Use the periodic table to answer this question.
How many moles of He are in 16 g of the element?
A 4.0 mol
B 1.0 mol
C 8.0 mol
D 16 mol
Answer:
A. 4.0 mol
Explanation:
Divide 16 g by the molar mass of He, which is 4.0 g/mol.
16 g / 4.0 g/mol = 4.0 mol
Which element had the smallest atomic radius
Answer:
helium is the answer
Explanation:
helium is the smallest element in francium is the largest hope this helps
Why aren't gas molecules attracted to each other? Explain.
Answer:
As gas is compressed, the individual molecules begin to move in each others way creating a very repulsive force. It acts to oppose any further volume decrease. At very close distances, all molecules repel each other as their electron clouds emerge.
Explanation:
Some students have said that a buffer is like a proton (H ) sponge. Evaluate this statement and explain both how a buffer is like a sponge and how it is not like a sponge. For your explanation, include chemical equations, data, and create and explain molecular-level drawings. (Question is taken from Orgill and Sutherland, 2008.) (Saloni)
Answer:
i) Buffer absorbs H^+ and OH^- ions preventing large changes in pH when small amounts of acid or base is added but when large amounts of acid or base is added there will be a change in pH
ii) absorption of liquid is related to a chemical reaction for a buffer system but it is not related a chemical reaction for a proton( H ) sponge.
Explanation:
i) Buffer like a proton ( H ) sponge
Buffer absorbs H^+ and OH^- ions preventing large changes in pH when small amounts of acid or base is added but when large amounts of acid or base is added there will be a change in pH
The pH of a Buffer follows the Henderson-Hasselbach model
pH = pKa + Log ([A-]/[HA])
when base is added
HA + OH^- -------> A- + H2O
when acid is added
A^- + H^+ ---------> HA
ii) Buffer not like a proton ( H ) sponge
absorption of liquid is related to a chemical reaction for a buffer system but it is not related a chemical reaction for a proton( H ) sponge.
PLEASE HURRY! What is the name of this alkane?
A skeletal model has a hexagon ring with points at the top and bottom. C H 3 is bonded to the top point, and a carbon and another C H 3 are bonded to the bottom right point.
1-methyl,3-ethylnonane
1-methyl,5-ethylisohexane
1-ethyl,3-methylcyclohexane
1-ethyl,5-methylcyclohexane
Answer:
C. 1-ethyl, 3-methylcyclohexane
(Photo for proof at the bottom.)
Explanation:
The 1-ethyl is because you start numbering from the longest branch, towards the next closest branch. Prefix "eth-" means two, there are 2 carbons in the longest branch. 3-methyl is because the next branch is at number 3, and prefix "meth-" means 1, there is 1 carbon in that chain. "Cyclo" in cyclohexane means the skeletal model is shaped like a ring, and the "hexane" means there are 6 carbons in the ring. Prefix "hex" means 6.
Here's a photo of the unit review on Edge. Refer to the 2nd attachment for a visualization.
Please click the heart if this helped.
Answer:
C. 1-ethyl,3-methylcyclohexane
Explanation:
Bacteria can be heterotrophs or autotrophs
true or false?
Answer:
True
Explanation:
I learned about it a few years ago
which behavior is a innate adaptation a.hunting in packs b.fighting for portection .c mating d. all behaviors are innate
Answer:
c. mating
Explanation:
Pleaseeeee helpppp!!!
Answer:
a triple bond posana pi maka tulong
The reaction CO2+H2O=H2OCO3 is classified as
.50 ml of a solution are diluted to a volume of 100 ml. The concentration of the diluted
solution is 2 M. What was the concentration of the original solution?
pls answer asap! will mark as brainly ist!!
Answer:
4 M
Explanation:
To answer this problem we can use the following formula:
V₁C₁ = V₂C₂Where the subscript 1 refers to the volume and concentration before diluting, and 2 refers to volume and concentration after diluting.
Meaning that in this case we can write:
50 mL * C₁ = 100 mL * 2 MWe can now solve for C₁:
C₁ = 4 MWhat material would make the most efficient hot pack?
●Lithium Chloride
●Sodium Chloride
●Sodium Hydroxide
●Potassium Chloride
Answer:
Lithium Chloride would be the best one
Sodium Hydroxide would be the second best
Explanation:
A solution is made by dissolving 62.42 g of ammonium sulfate in enough
water to make 50.0 mL of solution. What is the molarity of this solution?
(**Use only numerical answers with 3 significant figures. The units are given
in the question.)
Answer:
9.46 M
Explanation:
Molarity is a measure of the molar concentration of a solution. It can be calculated by the following formula
Molarity = number of moles/volume
Using moles = mass/molar mass
Molar Mass of Ammonium sulfate (NH₄)₂SO₄ =
{14 + 1(4)}2 + 32 + 16(4)
= {14 + 4}2 + 32 + 64
= 18(2) + 96
= 36 + 96
= 132g/mol
mole = mass/molar mass
mole = 62.42 ÷ 132
mole = 0.473mol
- Molarity = mole ÷ volume
Volume = 50.0 mL = 50/1000 = 0.05 L
Molarity = 0.473 ÷ 0.05
Molarity = 9.46 M
What process is represented by this redox equation?
C6H12O6 + 602 -> 6H20 + 6CO2
A. Rusting
B. Photosynthesis
C. Cellular respiration
D. Combustion
The redox equation C6H12O6 + 6O2 -> 6H2O + 6CO2 represents the process of cellular respiration. Option C
Cellular respiration is a biochemical process that occurs in living organisms, including plants and animals, to convert organic compounds, such as glucose (C6H12O6), into usable energy in the form of adenosine triphosphate (ATP). It is the primary process by which cells derive energy to carry out their functions.
In the given equation, glucose (C6H12O6) is being oxidized, losing electrons, and releasing carbon dioxide (CO2) as a byproduct. This oxidation process results in the production of energy-rich molecules, such as ATP.
Additionally, oxygen (O2) is being reduced, accepting the electrons from glucose and combining with hydrogen (H) to form water (H2O). This reduction process allows for the transfer of electrons and the generation of energy.
The process of cellular respiration is essential for the survival and functioning of organisms, as it provides the necessary energy for various metabolic activities, growth, and maintenance of cellular processes.
It is a fundamental metabolic pathway found in both plants and animals, enabling them to extract energy from organic molecules through the oxidation of glucose or other fuel sources.
Therefore, option C, cellular respiration, is the correct answer that represents the process described by the given redox equation.
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Which statement is accurate about variations?
Organisms with variations that give an advantage are more likely to survive
Organisms with variations are less likely to pass these variations to their offspring
In all cases vanations become more common in a population
In all cases variations affect how likely it is that an organism reproduces
Answer:
A,C,D
Explanation:
Variations effect the likelyhood of survival for a organism, it can give off an advantage or disadvantage.
Brainliest? pls
2. Gas A has twice as much mass as Gas B. Compared to one mole of gas A, one mole of
gas B contains:
a) one-half as many particles
b) the same number of particles
c) twice as many particles
d) 22.4 times as many particles
Plants are divided into three groups based on the
Answer:Scientists have identified more than 260,000 kinds of plants. They classify plants according to whether they have body parts such as seeds, tubes, roots, stems, and leaves. The three main groups of plants are seed plants, ferns, and mosses.
Explanation:
hope i help
Interpret the following equation for a chemical reaction using the coefficients given:
H2(g) + Cl2(g)-------- 2HCl(g)
On the particulate level:
______ of H2(g) reacts with _______ of Cl2(g) to form two molecules of HCl(g).
On the molar level:
______of H2(g) reacts with _______of Cl2(g) to form two moles of HCl(g).
Answer: 1 molecule of [tex]H_2[/tex] reacts with 1 molecule of [tex]Cl_2[/tex] to give 2 molecules of HCl.
1 mole of [tex]H_2[/tex] reacts with 1 mole of [tex]Cl_2[/tex] to give 2 moles of HCl.
Explanation:
The given balanced reaction is:
[tex]H_2(g)+Cl_2(g)\rightarrow 2HCl(g)[/tex]
On the particulate level :
1 molecule of [tex]H_2[/tex] reacts with 1 molecule of [tex]Cl_2[/tex] to give 2 molecules of HCl.
On molar level:
1 mole of [tex]H_2[/tex] reacts with 1 mole of [tex]Cl_2[/tex] to give 2 moles of HCl.
A strong acid, such as hydrochloric acid cannot be poured down a sink because it will react and dissolve the metal in the pipes. Yet a strong base, commonly found in drain cleaner, can be poured down a sink. A strong acid can be neutralized with a strong base, creating a salty water solution. What will happen when 10.0 g of hydrochloric acid were mixed with 10.5 grams of calcium hydroxide?
Answer:
15.2 grams of calcium chloride are produced and HCl is the limiting reactant.
Explanation:
Hello there!
In this case, according to the described scenario, it is possible to realize that the reaction between hydrochloric acid and calcium hydroxide is:
[tex]2HCl+Ca(OH)_2\rightarrow CaCl_2+2H_2O[/tex]
Whereas there is a 2:1 mole ratio of the acid to the base. In such a way, with the given masses, we can compute how much calcium chloride product is produced due to the chemical reaction via stoichiometry:
[tex]m_{CaCl_2}^{by HCl}=10.0gHCl*\frac{1molHCl}{36.46gHCl}*\frac{1molCaCl_2}{2molHCl} *\frac{110.98gCaCl_2}{1molCaCl_2} =15.2gCaCl_2\\\\m_{CaCl_2}^{by Ca(OH)_2}=10.5gHCl*\frac{1molCa(OH)_2}{74.09gCa(OH)_2}*\frac{1molCaCl_2}{1molCa(OH)_2} *\frac{110.98gCaCl_2}{1molCaCl_2} =15.7gCaCl_2[/tex]
Whereas we infer that the correct amount is 15.2 g since HCl is the limiting reactant as it produces the fewest grams of the desired product. Consequently, the calcium hydroxide is the excess reactant here.
Regards!
Write a mechanism for the conversion of the aldol addition product, 3-hydroxy-3-(4-nitrophenyl)-1-(2-pyridyl)-1-propanone, to the aldol condensation product, (E)-3-(4-nitrophenyl)-1-(2-pyridyl)-1-propenone. Be as complete as possible and show electron flow for all steps.
Solution :
"Aldol" stands for the abbreviation, aldehyde and alcohol. When a ketone or an aldehyde's enolate reacts with the carbonyl of a molecule at the alpha carbon, under the acidic or basic conditions so as to obtained the ketone or β-hydroxy aldehyde, is known as an aldol reaction.
For the conversion of the aldol addition product of a 3-hydroxy-3-(4-nitrophenyl)-1-(2-pyridyl)-1-propanone to an aldol condensation product of (E)-3-(4-nitrophenyl)-1-(2-pyridyl)-1-propenone, the mechanism is given in the diagram a below :
What do particulates in the atmosphere do?
A: They trap heat
B: They help plants to grow better
C: They shield Earth's surface from harmful solar radiation
D: They nucleate water vapor to form clouds.
Lab: Enthalpy.
What were the learning goals of this lab experiment? Check all that apply.
to use mass and temperature data to do computations involving heat
to demonstrate that different reactions have different enthalpies
to compute a reaction’s enthalpy directly using mass measurements and a calorimeter
to compute the enthalpy of a reaction that cannot be measured directly using a simple calorimeter
Hess
’s law allows you to find the net enthalpy of the magnesium combustion by adding the enthalpies of intermediate reactions.
To find the enthalpy of a reaction in the lab, you measured the
mass
of the reactants
and the
temperature
change during the reaction.
In both Reactions 1 and 2, the temperature change was
positive
, meaning that the
reactions
gave off
heat.
Answer:
to use mass and temperature data to do computations involving heat
to compute a reaction’s enthalpy directly using mass measurements and a calorimeter
To find the enthalpy of a reaction in the lab, you measured the mass
of the reactants
and the
temperature
change during the reaction.
Explanation:
Was that good?
Enthalpy is a thermodynamic system's internal energy total as well as the volume times pressure ratio.
What is Enthalpy?Enthalpy is a property or state function that resembles energy; it has the same dimensions as energy and is therefore measured in joules or ergs. The value of enthalpy is solely dependent on the temperature, pressure, and composition of the system, not on its history.
Enthalpy, denoted by the symbol H, is the sum of the internal energy, denoted by E, and the product of the pressure and volume, denoted by PV.
The change in internal energy is equal to the heat transmitted to, less the work done by, the system, according to the law of energy conservation.
Therefore, Enthalpy is a thermodynamic system's internal energy total as well as the volume times pressure ratio.
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Can someone help me with this 3 questions I’ll mark brainliest spam answers will be reported
Answer:
1. stomach
2. veins
3.both are functions
Explanation:
1. The cardiovascular system consists of the heart, and a closed system of vessels called arteries, veins, and capillaries. (Stomach is not included)
2.The inferior vena cava is the largest vein in the body and carries deoxygenated blood from the lower half of the body into the heart
3. Blood transports oxygen and nutrients to the lungs and tissues, and brings waste products to the kidneys and liver, which filter and clean the blood.
Hope this helps!
Rusting is a chemical reaction between Iron metal [Fe(s)] and oxygen gas [O2(g)] in a slightly acidic environment. Rusting is actually a multi-step reaction, however it has the net overall reaction of:
4Fe+3O2--->2FeO3
If 100.0 g of iron metal are converted into rust, how many moles of rust will have formed? (Assume unlimited oxygen gas.)
*Hint* You already converted 100.0 g of Fe into moles of Fe in a previous question, start there.
Answer:
0.895 mole of Fe₂O₃.
Explanation:
We'll begin by calculating the number of mole in 100 g of Fe. This can be obtained as follow:
Molar mass of Fe = 56 g/mol
Mass of Fe = 100 g
Number of mole of Fe =?
Mole = mass / molar mass
Number of mole of Fe = 100 / 56
Number of mole of Fe = 1.79 mole
Finally, we shall determine the number of mole of Fe₂O₃ produced by the reaction of 100 g (i.e 1.79 moles) of Fe. This can be obtained as follow:
4Fe + 3O₂ — > 2Fe₂O₃
From the balanced equation above,
4 moles of Fe reacted to produce 2 moles of Fe₂O₃.
Therefore, 1.79 moles of Fe will react to produce = (1.79 × 2)/4 = 0.895 mole of Fe₂O₃.
Thus, 0.895 mole of Fe₂O₃ was obtained from the reaction.
Which Sl unit would be most appropriate for expressing the mass of this
animal?
Answer: Kilograms
Explanation: Milliliters and Kilometers are the wrong unit of measurement, and Milligrams are too small. Kilograms would be most appropriate to measure the weight of a heavy animal.
Estimate your de Broglie wavelength when you are running. (For this problem use h = 10^−34 in SI units and 1 lb is equivalent to 0.45 kg.) For the computation, estimate how fast you can run in meters per second.
A. your running speed ______ m/s
B. your mass ______kg
C. your de Broglie wavelength ______ m
Answer:
A. your running speed 1.5 m/s
B. your mass 70 kg
C. your de Broglie wavelength [tex]6.32x10^{-36}[/tex]m
Explanation:
Hello there!
In this case, since the equation for the calculation of the Broglie wavelength is:
[tex]\lambda =\frac{h}{m*v}[/tex]
We can assume a running speed of about 1.5 m/s and a mass of 70 kg, so the resulting Broglie wavelength is:
[tex]\lambda =\frac{6.626x10^{-34}kg\frac{m}{s} }{70kg*1.5\frac{m}{s} }\\\\\lambda =6.32x10^-36m[/tex]
Best regards!
The process of breaking a compound down into its elements is called
rearrangement
recombination
decomposition
dessication
4. What is the molarity of a solution that contains 65g of sodium nitrate in 750? ml of solution?
Answer:
1.02 M
Explanation:
Solution contains 65g of sodium nitrate
Volume of solution = 750 ml
Now, Molar mass of sodium nitrate from online values = 84.9947 g/mol
Thus, it means 84.9947 g/mol of sodium nitrate dissolved in 1000 mL of water will be equal to 1 M molarity.
Thus;
Molarity of solution = (65/750) × (1000) × (1/84.9947) = 1.02 M
When would a topographic map be useful?
Answer:
Topographic maps are used by hikers and backpackers to plan routes, estimate travel times, find water, good campsites, and track their progress on hikes. They're designed to depict the three dimensional shape of the world (mountains, valleys, plains, etc.)
Explanation:
which sentences in the passage are true?
Answer:
First and last sentence .♀️
Explanation:
An important thing to keep in mind about the Reading Comprehension section of the GRE as we use PowerPrep online to study is that it is just that—reading comprehension. In other words, as difficult as it may seem, and it can be pretty tricky, the test makers will always give us all the information we need in the passage to answer the question.
Calculate the pH when [H]= 7.5 x 10^-12M
Answer:
11.1249387366083
Explanation:
you do -log([H+]