Answer:
Writing down background information can help you to remember what you learned and can be used for notes in the future when taking an assessment.
Explanation:
Can I get brainliest? It's for a challenge
Why do scientist conduct experiments on animals?
Answer:
Animals are used in scientific research to help us understand our own bodies and how they work. This is necessary to develop new medicines. Animals are also used to safety test potential medicines before they are tested in people and to check the safety of other chemicals.
Explanation:
When sodium chloride is dissolved in water, the freezing point of water _________. A. increases B. first increases, then decreases C. does not change D. decreases
The presence of a non-volatile salt will decrease the freezing point of water and this process is called depression in freezing point. Thus option D is correct.
What is freezing point?Freezing point of a substance is the temperature at which it converts from its liquid state to solid state where, both the states are in equilibrium. Freezing point of water is zero degree celsius.
The freezing point of a solvent depends on some parameters such as the bond type, molecular weight, temperature, pressure etc.
When a non-volatile solute is added to the solvent its freezing point decreases from its initial value. Because presence of non-volatile salts will affect the intermolecular attraction and thereby the energy that must be applied to freeze the compound.
Therefore, the freezing point of water decreases, when sodium chloride is added into it. Thus option D is correct.
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How many grams of ethanol, C2H5OH, can be boiled with 843.2 kJ of heat energy? The molar heat of vaporization of ethanol is 38.6 kJ/mol.
Answer:
1.00 × 10³ g
Explanation:
Step 1: Given data
Provided heat (Q): 843.2 kJMolar heat of vaporization of ethanol (ΔH°vap): 38.6 kJ/molStep 2: Calculate the moles of ethanol vaporized
Vaporization is the passage of a substance from liquid to gas. We can calculate the number of moles (n) vaporized using the following expression.
Q = ΔH°vap × n
n = Q / ΔH°vap
n = 843.2 kJ / (38.6 kJ/mol) = 21.8 mol
Step 3: Calculate the mass corresponding to 21.8 moles of ethanol
The molar mass of ethanol is 46.07 g/mol.
21.8 mol × 46.07 g/mol = 1.00 × 10³ g
The conversion of the liquid into water vapor is called vaporization.
The correct answer to the question is [tex]1.00 * 10^3 g[/tex]
The data given in the question is as follows:-
Provided heat (Q): 843.2 kJ Molar heat of vaporization of ethanol (ΔH°vap): 38.6 kJ/molThe formula we will use to calculate the moles is as:-
[tex]Q = H^ovap* n\\n = \frac{Q}{H^ovap}\\n = \frac{843.2 kJ}{(38.6 kJ/mol)} \\\\= 21.8 mol[/tex]
To calculate the mass of the following is as follows:-
The molar mass of ethanol is 46.07 g/mol.
[tex]21.8 mol* 46.07 g/mol = 1.00 * 10^3 g[/tex]
Hence the correct answer is [tex]1.00 * 10^3 g[/tex].
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Atmospheric pressure decreases as altitude increases. In other words, there is more air pushing down on you at sea level, and there is less air pressure pushing down on you when you are on a mountain.If pentane (C5H12), hexane (C6H14), and hexanol (C6H13OH) are heated evenly at different altitudes.
Required:
Rank them according to the order in which you would expect them to begin boiling.
Answer:
Pentane » Hexane » Hexanol
Explanation:
Pentane and Hexane are simple molecular structured with discrete molecules having weak vanderwaals forces of attraction. But Hexane has high molecular mass than pentane hence pentane has lower boiling point than Hexane.
Hexanol has hydrogen bonds between highly electronegative oxygen atom and the hydrogen atom which break on high heat energy application hence it has high boiling point.
Observe the above circuit diagram, if the gap is filled with a plastic wire, will the bulb glow? Justify your answer
Answer:
YES THE BULB WILL GLOW.
Explanation:
BECAUSE THE CIRCUIT UPPER AREA IS MADE OF PLASTIC SO THE PLASTIC CONDUCTS THE ELECTRICITY SO THE BULB WILL GLOW.
State the number of neutrons in an atom of Ne-20 and the number of neutrons in an atom of Ne-22. choose two answers * 1 point Ne 20: 10 Ne 20: 11 Ne 22: 12 Ne 22: 13
Answer:
Ne 20: 10
and
Ne 22: 12
Explanation:
Ne-20:
N = A - Z = 20 - 10 = 10 neutrons
Ne-22:
N = A - Z = 22 - 10 = 12 neutrons
N: number of neutrons
A: mass number
Z: atomic number
ch3-co-ch2-ch2-ch3 IUpAC name
Answer:
2-pentanone.
Explanation:
Hello there!
In this case, for the given compound and, in agreement with the octet rule, it is possible to realize that the CO is actually C=O as shown below:
CH3 - C - CH2 - CH2 - CH3
||
O
Thus, since the C=O stands for the carbonyl group within the parent chain, we infer this is a ketone and more specifically 2-pentanone as it has five carbon atoms.
Regards!
How many liters of C3H6O are present in a sample weighing 25.6 grams?
To Find :
Number of moles of C₃H₆O present in a sample weighing 25.6 grams.
Solution :
Molecular mass of C₃H₆O is :
M = (6×12) + (6×1) + (16×1) grams
M = 94 grams/mol
We know, number of moles of 25.6 grams of C₃H₆O is :
[tex]n = \dfrac{Given \ Mass \ Of \ C_3H_6O }{Molar\ Mass \ Of \ C_3H_6O }\\\\n = \dfrac{25.6}{94}\ mole\\\\n = 0.27 \ mole[/tex]
Hence, this is the required solution.
How many grams water will condense when 56,500 joules of energy is removed from steam at its boiling point
Answer:
Start your streak by answering any question. You'll get bonus points from day 2.
2x²=8.pls help me i really need it
Explanation:
2x²=8
x²=8/2
x=√4
x=2
hope it helps.
Answer:
[tex]\huge \fbox \pink {A}\huge \fbox \green {n}\huge \fbox \blue {s}\huge \fbox \red {w}\huge \fbox \purple {e}\huge \fbox \orange {r}[/tex]
[tex] {2x}^{2} = 8 \\ {x}^{2} = \frac{8}{2} \\ {x}^{2} = 4 \\ x = \sqrt{4} \\ x = 2[/tex]
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ
[tex] \huge\purple{ \mid{ \underline{ \overline{ \tt ꧁❣ ʀᴀɪɴʙᴏᴡˢᵃˡᵗ2²2² ࿐ }} \mid}}[/tex]
(07.01 LC)
Which of the following happens during an exothermic chemical change? (4 points)
Net energy increases.
Heat is absorbed.
Net energy remains constant.
Heat is released.
Answer:
heat is released
Explanation:
there is a release of energy to the surroundings resulting in a net decrease
Heat is released during an exothermic chemical change. Hence, option D is correct.
What is an exothermic reaction?The process in which energy is released where bonds are broken is an exothermic reaction.
For example, combustion is an exothermic reaction where initially energy input along with oxygen and wax react to give heat, carbon dioxide and water.
An exothermic reaction is a "reaction in which standard enthalpy change ΔH⚬ is negative." Exothermic reactions release heat and entail the replacement of weak bonds with a stronger bonds.
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-. How many moles of Pb are contained in 2.49 x 1025 atoms Pb?
Answer: There are [tex]4.13 \times 10^{-3}[/tex] moles of Pb are contained in [tex]2.49 \times 10^{25}[/tex] atoms Pb.
Explanation:
According to the mole concept, 1 mole of every substance contains [tex]6.023 \times 10^{23}[/tex] atoms.
Hence, number of moles present in [tex]2.49 \times 10^{25}[/tex] atoms of Pb are as follows.
[tex]No. of moles = \frac{2.49 \times 10^{25}}{6.023 \times 10^{23}}\\= 4.13 \times 10^{-3} mol[/tex]
Thus, we can conclude that there are [tex]4.13 \times 10^{-3}[/tex] moles of Pb are contained in [tex]2.49 \times 10^{25}[/tex] atoms Pb.
What is the molarity of a solution?
the answer is The number of moles of a solute per kilogram of solvent
Molar concentration is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution.
Name: ___________________________ Date: __________ Period: ______ Solubility Rules Practice Worksheet Name or give the chemical formula for each of the following compounds. State whether they are soluble (will dissolve) or insoluble (will not dissolve) in solution. Use solubility rules. Chemical Formula Name Solubility NH4OH Ra(OH)2 Nickel (III) Acetate CsOH RbCl Potassium Phosphate MgS CaI2 Gold (II) Hydroxide Li3PO4 Platinum (II) Carbonate Barium Nitrate
Given the reaction: N2(g) +2O2(g) ⇌ 2NO2(g) The forward reaction is endothermic. Determine which of the following changes would result in more product being produced.
I. Increase NO2
II. Decrease O2
III. Add a catalyst
IV. Increase the temperature
V. Increase the pressure
A. I and II
B. II, III, and V
C. IV and V
D. II and IV
Answer:
C
Explanation:
increasing the temperature will favour the forward reaction therefore the reaction system will try to counteract that by producing more heat and NO2 therefore increases the amount of products produced
increasing the pressure will favour the forward reaction as it has more moles of substance therefore if the forward reaction is favored, more product will be produced
Answer:
C.) lV and V
Explanation:
I got it correct on founders edtell
Determine which base will work to deprotonate each compound in an acid/base extraction.
Benzene ring with a carboxylic acid on one carbon and a methyl ester group on the opposite carbon __________
Benzene ring with a three carbon chain attached to one carbon. At the other end of the three carbon chain is a hydroxyl group. ___________
Benzene ring with a hydroxyl group attached to one carbon and a tertbutyl group attached to the opposite carbon __________-
Answer:
A common method is to perform an acid-base reaction, which can ... acid is not particularly water-soluble due to its nonpolar aromatic ring, ... An acid-base extraction can be used to extract carboxylic acids from ... carbonic acid (H2CO3) can decompose to water and carbon dioxide gas.
Explanation:
The bases that will work to deprotonate the compounds are :
NaHCO₃ or NaOH.metal alkoxidesNaOHThe Benzene ring with carboxylic acid which is a weak acid can be deprotonated using NaOH or NaHCO₃ because of the weakness of the carboxylic acid.
Metal alkoxides like potassium tertiary butoxide can be used to deprotonate a Benzene ring with three carbon chain attached to a single carbon, and also containing a hydroxyl group is a very weak acid hence the use of Metal alkoxides.
Benzene ring with a hydroxyl group attached is also a weak acid just like the Benzene ring with carboxylic group hence it can also be deprotonated using NaOH
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Show your work. 37.2 moles CO2 to oxygen atoms.
1. Watch how the solubility of a gas changes as pressure is increased and then decreased during the run. Which of the following statements correctly explain the relationship between the solubility of a gas and its pressure?
A. As pressure decreases, the concentration of gas molecules in the solution increases.
B. The concentration of gas particles in the solution is higher at 4.25 atm than at 1.00 atm.
C. The solubility of a gas decreases with a decrease in pressure.
D. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm.
E. Fewer gas molecules are soluble at higher pressures.
F. More gas molecules are soluble as pressure is increased.
G. As pressure is increased, the rate at which gas molecules enter the solution decreases.
2. At a certain temperature, the solubility of N2 gas in water at 3.08 atm is72.5mg of N2 gas/100 g water. Calculate the solubility of N2 gas in water, at the same temperature, if the partial pressure of N2 gas over the solution is increased from 3.08 atm to 8.00 atm .
Answer:
A. As pressure decreases, the concentration of gas molecules in the solution increases.
D. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm.
F. More gas molecules are soluble as pressure is increased.
The solubility is 188.3 mg of N2 gas/100 g water.
Explanation:
As the pressure on the gas decreases, the volume of gas molecules in the solution increases due to having distance from each other. The solubility of nitrogen gas at 2.00 atm is twice the solubility of the gas at 1.00 atm because there is more pressure on the gas molecules so due to more compression, the gas becomes more soluble. More gas molecules are soluble as pressure is increased. The solubility is 188.3 mg of N2 gas/100 g water if the atmospheric pressure is increases from 3.08 atm to 8.00 atm. This value is calculated with the help of formula i.e. P2/P1 = S2/S1.
The volume of a sample of carbon dioxide gas is 26.42 L at 73.0°C. What will its volume be at 92.0°C at constant pressure?
Answer:
[tex]V_2=27.87L[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to solve this problem by using the Charles' law a directly proportional relationship to understand the volume-temperature behavior:
[tex]\frac{V_2}{T_2} =\frac{V_1}{T_1}[/tex]
Thus, we solve for the final volume, V2, and make sure the temperature are in Kelvin as shown below:
[tex]V_2 =\frac{V_1T_2}{T_1} \\\\V_2=\frac{26.42L(92+273.15)K}{(73+273.15)K} \\\\V_2=27.87L[/tex]
Regards!
Acts as the digestive system inside a cell. It helps to break down old or unneeded parts of the cell, and substances that have been brought into the cell from the outside. WHO I AM?
Answer:
I think it is enzymes
Explanation:
3. At 34.0°C, the pressure inside a nitrogen-filled tennis ball with a volume of 148 cm3 is 212
kPa. How many moles of N2 are in the tennis ball?
Answer:
0.0123 mol
Explanation:
Step 1: Convert 34.0 °C to Kelvin
We will use the following expression.
K = °C + 273.15 = 34.0 + 273.15 = 307.2 K
Step 2: Convert 148 cm³ to L
We will use the conversion factors:
1 cm³ = 1 mL1 L = 1000 mL[tex]148cm^{3} \times \frac{1mL}{1cm^{3}} \times \frac{1L}{1000mL} = 0.148L[/tex]
Step 3: Convert 212 kPa to atm
We will use the conversion factor 1 atm = 101.325 kPa.
212 kPa × 1 atm / 101.325 kPa = 2.09 atm
Step 4: Calculate the moles of nitrogen gas
We will use the ideal gas equation.
P × V = n × R × T
n = P × V / R × T
n = 2.09 atm × 0.148 L / (0.0821 atm.L/mol.K) × 307.2 K = 0.0123 mol
True or False: Both molecules and compounds are pure substances.
Answer:
False
Explanation:
Hope this helps!
Answer:
True
Explanation:
It's because both compounds and elements are considered pure substances and a molecules is considered an element.
How much natural gas does Canada have in reserve?
Answer:
Explanation:Marketable and technically recoverable resources
Canada's natural gas reserves are estimated to be 1,383 trillion cubic feet, of which 542 trillion cubic feet is conventional gas, and the rest is unconventional including coal-bed methane, shale and tight gas.
please help- science
1. - new
2. full
3. first quarter
4. last quarter
Answer:
2. Full
Explanation:
A lunar eclipse occurs at a full moon when Earth is directly between the moon and the sun. During a lunar eclipse, Earth blocks sunlight from reaching the moon.
Hope this helps!!
Select the statement that is FLASE about this experiment. Group of answer choices Changing metal solution will affect the redox potential. To ensure consistent data, collect the redox potential values at least three times. Changing temperature will affect the redox potential. To ensure stable reading, insert the conductivity meter in the solution for at least 60 seconds. Changing concentration will affect the redox potential.
Well arranged question is;
Select the statement that is FALSE about this experiment. Group of answer choices;
A) Changing metal solution will affect the redox potential.
B) To ensure consistent data, collect the redox potential values at least three times.
C) Changing temperature will affect the redox potential.
D) To ensure stable reading, insert the conductivity meter in the solution for at least 60 seconds.
E) Changing concentration will affect the redox potential.
Answer:
D) To ensure stable reading, insert the conductivity meter in the solution for at least 60 seconds.
Explanation:
Usually, redox potential is the measure of the ability of chemical elements to gain/lose electrons from/to an electrode respectively and after which they undergo reduction or oxidation respectively.
From online sources on experiments to determine redox potential, and taking into account the nernst equation which is; E_cell = E_0 – (RT/nF)•ln Q
Where;
E_cell is cell potential
E_0 is potential of the cell under standard conditions
R is universal gas constant
T is temperature
n is the number of electrons that are transferred in the redox reaction
F is Faraday's constant
Q is reaction quotient
Now, with all that in mind and looking at the options, the one that is false is option D.
What happens to iron when it melts?
O A. It undergoes a chemical change.
O B. It undergoes a physical change.
O c. Its atoms break apart and form new atoms.
O D. Its atoms combine and form new atoms.
Answer:
B. It undergoes a physical change.
Explanation:
Hello there!
In this case, since we know that chemical changes lead to the formation of new atoms and/or compounds due to the bonds rearrangement of the initial substances and the physical changes occur without changing the composition of the initial substances, we can infer that, since melting is a process that changes the phase of matter from solid to liquid without changing the identity of the initial substance, the answer to this question would be B. It undergoes a physical change. because the other options describe chemical changes.
Best regards!
Answer:
B. It undergoes a physical change.
Explanation:
At room temperature, the iron atoms are in an unusual loosely packed open arrangement; as iron is heated past 912 degrees Celsius, the atoms become more closely packed before loosening again at 1,394 degrees Celsius and ultimately melting at 1,538 degrees Celsius.
How many moles of ammonia would be required to react exactly with 0.554 moles of copper(II) oxide in the following in chemical reaction? 2 NH3(g) + 3 CuO(s)= 3Cu(s) + N2(g) + 3 H2O(g)
The chemical reaction between water and magnesium is?
Answer: hydrogen gas
Explanation: When magnesium interacts with water, it will form a hydrogen gas that ignites violently due to the excessive heat and oxygen supply.
What characteristic should an isotope used for dating have?
O A. It should have a half-life much shorter than the age of the object
being dated.
B. It should have a half-life that is close to the age of the object being
dated.
O C. It should have a half-life that changes with time in the object being
dated.
O D. It should have a half-life much longer than the age of the object
being dated.
Answer:
B
Explanation:
took the test
D. It should have a half-life much longer than the age of the object being dated. When using isotopes for dating purposes, it is important to choose an isotope with a half-life that is significantly longer than the age of the object being dated.
What is the half-life time?The half-life is the time it takes for half of the radioactive isotopes in a sample to decay into stable isotopes. By measuring the ratio of the original radioactive isotope to the decay product, scientists can determine the age of the object.
The majority of the radioactive material would have decayed if the isotope had a half-life substantially less than the age of the artefact, making it challenging to precisely establish the age.
On the other hand, the dating procedure would become more challenging and unpredictable if the isotope in the object being dated (option C) has a half-life that varies over time.
As a result, an isotope with a long half-life offers a stronger basis for precise dating since it enables sufficient radioactive decay to take place, producing quantifiable and trustworthy data.
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In the area with a large population of valuable ocean organisms is called a(n)
Answer:
fishery
An area with a large population of valuable ocean organisms is called a fishery. If it was correct mark me as brainiest