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WILL GIVE BRANLIEST!! EASY BUT I WAS TO LAZY TO LEARN!! WILL FOREVER BE GREATFUL!!!
5. What type of reaction would the heat calculation in previous question be classified as?
A) Natural
B) Chemical
C) Endothermic
D) Exothermic
7. What causes the volume to change in gases? (Choose all that apply)
A) Density
B) Temperature
C) Shape of container
D) Pressure
Answer:
for the first one we need the previous question to be able to answer it. for the second one density and temperature
Explanation:
4.0 g of sodium hydroxide NaOH was dissolved in sufficient water to make up 125 mL of solution.
A) Find the concentration of the solution.
B) What mass of sodium hydroxide could be obtained by heating a 20 mL sample of this solution to dryness?
C) If 30 mL of the solution were mixed with sufficient water to produce 480 mL of a more dilute solution, what would be the concentration of the dilute solution?
D) If 200 mL of the more dilute solution were then mixed with 100 mL of the more concentrated solution, what would be the concentration of the mixed solution?
Answer:
(A) 0.80 M
(B) 0.64 g
(C) 0.050 M
(D) 1.6 M
Explanation:
(A)
Convert 4.0 g to moles with molar mass. Convert 125 mL to L.
4.0 g x (1 mol/39.998 g) = 0.100 mol
125 mL x (1 L/1000 mL) = 0.125 L
Molarity = mol/L
Molarity = 0.100 mol/0.125 L = 0.80 M
(B)
Find moles of NaOH with the molarity you just found. And convert 20 mL to L.
Molarity = mol/L
0.80 M = mol/0.020 L
mol = 0.016
Convert moles to grams with molar mass.
0.016 mol x (39.998 g/1 mol) = 0.64 g
(C)
You know the molarity of a NaOH solution (Part A). 30 mL initial volume and 480 mL final volume are given. Dilution question so use the dilution formula.
M1V1 = M2V2
(0.80 M)(30 mL) = (M2)(480 mL)
M2 = 0.050 M
(D)
Dilution question again, use the dilution formula.
M1V1 = M2V2
(0.80 M)(200 mL) = (M2)(100 mL)
M2 = 1.6 M
Which of the following elements would you expect to have the greatest first ionization energy?
A. Se
B. S
C. K
D. Cl
E. Ca
The element with the greatest first ionization energy among the given options is Se (selenium).
Option (A) is correct.
The first ionization energy refers to the energy required to remove one electron from an atom in its neutral state, forming a positively charged ion. The greater the ionization energy, the more difficult it is to remove an electron.
Considering the elements provided, analyze their positions in the periodic table to make an educated guess:
A. Se (selenium) - Selenium is found in Group 16 (Group 6A) of the periodic table.
B. S (sulfur) - Sulfur is also found in Group 16 (Group 6A) of the periodic table.
C. K (potassium) - Potassium is found in Group 1 (Group 1A) of the periodic table.
D. Cl (chlorine) - Chlorine is found in Group 17 (Group 7A) of the periodic table.
E. Ca (calcium) - Calcium is found in Group 2 (Group 2A) of the periodic table.
Based on the periodic trends, the elements in the upper right portion of the periodic table tend to have the greatest first ionization energies. This is because these elements have a higher effective nuclear charge and a smaller atomic radius.
Comparing the given options, we can see that:
A. Se and B. S are both in Group 16 (Group 6A). Since they are closer to the upper right portion of the periodic table, would expect them to have higher first ionization energies compared to the other options.
C. K is in Group 1 (Group 1A), which is in the far left portion of the periodic table. Elements in this group tend to have lower first ionization energies compared to those in the upper right portion.
D. Cl is in Group 17 (Group 7A), which is closer to the upper right portion of the periodic table compared to Group 1. Therefore, chlorine would have a higher first ionization energy than potassium but likely lower than selenium and sulfur.
E. Ca is in Group 2 (Group 2A), which is to the left of Group 1. Elements in Group 2 have higher first ionization energies compared to those in Group 1 but generally lower than elements in the upper right portion.
Considering these trends, the element with the greatest first ionization energy among the given options is:
A. Se (selenium)
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What is the percent by volume of a solution that has 45 mL of ethanol CH3OH dissolved in 255 mL of water?
Answer:
Percent volume-volume (%(v/v)) = 100 x (volume of solute / volume of solution)
Percent volume-volume (%(v/v)) = 100 x (volume of solute / volume of solution)ex. 20 ml of methanol dissolved in enough water to make 200 ml of solution would result in a 10 % methanol solution
Percent volume-volume (%(v/v)) = 100 x (volume of solute / volume of solution)ex. 20 ml of methanol dissolved in enough water to make 200 ml of solution would result in a 10 % methanol solution-the units may be any units of volume you chose - as long as they are consistent
Percent volume-volume (%(v/v)) = 100 x (volume of solute / volume of solution)ex. 20 ml of methanol dissolved in enough water to make 200 ml of solution would result in a 10 % methanol solution-the units may be any units of volume you chose - as long as they are consistent-this concentration unit is most often used when mixing two liquids
What does it mean to dilute a solution?
Answer:
Dilution is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to the solution
Ammonia, nh3, is used in numerous industrial processes, including the production of pharmaceuticals such as sulfonamide and antimalarials and vitamins such as the b vitamins. The equilibrium equation for the synthesis of ammonia (sometimes known as the haber process) is n2(g)+3h2(g)⇌2nh3(g) part a the haber process is typically carried out at a temperature of approximately 500∘c. What would happen to the rate of the forward reaction if the temperature were lowered to 100∘c?
If the temperature were lowered to 100∘c, the rate of the forward reaction would decrease.
Ammonia (NH3) is commonly used in various industrial processes such as the synthesis of pharmaceuticals like antimalarials and vitamins like B vitamins.
The equation for the production of ammonia is N2(g) + 3H2(g) ⇌ 2NH3(g). The Haber process is carried out at a temperature of about 500°C.
If the temperature is decreased to 100°C, the rate of the forward reaction will decrease. In other words, the equilibrium position will shift in the direction of the reverse reaction. The decrease in temperature will lower the kinetic energy of the reactant molecules, thus reducing their rate of collision and therefore decreasing the rate of the forward reaction.
:If the temperature were lowered to 100∘c, the rate of the forward reaction would decrease.
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Is it true that all atoms strive to have eight electrons in their outermost
shell?
YESS It is true!!. In general, atoms are most stable, least reactive, when their outermost electron shell is full. Most of the elements important in biology need eight electrons in their outermost shell in order to be stable, and this rule of thumb is known as the octet rule.
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1. Which graph represents the endothermic reaction?
2. Which graph represents the exothermic reaction?
Answer:
A is endothermic, B is exothermic.
Explanation:
I actually just looked at the bottom of the graph. Endothermic reactions absorb energy, but exothermic reactions release it. Hope this helped!
N3- ion name pls help!!
Answer:
N with a charge of (-3) is nitride
Explanation:
Sometimes the number of electrons in an atom changes. These atoms are called what
Answer:
ions
Explanation:
if δg° of the following reaction is –110 kj/mol, what is e°cell? (f = 96,500 C • mol^-1) A^3-(aq) + 3B(s) → A(s) +3B- (aq)
a. + 0.38 V b. - 0.09 V c. - 0 38 V d. + 0.00038 V e. + 0.09 V
The standard cell potential (E°cell) of the reaction is found to be + 0.38 V, hence, option A is correct.
We will be usig the equation,
E°cell = (ΔG° / -nF) standard Gibbs free energy change is ΔG°, number of electrons transferred in the balanced equation is n, and Faraday constant (96,500 C/mol) is F. In the given reaction, 3 electrons are transferred, so n = 3.
Given ΔG° = -110 kJ/mol and F = 96,500 C/mol, we can substitute these values into the equation to calculate E°cell,
E°cell = (-110,000 J/mol / (-3 * 96,500 C/mol))
E°cell = 0.38 V
Therefore, the answer is, a. + 0.38 V
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Part A)
Which of the species in the forward reaction below is acting as a base?
HCO3- + H2O ⇌ CO32- + H3O+
Part B
Which of the following are conjugate acid/base pairs? Select all that apply.
H2PO4- and HPO42-
H3O+ and OH-
HCl and Cl-
H2CO3 and CO32-
HCl and NaOH
In the direct reaction HCO3- + H2O ⇌ CO32- + H3O+, HCO3- acts as a base.
H2PO4- and HPO42-
H3O+ and OH-
H2CO3 and CO32 are
What is conjugate acid?
An acid and a base which differ only by the presence or absence of a proton are called a conjugate acid-base pair.
Part A:
In the direct reaction HCO3- + H2O ⇌ CO32- + H3O+, HCO3- acts as a base. This is because it accepts a proton (H+) from water (H2O) to form H3O+ (a hydronium ion). In this reaction, HCO3- acts as a Bronsted-Lowry base.
Part B:
Conjugate acid/base pairs among the options are:
H2PO4- and HPO42- (acid/base conjugate pair)
H3O+ and OH- (acid/base conjugate pair)
HCl and Cl- (not a conjugate acid/base pair; both are ions but not related by proton transfer)
H2CO3 and CO32- (acid/base conjugate pair)
So the correct answers are:
H2PO4- and HPO42-
H3O+ and OH-
H2CO3 and CO32-
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Using the table of average bond energies below the delta H for the reaction is __ kJ. Bond: C equivalence c C-C H-I C-I C-H D (kJ/mole): 839 348 299 240 413 A. +63 B. +160 C. -63
D. -217 E. -160
The delta H for the reaction can be calculated using average bond energies. Based on the provided table, the bond energies are as follows: C-C (839 kJ/mol), H-I (348 kJ/mol), C-I (299 kJ/mol), and C-H (240 kJ/mol). To determine the delta H, we need to subtract the sum of the bond energies broken from the sum of the bond energies formed.
In this case, the bonds broken are C-C and H-I, with energies of 839 kJ/mol and 348 kJ/mol respectively. The bonds formed are C-I and C-H, with energies of 299 kJ/mol and 240 kJ/mol respectively. Calculating the delta H: Delta H = (Energy of bonds broken) - (Energy of bonds formed) = (839 kJ/mol + 348 kJ/mol) - (299 kJ/mol + 240 kJ/mol) = 1187 kJ/mol - 539 kJ/mol = 648 kJ/mol. Therefore, the delta H for the reaction is +648 kJ/mol. Since none of the given options match this value exactly, it seems there may be an error in the options provided.
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How many moles of oxygen are required in order to produce 4 moles of
water?
If there is a third-quarter moon on July 2 , what is the approximate date of the next full moon?
Answer:
July 23
Explanation:
6. List two (2) ethical issues that the healthcare provider has a public duty to report.
Answer: Communicable diseases, abuse gunshot wounds and forensic medicine
Explanation:
please help
Why does a smoke detector use alpha radiation rather than beta or gamma radiation?
Answer:To be honest i dont know
Explanation:
e
Answer:
Explanation:
Alpha radiation ionizes the air. When smoke interaccts with the ionized particles it causes the alarm to sound.
draw the major e2 reaction product formed when (1r,2s,4s)‑2‑chloro‑4‑methyl‑1‑(propan‑2‑yl)cyclohexane reacts with hydroxide ion in dmso. chirality is graded.
The major E2 reaction product formed when (1R,2S,4S)-2-chloro-4-methyl-1-(propan-2-yl)cyclohexane reacts with hydroxide ion in DMSO is (1S,2R,4S)-2-methyl-1-(propan-2-yl)cyclohexene.
In an E2 (elimination) reaction, a hydrogen atom and a leaving group are removed from adjacent carbon atoms, resulting in the formation of a double bond. In this case, the leaving group is the chloride ion (Cl-) and the hydrogen atom is removed from the carbon adjacent to the chlorine atom.
The given starting compound, (1R,2S,4S)-2-chloro-4-methyl-1-(propan-2-yl)cyclohexane, has a chiral center at carbon 2, which is marked as (S). When the hydroxide ion (OH-) attacks the carbon adjacent to the chlorine atom, the chlorine leaves and a hydrogen from the adjacent carbon is also removed. The resulting product is (1S,2R,4S)-2-methyl-1-(propan-2-yl)cyclohexene.
It's important to note that the stereochemistry of the starting compound and the resulting product is represented by the (R) and (S) designations, indicating the arrangement of the substituents around the chiral carbon atoms.
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What is hydrochloric acid used for?
Cleaning
Warfare
Middle school science class
to make glue
Answer:
To make glue. aaaaaaaaa
Answer:
Cleaning
Explanation:
Hydrochloric acid is an ingredient in household cleaners because it helps clean tough stains.
1. how many unpaired electrons are in the boron atom?
this atom is ... a. paramagnetic ... b. diamagnetic ....
2. How many unpaired electrons are in the iron atom? This atom is ...
A. Paramagnetic...
B. Diamagnetic...
1) The boron atom has only one unpaired electron, making it paramagnetic.
2) Boron atom has one unpaired electron, making it paramagnetic.Iron atom has four unpaired electrons, making it paramagnetic.
1. Boron atom and unpaired electrons Boron is a chemical element with the symbol B and atomic number 5. It is a trivalent metalloid and has three valence electrons. The electron configuration of boron is 1s² 2s² 2p¹. Therefore, the boron atom has only one unpaired electron, making it paramagnetic.2. Iron atom and unpaired electronsIron is a chemical element with the symbol Fe and atomic number 26. It is a metal and has two valence electrons. The electron configuration of iron is [Ar] 3d⁶ 4s². Therefore, the iron atom has four unpaired electrons, making it paramagnetic. Answer:Boron atom has one unpaired electron, making it paramagnetic.Iron atom has four unpaired electrons, making it paramagnetic.
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Which chemical equation is a model of a decomposition reaction?
Answer:
The answer is C
It's a model of Decomposition reaction
8th silberberg, sample problem 13.5. find the concentration of calcium ion (in ppm) in a 2.43 g pill that contains 44.6 mg of ca2 . enter to 0 decimal places.
The concentration of calcium ion in the pill is 18,320 ppm.
To calculate the concentration of calcium ion in parts per million (ppm), we need to determine the mass of calcium ion in the pill and divide it by the mass of the pill, then multiply by 1,000,000.
Mass of the pill = 2.43 g
Mass of Ca^2+ = 44.6 mg = 0.0446 g
Now, we can calculate the concentration in ppm:
Concentration of Ca^2+ (ppm) = (Mass of Ca^2+ / Mass of the pill) * 1,000,000
Concentration of Ca^2+ (ppm) = (0.0446 g / 2.43 g) * 1,000,000
Concentration of Ca^2+ (ppm) ≈ 18,320 ppm
The concentration of calcium ion in the pill is approximately 18,320 ppm.
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how to find the concentration of a solution that is 100 times less than another solution
By dividing the concentration of the reference solution by 100, you will obtain the concentration of the desired solution, which is 100 times less concentrated than the reference solution.
To find the concentration of a solution that is 100 times less than another solution, you can follow these steps:
1. Determine the concentration of the reference solution. Let's denote it as [A]₀.
2. Calculate the concentration of the desired solution. Let's denote it as [A].
3. Since the desired solution is 100 times less concentrated than the reference solution, you can divide the concentration of the reference solution by 100 to obtain the concentration of the desired solution:
[A] = [A]₀ / 100
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When a small piece of sodium metal is dropped into a beaker of water, hydrogen gas (H2) and a solution of sodium hydroxide (NaOH) are products. The solution becomes warm.
Answer:
The reaction is exothermic as the solution becomes warm.
Explanation:
Hello there!
In this case according to the described reaction between sodium metal and water, we can write up the chemical equation whereas the products turn out to be sodium hydroxide and hydrogen gas:
[tex]2Na+2H_2O\rightarrow 2NaOH+H_2[/tex]
Moreover, these reactions are known to be highly exothermic, for that reason the solution becomes warm as the reaction releases heat as it goes to completion.
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What does the period number tell about the energy levels occupied bye electrons in an atom
Answer:
The period number tells which is the highest energy level occupied by the electrons.
Explanation:
The period number (denoted by n) is the outer energy level that is occupied by electrons in an atom.The period number that an element is in, is the number of energy levels that the element has.When we move across a period from left to right in a periodic table the number of electrons in atoms increases within the same orbit.For a galvanic cell that uses the following two half-reactions, write the balanced equation and how many moles of Pb(s) are oxidized by five moles of Cr2O72-?
Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l)
Pb(s) → Pb2+(aq) + 2 e-
(Please show work and thank you for taking the time to answer.)
The balanced equation is 6 Pb(s) + 6 Cr2O72-(aq) + 42 H+(aq) → 12 Cr3+(aq) + 42 H2O(l) + 6 Pb2+(aq). 6 moles of Pb(s) are oxidized for every 6 moles of Cr2O72- consumed. If 5 moles of Cr2O72- are used, it will oxidize 5 moles of Pb(s).
First, we need to balance the two half-reactions. Let's start with the reduction half-reaction of Cr2O72-: Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l). To balance the oxygen atoms, we add 7 H2O to the left side: Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l). Next, we balance the hydrogen atoms by adding 14 H+ to the right side:
Cr2O72-(aq) + 14 H+(aq) + 6 e- → 2 Cr3+(aq) + 7 H2O(l) + 14 H+(aq)
Now, let's balance the oxidation half-reaction of Pb: Pb(s) → Pb2+(aq) + 2 e-. The equation is already balanced. To combine the two half-reactions, we multiply the reduction half-reaction by 6 and the oxidation half-reaction by 6 to ensure that the electrons cancel out: 6 Cr2O72-(aq) + 42 H+(aq) + 36 e- → 12 Cr3+(aq) + 42 H2O(l) + 84 H+(aq). 6 Pb(s) → 6 Pb2+(aq) + 12 e-. Now, we can write the balanced equation: 6 Pb(s) + 6 Cr2O72-(aq) + 42 H+(aq) → 12 Cr3+(aq) + 42 H2O(l) + 6 Pb2+(aq).
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The characteristics of metallic bonds fit nicley into a predictable pattern. True or False?
Answer:
True
Explanation:
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List and describe the 2 main causes of species extinction happening today.
Answer:
habitat destruction, overexploitation, climate change, nitrogen pollution, and invasive species.
Explanation:
Main Modern Causes of Extinction:
habitat destruction - the process by which a natural habitat becomes incapable of supporting its native species.
overexploitation - harvesting a renewable resource to the point of diminishing returns.
climate change - includes both global warmings driven by human emissions of greenhouse gases and the resulting large-scale shifts in weather patterns.
nitrogen pollution - a form of water pollution, refers to contamination by excessive inputs of nutrients.
invasive species - an introduced organism that negatively alters its new environment.
A researcher is trying to identify whether household substances are basic. Which approach would BEST help the researcher
investigate whether substances are basic?
O A. Mix each substance with a weak base and record the results.
OB. Test each substance with red litmus paper.
O C. Observe each substance and record its color.
OD Test each substance with blue litmus paper.
Answer:
I think B
Explanation:
Red litmus paper is used more to find bases, blue litmus paper changes better when coming to find acids. So I believe it is B
The best approach best investigate whether substances are basic is to test each substance with red litmus paper.
What is basic compound?Basic compounds are those which have a pH value in between the range of 7.1 to 14.
Red litmus paper changes its color from red to blue when comes in the contact of basic compounds. So to check the basicity of household substance we should use red litmus paper.
Bases are reacting with only acids means bases shows no reaction with base and if we use weak base then we will not get the desired result as weak bases are partially dissociates only.Color will not gives idea about basicity and acidity.Red litmus paper is used to test the acidity of substance as it turns blue when comes in contact of acids.Hence test each substance with red litmus paper.
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Which compound has the shortest carbon-carbon bond length?
a. CH3CH3
b. CH2CH2
c. HCCH
d. All bond lengths are the same.
The correct answer is c. C₂H₂, which has the shortest carbon-carbon bond length.
The compound with the shortest carbon-carbon bond length is c. C₂H₂, which refers to ethyne or acetylene. Ethyne consists of a triple bond between the two carbon atoms, resulting in a shorter bond length compared to the other compounds listed.
In option a, CH₃CH₃ (ethane), the carbon-carbon bond is a single bond, which is longer than a triple bond.
In option b, CH₂CH₂ (ethylene), the carbon-carbon bond is a double bond, which is longer than a triple bond but shorter than a single bond.
Therefore, the correct answer is c. C₂H₂, which has the shortest carbon-carbon bond length due to the presence of a triple bond between the carbon atoms.
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