higher the thermal conductivity, the faster heat is transferred, so the faster the substance cools.
Therefore, A cooling curve has two flat lines, or plateaus. The plateau at the higher temperature represents condensation of a gas and the correct option is option C.
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Suppose of nickel(II) bromide is dissolved in of a aqueous solution of potassium carbonate. Calculate the final molarity of nickel(II) cation in the solution. You can assume the volume of the solution doesn't change when the nickel(II) bromide is dissolved in it. Round your answer to significant digits.
The question is incomplete, the complete question is;
Suppose 1.87g of nickel(II) bromide is dissolved in 200.mL of a 52.0mM aqueous solution of potassium carbonate. Calculate the final molarity of nickel(II) cation in the solution. You can assume the volume of the solution doesn't change when the nickel(II) bromide is dissolved in it. Be sure your answer has the correct number of significant digits. The answer is needed in M.
Answer:
0.0428 M
Explanation:
The equation of the reaction is;
NiBr2 + K2CO3 → NiCO3 + 2KBr
Number of moles of NiBr2 = mass/molar mass = 1.87 g/218.53 g/mol =
8.557 * 10^-3 moles
Now, we know that the Ni^2+ comes from the NiBr2. Also, the concentration of Ni^2+ in NiBr2 = concentration of Ni^2+ in NiCO3
So,
Concentration of Ni^2+ = 8.557 * 10^-3 moles/0.2 L = 0.0428 M
What can scientists do or use to predict when and where natural hazards could occur?
Answer:
Earth Scientists Use Fractals To Measure And Predict Natural Disasters.
Explanation:
Answer:they can use fractals
Explanation:
Each of the following organs had a role in excretion, EXCEPT for the _____?
A. Lungs
B. Kidneys
C. Heart
D. Skin
Each of the following organs had a role in excretion, except for the Heart. Therefore, the correct option is option C.
What is excretion?Excretion seems to be the process throughout which an organism eliminates metabolic waste. In vertebrates, this is largely done by that of the skin, kidneys, especially lungs. When a substance is secreted, this could perform certain roles once it leaves the cell. Excretion is required by all forms of life.
Animals, for example, use the urethra, a member of the excretory, to evacuate urine. In unicellular organisms, waste products are ejected quickly via the cell surface. During biological functions, such as cellular respiration, a variety of chemical changes occur in the body. Each of the following organs had a role in excretion, except for the Heart.
Therefore, the correct option is option C.
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Give the formula of the alkanes his molecule contains 28 hydrogen atoms
Answer:
jayfeather friend me
Explanation:
Table 1. Summary of the Straight-Chain Alkanes
Name Formula Number of Structural Isomers
Octadecane C18H38
Nonadecane C19H40
Eicosane C20H42 366,319 (!)
29 more rows
The formula of the alkanes the molecule contains 28 hydrogen atoms is [tex]C_1_3H_2_8[/tex], i.e., tridecane.
What are alkanes?Alkanes are organic compounds made up entirely of single-bonded carbon and hydrogen atoms with no other functional groups.
Alkanes have the general formula CnH2n+2 and are classified into three types: linear straight-chain alkanes, branched alkanes, and cycloalkanes.
Alkanes are important raw materials in the chemical industry and the main component of gasoline and lubricants.
Natural gas is primarily composed of methane and ethane and is used for heating, cooking, and power generation (gas turbines).
Natural gas and petroleum are separated from the alkanes. Natural gas is primarily composed of methane, with trace amounts of other low molecular weight alkanes.
All other alkanes are derived from petroleum, which is a complex mixture of many compounds.
Here, the formula for 28 hydrogen atom containing alkane is
[tex]C_1_3H_2_8[/tex]
Thus, this given formula is of tridecane.
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What is the mass in grams of 2.5 mol of O2?
Answer:
80grams
Explanation:
RAM of O=16
molar mass of O2= 16×2=32g/mol
mass= mole × molar mass
= 2.5×32= 80g
Which of these substances would be an alkali?
A substance which turns universal indicator orangeA substance with a pH of 1A substance which turns universal indicator blueA substance with a pH of 7
Label one of the test tubes Fe2+. Add 4 milliliters of iron(II) sulfate to the test tube.
Label the other test tube Fe3+. Add 4 milliliters of iron(III) nitrate to the test tube.
Add 4 milliliters of potassium thiocyanate to each test tube.
Observe the contents of the test tubes, noting any evidence of a chemical reaction. Record your observations in the table. If there is no evidence of a reaction, write “no reaction.”
Answer: A: Has little to no reaction; might turn slightly red in color. B: The liquid grows darker in color to a more reddish tone.
Explanation: I didn’t have the necessary materials to complete the experiment so the teacher told me and I put it in my own words.
Please Help! (Chemistry Molecules to Grams)
Answer:
20.95 g of caffeine, C₈H₁₀N₄O₂
Explanation:
From the question given above, the following data were obtained:
Number of molecules of C₈H₁₀N₄O₂ = 6.5×10²² molecules
Mass of C₈H₁₀N₄O₂ =?
From Avogadro's hypothesis,
1 mole of C₈H₁₀N₄O₂ = 6.02×10²³ molecules
Next, we shall determine the mass of 1 mole of C₈H₁₀N₄O₂. This can be obtained as follow:
1 mole of C₈H₁₀N₄O₂ = (8×12) + (10×1) + (4×14) + (2×16)
= 96 + 10 + 56 + 32
1 mole of C₈H₁₀N₄O₂ = 194 g
Thus,
194 g of C₈H₁₀N₄O₂ = 6.02×10²³ molecules
Finally, we shall determine the mass of caffeine, C₈H₁₀N₄O₂ that contains 6.5×10²² molecules. This can be obtained as follow:
6.02×10²³ molecules = 194 g of C₈H₁₀N₄O₂
Therefore,
6.5×10²² molecules = (6.5×10²² × 194) / 6.02×10²³
6.5×10²² molecules = 20.95 g of C₈H₁₀N₄O₂.
Therefore, 20.95 g of caffeine, C₈H₁₀N₄O₂ contains 6.5×10²² molecules
Menstruation occurs on a ______ interval from puberty until menopause
A. Three months
B. Two months
C. Half month
D. One month
I'll give brainliest to whoever gives me the answer to all of this.
After looking at the schematics of the bubble, he finds that it holds 0.750 moles of gas at Standard Temperature and Pressure. Unfortunately for Rooster, helium gas is not sold by the mole, only by the liter. He needs to know how many liters of gas 0.750 moles of helium is.
Answer:
16.8 L
Explanation:
From the question given above, the following data were obtained:
Number of mole of He = 0.750 mole
Volume of He =?
Recall:
1 mole of any gas occupy 22.4 L at STP. This also implies that 1 mole of He occupies 22.4 L at STP.
Finally, we shall determine the volume occupied by 0.750 mole of He. This can be obtained as follow:
1 mole of He occupied 22.4 L at STP.
Therefore, 0.750 mole of He will occupy = 0.750 × 22.4 = 16.8 L at STP.
Thus, 0.750 mole of He is equivalent to 16.8 L
What does the symbol (s) represent when it is next to an atom?
Answer:
The symbol for an atom indicates the element via its usual two letter symbol, the mass number as a left superscript, the atomic number as a left subscript (sometimes omitted), and the charge as a right superscript.
Explanation:
I hope that helps!! sorry if it dont!
2. Methyl dichloroacetate (Cl2CHCO2CH3) decays into methanol (CH3OH) and dichloroacetic acid (Cl2CHCO2H) on reaction with water. Given a rate constant of 2.7 x 10-4/sec and an initial concentration of 1-ppm methyl dichloroacetate in the water, how much methanol will be present in the water after 30 min
Answer:
2.69 * 10^-6 Mol/L
Explanation:
The equation of the reaction is;
Cl2CHCO2CH3 -------------------> Cl2CHCO2H + CH3OH
To convert from ppm concentration to Mol/L, we have
M = ppm/MM * 1000
Where;
M = mol/l
MM= Molar mass
M = 1/142.97 g/mol * 1000 =
M= 6.99 * 10^-6 Mol/L
For first order reaction;
ln[A] = ln[A]o -kt
Given that
[A]o = 6.99 * 10^-6 Mol/L
[A]=??
k= 2.7 x 10-4/sec
t= 30 mins * 60 = 1800 s
ln[A] = ln[6.99 * 10^-6] - (2.7 x 10-4 * 1800)
ln[A] = -11.87 - 0.486
ln[A] = -12.356
[A] = e^(-12.356)
[A] = 4.3 * 10^-6 Mol/L
Concentration of methanol present after 30 mins= 6.99 * 10^-6 - 4.3 * 10^-6 = 2.69 * 10^-6 Mol/L
The density of copper is listed as 8.94 g/mL. Two students each make three density determinations through experimentation. Student A's measurements are 6.3 g/mL, 8.9 g/mL, and 11.1 g/mL. Student B's measurements are 8.3 g/mL, 8.2 g/mL, and 8.4 g/mL. Compare the two sets of results in terms of precision and accuracy.
Answer:A) After the values are added, we determine how many significant figures are involved by looking at the decimal places of the original values. 52.13 had only 2 digits past the decimal point so the answer can only contain 2 significant numbers after the decimal point which would be 53.88 g
Explanation:
It’s a test and only need 2 more problems!!!! Thank you and Appreciate it!!!
Answer:
the molar mass of propane (c3H8) is
12*3+1*8
=36+8=44
what is the substance? cdH) (Η) (Η
(H)C
cco
Ή) (Η
Η
Η
Answer:
A substance is a pure single form of matter. It cannot be separated into other kinds of matter by any physical process.
To measure the amount of nickel in some industrial waste fluid, an analytical chemist adds sodium hydroxide solution to a sample of the fluid and collects the solid nickel(II) hydroxide product. When no more is produced, he filters, washes and weighs it, and finds that has been produced. The balanced chemical equation for the reaction is:
Answer:
The final balanced equation is
Ni2+ + 2NaOH --> Ni (OH)2 + 2Na+
Explanation:
It is given that sodium hydroxide is added to collect the solid nickel(II) hydroxide product
The empirical equation for this statement is
Ni2+ + NaOH --> Ni (OH)2 + Na+
We will first balance the hydroxide molecule. On the right side there are two OH molecules.
Thus, on the left side we will take 2 sodium hydroxide
Ni2+ + 2NaOH --> Ni (OH)2 + Na+
Now we will balance the sodium ion which are 2 in numbers on the left side and 1 on the right side
Ni2+ + 2NaOH --> Ni (OH)2 + 2Na+
So, the final balanced equation is
Ni2+ + 2NaOH --> Ni (OH)2 + 2Na+
One mole of a metallic oxide reacts with one mole of hydrogen to produce two moles of the pure metal
and one mole of water. 5.00 g of the metallic oxide produces 2.32 g of the metal. What is the metallic
oxide?
Answer:
Lithium oxide, Li₂O.
Explanation:
Hello!
In this case, according to the given amounts, it is possible to write down the chemical reaction as shown below:
[tex]M_2O+H_2 \rightarrow 2M+H_2O[/tex]
Which means that the metallic oxide has the following formula: M₂O. Next, we can set up the following proportional factors according to the chemical reaction:
[tex]5.00gM_2O*\frac{1molM_2O}{(2x+16)gM_2O}*\frac{2molM}{1molM_2O}*\frac{xgM}{1molM} = 2.32gM[/tex]
Thus, we perform the operations in order to obtain:
[tex]\frac{10x}{2x+16}=2.32[/tex]
So we solve for x as shown below:
[tex]10x = 2.32(2x+16)\\\\10x = 4.64x+37.12\\\\x = \frac{37.12}{10-4.64}\\\\x= 6.93 g/mol[/tex]
Whose molar mass corresponds to lithium, and therefore, the metallic oxide is lithium oxide, Li₂O.
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15 The picture shows Earth’s rotation. Which pattern listed below is caused by Earth’s rotation? A Water cycle processes B Length of shadows C Seasonal temperatures D Weathering and erosion HELP ME
Answer:
jayfeather friend me
Explanation:
Hence it is quite important to understand and learn the processes of the water cycle.
Step 1: Evaporation. The water cycle starts with evaporation. ...
Step 2: Condensation. ...
Step 3: Sublimation. ...
Step 4: Precipitation. ...
Step 5: Transpiration. ...
Step 6: Runoff. ...
Step 7: Infiltration.
Define
wheel and axel
Answer:
A wheel and axle is a simple lifting machine that consists if rope that unwind a wheel onto a cylindrical drum/ shaft to provide mechanical advantage.
wheel and axle is a simple machine having two co-axial cylinder of different radii fitted to a common axies.
Is the study of matter and energy complete, or do you think there’s still new information to discover?
Answer:
Physical science, in turn, can be divided into chemistry and physics. Chemistry is the study of matter and energy at the scale of atoms and molecules. ... Physics is the study of matter and energy at all scales—from the tiniest particles of matter to the entire universe but i dont really know if there is new information to discover
Explanation:
hope it help and if it doesnt sorry ;)
When going down a slope on a roller
coaster, does your stomach actually
move up?
Answer:
yes
Explanation:
due to gravity &hggggggggg%ggghhbvvvghh
Fill in the coefficient needed to make the equation balanced.
1. _______ Na + Cl2 → ______NaCl
a. 2, 2
b. 2, 3
c. 2, 1
d. 2, 4
2. _______Al + _______S → Al2S3
a. 2, 2
b. 2, 3
c. 2, 4
d. 2, 6
3. ______ H2 + O2 → ______H2O
A. 2, 2
b. 2, 3
c. 2, 4
d. 2, 8
4. _______Fe + ______O2 → ______Fe2O3
a. 4, 2, 2
b. 4, 2, 1
c. 4, 3, 2
d. 4, 3, 1
Answer:
1 a
2 b
3 a
4. c
Explanation:
6. Describe nuclear fusion reactions as they
occur in the sun.
Answer:
i wish i know
Explanation:
i wish i know
There are many important laws and theories in science. Which of the following is a law of science?
A living thing is made of at least one cell.
ОО
An atom is made of electrons orbiting a nucleus.
Gravity will pull two objects toward each other.
Natural selection will change species to fit their environments.
Answer: the answer is C
Explanation:
Answer:C
Explanation:I got it correct
Which types of energy transformations does a television make?
Electrical energy to energy of motion and heat energy
Electrical energy to heat energy and light energy
Electrical energy to sound energy and energy of motion
Electrical energy to sound energy and light energy
Answer:
d.
Explanation:
the electricity is why we can hear sounds from the television and see it
1. What is the molar mass of Al2S3?
Answer:
150.17 g/mol
Explanation:
235U92 + 1N0 + 135Cs55 + 99Rb37 + x1n0
Which individual elements make up the following common
compounds?
CaCO 3
CaCl 2
C H O 3 6
HCl
Ca(OH) 2
Answer:
I think it will carbon hope it helps
Lithium diorganocopper (Gilman) reagents are prepared by treatment of an organolithium compound with copper(I) iodide. Decide what lithium diorganocopper (Gilman) reagent is needed to convert 1-bromopropane into propylcyclohexane. Draw the structure of the organolithium compound that is used to prepare Gilman.
Answer:
See explanation and image attached
Explanation:
The Gilman reagent is a lithium and copper (diorganocopper) reagent with a general formula R2CuLi. R is an alkyl or aryl group.
They are useful in the synthesis of alkanes because they react with organic halides to replace the halide group with an R group.
In this particular instance, we intend to synthesize propylcyclohexane. The structure of the lithium diorganocopper (Gilman) reagent required is shown in the image attached to this answer.