Answer:
Ancient CO₂ levels can be measured from
1) Air bubbles trapped in deep ancient ice cores (up to 800,000 years ago) or
2) Tree rings (up to 10,000 years ago)
Explanation:
The percentages of CO₂ concentration in the atmosphere from previous or ancient times are found by analyzing the CO₂ content in trapped air located in the deep ancient ice cores present in Antarctica and Greenland such as the EPICA Dome C cores
As the ice is drilled though, the air released from trapped bubbles are captured for analysis and the time frame for the captured bubbles can date back up to 800,000 years
Ancient CO₂ levels can also be measured from tree rings which provide ancient CO₂ levels up to 10,000 years
The disinfectant hydrogen peroxide (H2O2)
decomposes to form water and oxygen gas.
How much O2 will result from the decomposition of 2.22 mol of hydrogen peroxide?
Answer:
1.1 mol of O2
Explanation:
First we need the balance chemical equation which is
2 H2O2 -------> 2 H2O + O2
This is important because in stoichiometry you can go from units of one thing to other by using mole ratios, here the mole ratio is 2 mol of H2O2 for one mole of O2.
[tex]2.2 mol H2O2 \frac{1mol O2}{2 mol H2O2}[/tex] = 1.1 mol of O2
Se construye una pila galvánica con una barra de cobre sumergida en una disolución 1M de cationes Fe+2 y una barra de plata sumergida en una disolución 1M de da cationes Ag+ , Calcular el potencial estándar de la celda teniendo en cuenta que a 25°C: Cu+2/Cu = -0.34V Ag+/Ag = 0.80V
Answer:
El potencial celular estándar, [tex]E_{cell}[/tex] is +0.46 V
Explanation:
Las reacciones de media célula son;
Media reacción del ánodo Cu²⁺ + 2e⁻ ↔ Cu, E ° = 0.34 V
Media reacción catódica 2Ag + 2e⁻ ⁻ 2Ag, E ° = 0.80 V
Sin embargo tenemos para hierro Fe²⁺ + 2e⁻ ↔ Fe, E ° -0.44 V
y Fe³⁺ + e⁻ ↔ Fe²⁺, E ° = 0.77 V
que es más alta que la del cobre presente, por lo tanto, el cobre se oxidará en el ánodo
Por lo tanto, en el ánodo, tendremos
Cu → Cu²⁺ + 2e⁻ (E ° = -0.34 V)
En el cátodo
2Ag + 2e⁻ → 2Ag (E ° = 0.80 V)
[tex]E_{cell} = E_c + E_a = -0.34 + 0.8 = +0.46 \, V[/tex]
El potencial celular estándar, [tex]E_{cell}[/tex] = +0.46 V
The pictures to the right, show two different models
of the atom. Type in the letter of your answer.
Which model best represents Dalton's atomic
theory?
Answer:
The pictures to the right, show two different models of the atom. Type in the letter of your answer.
Which model best represents Dalton’s atomic theory?
B
Which model best represents the modifications to the theory that Thomson’s results made necessary?
A
The model that represents Dalton's atomic model is the B model.
Dalton's Atomic TheoryDalton was a scientist who described how the atom is characterized, stating that the atom would be a massive and indestructible sphere, that is, it was not divided into subparticles (electrons, protons and neutrons).
Thus, model B is the most suitable according to Dalton's statements.
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The reaction 2 NO(g) ⇌ N2(g) + O2(g) has a value of Keq = 2400 at a temperature of 2000 K. If 0.570 mol of NO(g) is initially placed in a 3.0 L container, calculate the equilibrium concentrations of each gas
Answer:
[tex][N_2]_{eq}=0.094M[/tex]
[tex][O_2]_{eq}=0.094M[/tex]
[tex][NO]_{eq}=0.002M[/tex]
Explanation:
Hello,
In this case, for the given chemical reaction, we write the following law of mass action:
[tex]Keq=\frac{[N_2][O_2]}{[NO]^2}[/tex]
That in terms of the change [tex]x[/tex] due to the reaction extent (ICE procedure) we can write:
[tex]Keq=\frac{x*x}{([NO]_0-2x)^2}[/tex]
Thus, the initial concentration of nitrogen monoxide is:
[tex][NO]_0=\frac{0.570mol}{3.0L} =0.19M[/tex]
Thereby, we write:
[tex]2400=\frac{x*x}{(0.19-2x)^2}[/tex]
That we can solve by suing the quadratic equation formula or solver to obtain two roots:
[tex]x_1=0.094M\\x_2=0.096M[/tex]
Nevertheless, the correct answer is 0.094 M since the other root will produce a negative concentration of nitrogen monoxide at equilibrium, therefore, the equilibrium concentrations turn out:
[tex][N_2]_{eq}=x=0.094M[/tex]
[tex][O_2]_{eq}=x=0.094M[/tex]
[tex][NO]_{eq}=0.19M-2x=0.19M-2(0.094M)=0.002M[/tex]
Best regards.
7) Put the following molecules in order of where they would be found in the fractional distillation
column (from bottom to top). Hexane, Octane, Ethane, Dodecane, Decane, Methane
FAST
Answer:Crude oil is a mixture of many saturated hydrocarbons. They can be separated into fractions by the process of fractional distillation.
Explanation:
The graph below shows how the temperature and volume of a gas vary when the number of moles and the pressure of the gas are held constant. How can the volume of the gas be increased if the pressure is constant?
Answer:
Option C. By increasing the temperature
Explanation:
From the graphical illustration above, we see clearly that the volume and temperature of the gas are directly proportional. This implies that as the temperature increases, the volume will also increase and as the temperature decreases, the volume will also decrease. This can further be explained by using the ideal gas equation as shown below:
PV = nRT
P is the pressure.
V is the volume.
n is the number of mole.
R is the gas constant.
T is the temperature.
PV = nRT
Divide both side by P
V = nRT/P
Since n and P are constant, the equation above becomes:
V & T
V = KT
K is the constant.
The above equation i.e V = KT implies that:
As T increases, V will also increase and as T decreases, V will also decrease.
Considering the question given above,
The volume of the gas can be increased if the temperature is increased.
Who was the second person to organize the elements on the periodic table and what property did he use to re-organize them?
Answer:
Dmitri Mendeleev
Explanation:
He was a Russian Scientist who decided to reorganize the periodic table after other notable scientists such as Antoine-Laurent Lavoisier had also tried to organize it based on the states of matter of the elements.
Mendeleev reorganized the period in the order of increasing atomic mass although there were some other modifications by modern scientists.
The table below shows the similarity of Methane and water in molecular mass. They are also similar in both size and shape. Why does Methane exist in the gas state with a very low boiling point?
Answer:
Explanation:
In case of Water there are strong hydrogen boding excist as result shows high boiling point, wher as in case of methane the there is no hydrogen bond and excist weak vanderwall attraction between the molcuels so the lower boiling point.
An acid is added to water, and a new equilibrium is established. What is the system after the acid is added? A. pH w = 1 x 10-14 B. pH w -14 C. pH > pOH and Kw = 1 x 10-14 D. pH > pOH and Kw > 1 x 10-14
Answer:
C. pH > pOH; Kw = 1.0 * 10^-14
Explanation:
The ion product of water, Kw = [H+]*[OH-] = 1.0 * 10^-14. It is a constant.
When an acid or base is added to water, its ion product does not change as it a constant. However, the relative concentrations of H+ ions and OH- ions will change depending on whether an acid or base is added to water.
When an acid is added to water, the concentration of H+ ions increases while that of OH- ions decreases, and vice versa.
Therefore, in the above situation where an acid is added to water, pH > pOH; Kw = 1.0 * 10^-14
Two atoms bonded together will remain some distance apart, minimizing the Question 1 options: A) potential energy of the bond. B) bond distance. C) number of valence electrons in the bond. D) partial charge of the bond. Question 2 (5 points) BeH2 has no lone pairs of electrons. What's the structure of this molecule? Question 2 options: A) Tetrahedral B) Bent C) Octahedral D) Linear Question 3 (5 points) In KCl, how are the valence electrons distributed? Question 3 options: A) The electrons are transferred from K to Cl. B) The electrons are unequally shared between K and Cl, forming a polar covalent bond. C) The electrons are shared between many K and Cl ions, creating a "sea of electrons." D) The electrons are equally shared between K and Cl, forming a covalent bond. Question 4 (5 points) Chlorine can bond with fluorine to form ClF. Chlorine can also bond with lithium to form LiCl. Which compound will have a greater partial charge? Question 4 options: A) Both compounds will have the same partial charge. B) ClF C) LiCl D) Neither compound will have partial charge. Question 5 (5 points) Which of the following elements will not form a polar covalent bond with oxygen? Question 5 options: A) Hydrogen B) Oxygen C) Sodium D) Fluorine Which process is used to produce gases from solutions of salts dissolved in water or another liquid? Question 6 options: A) Electrolysis B) Polar covalent bonding C) Ionic bonding D) Metallic bonding Question 7 (5 points) Saved A chemical reaction has the equation AgNO3 (s) + NaCl (s) → AgCl (s) + NaNO3 (s). What type of reaction occurs between AgNO3 and NaCl? Question 7 options: A) Decomposition B) Double displacement C) Single displacement D) Synthesis
Answer:
1) potential energy of the bond.
2) Linear
3) The electrons are transferred from K to Cl.
4) ClF
5) Oxygen
6) Electrolysis
7) Double displacement
Explanation:
As two atoms approach each other in a bonding situation, the potential energy of the bond is minimized as the internuclear distance of the bonding atoms decreases.
BeH2 has two electron domains and the central beryllium atom is sp2 hybridized. According to valence shell electron pair repulsion theory. A molecule having two regions of electron density will lead to a linear molecule.
KCl is an ionic compound hence there is a transfer of electrons from K(metal) to Cl(nonmetal).
ClF has partial charges because it contains a polar covalent bond. The partial charges arise from the dipole within the molecule. LiF is a pure ionic compound formed by transfer of electrons from Li to F. The species possess full and not partial charges.
When an oxygen atom bonds with another oxygen atom, what has been formed is a homonuclear covalent bond. Since the electro negativity of the both atoms is exactly the same, a pure covalent bond is formed. Recall that polar covalent bonds are formed when there is a significant electro negativity difference between the bonding atoms.
When direct current is passed through certain salt solutions during electrolysis, gases may be evolved and collected at the appropriate electrodes.
A double-replacement reaction is a reaction in which the cations and anions present in two different ionic compounds that are reacting together exchange their positions to form two new compounds on the product side. For instance, look at the reaction shown in question 7 as a typical example of this;
AgNO3 (s) + NaCl (s) → AgCl (s) + NaNO3 (s).
(c)
Suggest a reason why substance E does not conduct electricity in both solid and
molten states.
Answer:
Substance E does not conduct electricity in both solid and molten states because of very low melting and boiling points.
In both solid and molten state free electrons are required to conduct electricity. substance E has low boiling and melting point which means substance will have relatively weak bonds. Because of weak bonds substance E might not have much free electron in its outermost shell that can cause the electric current by their coordinated movement.
Hence, substance E is unable to conduct in both melting and molten state.
Explain why covering something with a blanket can put out a fire
Answer:
No oxygen
Explanation:
when something is covered in a blanket it prevents the fire from being able to have any oxygen
Answer:
Its called smothering the fire
Explanation:
A fire needs three things to burn always: fuel, oxygen, and a heat source. Eventually the heat source will not be an issue, but the oxygen and fuel is. If the fire is small enough throwing a blanket can quite smother it. What happens is it cuts off the oxygen supply the fire needs long enough for it to die out.
What does the VSEPR theory predict?
A. The chemical formula of a molecule
B. The size of a molecule
C. The shape of a molecule
D. The charge of a molecule
Answer: C
Explanation:
A P E X
The VSEPR theory predicts the shape and molecular geometry of the molecule.
What is molecular geometry?Molecular geometry can be defined as a three -dimensional arrangement of atoms which constitute the molecule.It includes parameters like bond length,bond angle and torsional angles.
It influences many properties of molecules like reactivity,polarity color,magnetism .The molecular geometry can be determined by various spectroscopic methods and diffraction methods , some of which are infrared,microwave and Raman spectroscopy.
They provide information about geometry by taking into considerations the vibrational and rotational absorbance of a substance.Neutron and electron diffraction techniques provide information about the distance between nuclei and electron density.
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A 20 mL volume of a hydrochloric acid solution, HCl (aq), was placed into a beaker containing an appropriate
acid-base indicator. It was titrated with a solution of sodium hydroxide, NaOH (aq), until the endpoint was
reached. If 25 mL of sodium hydroxide solution with a concentration of 0.20 mol/L was used, what is the
concentration of the acid?
Select one:
a. 2.5 mol/L
O
b. 0.20 mol/L
C. 0.25 mol/L
d. 2.0 mol/L
Answer:
C- 0.25mol/L
Explanation:
Hcl+Naoh-Nacl+H2O
Ratio =1:1
0.2moles of Naoh in1000cm3 what about 25=(25×0.2)÷1000=
0.005moles
0.005moles in 20cm³ what about in 1000
(0.005×1000)÷20=0.25mol/L
According to the molar concentration, the concentration of the acid is 2.5 mole/liters.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.In case of 2 solutions, molar concentration is obtained as M₁V₁=M₂V₂, on substitution of values, M₁=25×0.20/20=2.5 mole/L.
Thus,the concentration of the acid is 2.5 mole/liters.
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What is the mass number of an atom that contains 19 protons, 19 electrons, and 20 neutrons?
Answer:
39
Explanation:
Total protons + total neutrons = mass number
HELP!!!!!!!!!!!!!!!! PRETTY PLEASE !!!!!!!!!!!!!!!!
Answer:
B. 75.0 kPa
Explanation:
P1V1/T1=P2V2/T2
(x * 100 L)/(300 K)=(100 kPa * 50.0 L)/(200 K)
x=75.0 kPa
Answer:
24rq3r54
Explanation:
3t5q6tq6tq
What volume will be occupied by 11.7 g of Helium in a balloon at an altitude of 10.0 km if the air pressure is 0.262 atm and the temperature is -50.0 °C?
Answer: 204 L
Explanation:
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 0.262 atm
V = Volume of gas = ?
n = number of moles = [tex]\frac{\text {given mass}}{\text {molar mass}}=\frac{11.7g}{4g/mol}=2.92[/tex]
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature =[tex]-50^0C=(273+(-50))K=223K[/tex]
[tex]V=\frac{nRT}{P}[/tex]
[tex]V=\frac{2.92\times 0.0820 L atm/K mol\times 223K}{0.262atm}=204L[/tex]
Thus volume occupied by 11.7 g of Helium in a balloon is 204L
How are the particles in solid ice similar to the particles in liquid water, and water vapor? How are they different?
Matter are anything that is made up of atoms. The similarity among solid ice, liquid water and water vapor is the water molecule and dissimilarities is the difference in kinetic energy.
What is matter?Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.
The similarity in the in the particles of solid ice, liquid water and water vapor is that each of these have same type of molecules that is water molecules. The dissimilarities in the in the particles of solid ice, liquid water and water vapor is that particles of of each of these have different kinetic energy.
Therefore, similarity among solid ice, liquid water and water vapor is the water molecule and disimilarity is the difference in kinetic eneergy.
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A simple experiment to demonstrate that NaOH is a stronger alkali than NH3
Answer:
pH value test can be used to demonstrate that NaOH is a stronger alkali than NH3
Explanation:
pH value test can be used to demonstrate that NaOH is a stronger alkali than NH3. This is done by measuring the same volume of equal concentration of hydroxide and ammonia. A glass rod was dipped into 0.2 M of sodium hydroxide and 0.2 M of ammonia, each drop of solution was then placed on a pH paper matched with a color chart and the pH value was recorded.
The result showed that sodium hydroxide being a strong alkali would dissociate completely in aqueous solution thereby having a higher pH while ammonia would dissociate slightly/partially in aqueous solution thereby having a lower pH value
The three states of matter can be arranged in the increasing order of interparticle forces as 1) gas > liquid >solid 2) solid >liquid > gas 3) liquid > gas > solid pls answer fast
Answer:
OPTION 2 SOLID>LIQUID>GAS
Explanation:
because the inter molecular forces are the strongest in the solid than in liquid and than in gas
Does the number of ions in solution increase, decrease, or remain constant?
It decreases at first, then increases.
It continuously increases.
It continuously decreases.
It increases at first, then decreases.
Answer:
It continuously decreases.
1.Mitch weighs out 67 grams of potassium (K) to make a buffer. How many moles of potassium did Dr. Hellman weigh out?
2.Which statement is NOT true about a reaction rate?
Group of answer choices
Increases with increase in reactant concentration
Increases with increasing temperature
Is the speed at which product is formed
Is the rate at which reactant is used up
All of the answers are true
3.Which statement is NOT true about a catalyst?
Group of answer choices
Are not used up during a reaction
Increases the rate of the reaction
Lowers the energy of activation
Biological catalysts are called enzymes
Are used up during a reaction
Answer:
1. 1.72 moles of potassium.
2. All of the answers are true
3. Are used up during a reaction
Explanation:
Recall that the number of moles is obtained from;
Number of moles= Mass of potassium/ molar mass of potassium
Mass of potassium= 67 g
Molar mass of potassium= 39 gmol-1
Number of moles of K= 67 g/ 39 gmol-1
Number of moles = 1.72 moles of potassium.
2. When we look at all the options, we will realize that all the options are true. The rate of reaction doubles for each 10°C rise in temperature, increasing reactant concentration increases particle collision and ultimately increases the rate of reaction. Rate of reaction deals with rate of disappearance of reactants or rate of appearance of products.
3. Catalysts remain unchanged in a chemical reaction because they do not actually participate in the reaction. Hence they are not used up in any chemical reaction.
Describe the differences seen in the properties of Boron and Nitrogen.
Answer:
Explanation:
As you move from left to right in periodic table the size of atom size decreases, electrongeativity increases.
it mean
Boron is bigger in size than Nitrogen
Boron is less electroneagive than Nitrogen.
can you find simialr to this another factor to realte
A 15.50 gram sample of a gas exerts a pressure of 1.40 atmospheres when held in an 8.00 liter at 22 °C. What is the molar mass (grams/mol) of the gas?
Answer:
33.5 g/mol
Explanation:
PV=nRT
(1.40 atm)(8.00 L)=n(0.08206)(295 K)
n=0.463 mol
15.50 g/0.463 mol=33.5 g/mol
The oxide of element X is reduced by heating with carbon.Element X does not react with cold water, steam or dilute hydrochloric acid.What is X?
The question is incomplete, the complete question is;
The oxide of element X is reduced by heating with carbon.
Element X does not react with cold water, steam or dilute hydrochloric acid.
What is X?
A copper
B iron
C magnesium
D zinc
Answer:
Copper
Explanation:
Copper is below hydrogen in the activity series of metals. Remember that the activity series of metals is an arrangement of metals in order of decreasing reactivity from most reactive to least reactive. The metals at the head of the series are highly reactive, metals at the middle of the series are moderately reactive while metals below hydrogen in the series are least reactive.
Copper being below hydrogen in the series cannot displace it from water (cold or steam) or from dilute acid solutions. Copper can be reduced by heating it with carbon (thermal reduction).
A balloon has a volume of 10,500 liters, and the temperature is 15°C. If the temperature were -25°C, what would the volume of the balloon be?
12,194 L
9,042 L
12,194 L is the answer!
Explanation:
Water has the maximum density at the temperature of 4°Celsius. So, it expands at temperatures higher or lower than 4°C, knowing that at the temperature of -25°C the water can't have a lower volume than the one at 15°C.
Answer:
12, 194 L
That's your answer!!!
boron has two naturally occurring isotopes .there are 10 b(20%)and 11b(80%).what is the average atomic mass of boron
Answer:
Explanation:
Average Atomic mass of any element =[ ∑ Abundance* mass of element] /100
= 10*20 +11*80 /100
= .........
Hope this helps you
Why does the presence of lone pairs contribute to the polarity of a water molecule
Explanation:
They allow the bonds between oxygen and hydrogen to be single. They increase the partial positive charge on the oxygen atom. They counter the uneven pull on electrons between the atoms.
Which of the following is an example of frontier research?
A. Investigating how organisms are made of cells.
B. Testing the electrical resistance of different materials.
C. Discovering the nature of dark matter.
D. Researching how animals on the Great Plains interact.
Answer:
B. Testing the electrical resistance of different materials.
Explanation:
An example of frontier research is " Testing the electrical resistance of different materials".
What is frontier research?A frontiers Research Topic offers researchers the chance to present various viewpoints, approaches, and findings on a new or developing topic in a forum monitored by experts in the area but also published in a complete open-access journal.
What is electrical resistance?Electrical resistance towards the current stream within an electrical circuit is measured by resistance. The Greek letter omega (ω) stands for ohms, which are used to evaluate resistance.
Therefore, the correct answer will be an option (B).
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CHEM HELP PLEASE
a reaction that has been calculated to produce 346 g of CH3OH actually produced 312 g of CH3OH. what is it's percent yield?
Answer:
90.2%
Explanation:
% yield = actual yield/ theoretical yield * 100%
% yield = (312/346)*100% = 90.2%
