Answer:
D
Explanation:
Elements in the same group (vertical columns) have the same number of valence electrons. These elements behave similarly because they will either give up or take the same number of electrons to fill their valence shell. Since potassium has 1 valence electron, it will most likely give up one electron. Out of all of the answer options, the only element that is in the same group as potassium is francium.
Answer:
D. Francium (Fr)
Explanation:
Just did it!!
Antifreeze is added to a car's radiator to protect it. Which of the following
facts about the use of antifreeze illustrates a rule that governs the physical
world?
A. Car radiators use water to cool the engine.
B. Antifreeze protects the radiator during summer and winter.
C. Car radiators can freeze in the winter and boil over in the summer
D. Antifreeze keeps water from freezing when it is cold out.
Answer:
the correct answer is b antifreeze protects the radiator during summer in winter.
Explanation:
Antifreeze is (typically mixed with water) to help manage the engine during extreme temperatures. As the temperature fluctuates between hot and cold coolant is distributed throughout the engine block to sustain even operating temperature.
The reaction of pyrrole with bromine forms predominantly __________. View Available Hint(s) The reaction of pyrrole with bromine forms predominantly __________. 2-bromopyrrole 2,3-dibromopyrrole N-bromopyrrole 3-bromopyrrole
Answer:
a) 2-bromopyrrole
Explanation:
Our options for this questions are:
a) 2-bromopyrrole
b) 2,3-dibromopyrrole
c) N-bromopyrrole
d) 3-bromopyrrole
To understand how the reaction works we have to start with the resonance structures. (Figure 1), on these structures, we will obtain a negative charge on carbon 2 in the pyrrole ring, therefore on this carbon we can generate an attack to an electrophile.
The second step is to check how the mechanism take place. An electrophile is generated by the [tex]Br_2[/tex] and [tex]FeBr_3[/tex]. This electrophile can be attacked by the negative charge on carbon 2 producing the 2-bromopyrrole. (See figure 2).
I hope it helps!
To condition the buret, add a small volume of ____________ to the buret and rotate the barrel ____________ so that the liquid makes contact with the full inner surface of the barrel. Complete this action _________ and discard each volume in a designated waste container.
Answer:
Acid, Horizontally, Drain off the acid by opening the stopcock
Explanation:
A buret is a calibrated glass appratus used to measure and deliver accurate volume of liquid, usually acids, in acid-base titrations.
Before usually the buret to carry out your titration reaction, it is advised to condition or prepare your buret for use.
To condition the buret, add a small volume of the acid to the buret and rotate the barrel horizontally to ensure that the liquid ( acid) makes contact with the inner surface of the barrel o the buret.
This procedure is done to wash off any previous acid or liquid that the buret had been used for in previous titrations.
Complete this action by opening the stopcock of the buret to drain off the acid and discarding each volume in a designated waste container.
Note that acids could be corrosive and dangerous to the skin and so should be handled with great care
A sample of a pure compound that weighs 59.8 g contains 27.6 g Sb (antimony) and 32.2 g F (fluorine). What is the percent composition of fluorine
Answer:
53.85%
Explanation:
Data obtained from the question include:
Mass of antimony (Sb) = 27.6g
Mass of Fluorine (F) = 32.2g
Mass of compound = 59.8g
Percentage composition of fluorine (F) =..?
The percentage composition of fluorine can be obtained as follow:
Percentage composition of fluorine = mass of fluorine/mass of compound x 100
Percentage composition of fluorine = 32.2/59.8 x 100
= 53.85%
Therefore, the percentage composition of fluorine in the compound is 53.85%
If 852.04 g Al(NO3)3 reacted with the 741.93 g Na2CO3, which would be the limiting reagent?
Answer:
Al(NO3)3
Explanation:
A chemical reaction produces products based on the moles of the reactants. Aluminum nitrate will be the limiting reagent in the reaction with sodium carbonate.
What is a limiting reagent?A limiting reagent defines the reactants that get consumed sooner than the other reactant and determines the product formation in a chemical reaction. Unlike excess reagents, they do not remain unconsumed in a reaction.
The limiting reagent can be determined by the reaction as,
2 Al(NO₃)₃ + 3 Na₂CO₃ → Al₂(CO₃)₃ + 6NaNO₃
From the reactions, there are 2 moles of aluminum nitrate and 3 moles of sodium carbonate. So, if 852.04 g aluminum nitrate reacts with 741.93 g sodium carbonate then Al(NO₃)₃ will be the limiting reagent as it has less number of moles compared to Na₂CO₃ and will be consumed first.
Therefore, aluminum nitrate will be the limiting reagent.
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A single atom of an element has 11 protons, 11 electrons, and 12 neutrons. Which element is it?
V
Na
ООО
Mg
Se
Answer:
Na
Explanation:
When identifying elements, you only need to look at the number of protons. Elements can have varying numbers of electrons and neutrons, but they can only have one number of protons.
Looking at the periodic table, the elements with 11 protons is sodium (Na).
Answer:
Na
Explanation:
The half-life of carbon-14 is 5,730 years. An artifact produces 8.8 disintegrations of 14C per minute per gram of carbon in the sample. Estimate the age of this sample assuming that its original radioactivity was 15.3 disintegrations per minute per gram of carbon.
Answer:
Approximately 4574.86 years
Explanation:
Hello,
To find the age of this sample, we should first of all convert the disintegration per minute to per year so that we can work on the same unit as our half life (T½), then we can find the disintegration constant and use it to find the year of the artifact.
Data;
T½ = 5730 years
Initial rate of radioactivity (No) = 15.3 disintegration per minute.
Current rate of radioactivity (N) = 8.8 disintegration per minute.
1 year = 525600 minutes
1 mins = 8.8 disintegration
525600mins = N disintegration
N = (525600 × 8.8) / 1
N = 4625280
1 mins = 15.3 disintegration
525600 mins = No
No = 8041680
But T½ = In2 / λ
λ = In2 / T½
λ = 0.693 / 5730
λ = 1.209×10⁻⁴ (this is the disintegration constant)
We can now find the how old the artifact is using our disintegration constant and other parameters.
In(N÷No) = -λt
In[4625280 / 8041680] = -(1.209×10⁻⁴ × t)
In[0.57516] = -1.209×10⁻⁴t
-0.5531 = -1.209×10⁻⁴ t
Solve for t
t = 0.5531 / 1.209×10⁻⁴
t = 4574.86 years
The artifact is approximately 4574.86 years
what volume(in dm³) of 0.30 moldm-³ Nacl solution can be prepared from 0.060mol of solute?
Answer:
0.2 dm³
Explanation:
Concentration = no. of moles of solute / volume
Concentration: 0.30 mol dm-³
no. of moles of solute: 0.060mol
0.3 = 0.06 / v
v = 0.2 dm³
The volume(in dm³) of 0.30 moldm-³ Nacl solution can be prepared from 0.060mol of solute is 0.2 dm³.
What is volume?Volume is the space occupied by a three-dimensional object. A mixture of two or more components is referred to as a solution.
A solute in these combinations is a substance that dissolves in a solvent, which is a different substance.
Nacl is a common salt used in daily basis for cooking purpose.
Given, the 0.30 moldm-³ Nacl solution
Solute is 0.060mol
Concentration = no. of moles of solute divided by the volume of the Nacl solution.
Concentration is 0.30 mol dm-³
No. of moles of solute is 0.060mol
0.3 = 0.06 / v
The volume = 0.2 dm³
Therefore, the volume(in dm³) of 0.30 moldm-³ Nacl solution can be prepared from 0.060mol of solute is 0.2 dm³.
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Given the following equilibrium constants:
Na2O(s) ⇌ 2 Na(l) + 1/2 O2(g) K1= 2 x 10^–25
NaO(g) ⇌ Na(l) + 1/2 O2(g) K2= 2 x 10^–5
Na2O2(s) ⇌ 2 Na(l) + O2(g) K3= 5 x 10^–29
NaO2(s) ⇌ Na(l) + O2(g) K4= 3 x 10^–14
Determine the value for the equilibrium constants for the following reaction:
2 NaO(g) ⇌ Na2O2(s)
Answer:
K = 8x10¹⁸
Explanation:
When you sum a reaction, the result of this sum has a K equal to the multiplication of the K's of the reactions involved in the sum
The sum of two times the reaction:
NaO(g) ⇌ Na(l) + 1/2 O₂(g) K₂ = 2x10⁻⁵
2 NaO(g) ⇌ 2 Na(l) + O₂(g) K = K₂ₓK₂ = (2x10⁻⁵)² = 4x10⁻¹⁰
The result of the inverse reaction:
Na₂O₂(s) ⇌ 2 Na(l) + O₂(g) K₃= 5x10⁻²⁹
2 Na(l) + O₂(g) ⇌ Na₂O₂(s) K = 1/K₃ = 2x10²⁸
And the sum of the two bolded reactions:
2 NaO(g) + 2 Na(l) + O₂(g) ⇌ 2 Na(l) + O₂(g) + Na₂O₂(s)
2 NaO(g) ⇌ Na₂O₂(s) K = 4x10⁻¹⁰× 2x10²⁸
K = 8x10¹⁸
How did the Bohr model of the atom affect scientific thought?
A. Scientists accepted Bohr's model as a useful explanation
B. Scientists rejected the model because it didn't fit the data
C. Scientists accepted the model at first, but later rejected it.
D. Scientists finally agreed that Bohr's model was accurate,
Answer:
C. Scientists accepted the model at first but later rejected it.
Explanation:
Scientists accepted the model at first because it explained the hydrogen emission spectrum.
However, with the development of quantum mechanics, scientists had to modify the model (not reject it).
Electrons still had specific energies, but they no longer travelled in fixed orbits.
Instead, electrons had a probability of being found in a given region of space.
Scientists accepted the model at first but later rejected it.
How did Bohr change science?Niels Bohr change the atomic theory by realizing that the electrons did not crash into the nucleus as would be expected in classical physics. Classical physics says that opposites attract and like to repel, so the negative electrons should be attracted to the positive nucleus.
What did Bohr contribute to modern theory?In 1913, Niels Bohr proposed a theory for the hydrogen atom, based on quantum theory that some physical quantities only take discrete values. Electrons move around a nucleus, but only in prescribed orbits, and If electrons jump to a lower-energy orbit, the difference is sent out as radiation.
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Write the empirical formula
Answer:
[tex]Fe(C_{2}H_{3}O_{2})_{3}\\Fe (OH)_{3}\\\\NH_{4}(C_{2}H_{3}O_{2})\\\\NH_{4}OH[/tex]
Explanation:
[tex]Fe^{3+}(C_{2}H_{3}O_{2})^{-}_{3}--->Fe(C_{2}H_{3}O_{2})_{3}\\Fe^{3+} (OH^{-})_{3}--->Fe (OH)_{3}\\\\NH_{4}^{+}(C_{2}H_{3}O_{2})^{-}--->NH_{4}(C_{2}H_{3}O_{2})\\\\NH_{4}^{+}OH^{-} ---> NH_{4}OH[/tex]
What is the number of Cl atoms in a 784 gram pure sample of NC13?
Answer:
idk
Explanation:
idk cool pee bee mee nee hee gee fee kee
In a 784 gram pure sample of NC13, there are approximately 1.33 x 10²⁵ chlorine atoms.
To determine the number of chlorine (Cl) atoms in a given sample, we need to utilize the Avogadro's number and the molar mass of chlorine.
The molar mass of chlorine (Cl) is approximately 35.45 grams/mol. To calculate the number of moles in the sample, we divide the given mass by the molar mass:
Number of moles of Cl = Mass / Molar mass
Number of moles of Cl = 784 g / 35.45 g/mol
Number of moles of Cl ≈ 22.08 mol
According to Avogadro's number, there are 6.022 x 10²³ entities (atoms, molecules, or formula units) in 1 mole of a substance. Therefore, to find the number of chlorine atoms, we multiply the number of moles by Avogadro's number:
Number of Cl atoms = Number of moles of Cl x Avogadro's number
Number of Cl atoms = 22.08 mol x 6.022 x 10²³ atoms/mol
Number of Cl atoms ≈ 1.33 x 10²⁵ atoms
Therefore, in a 784 gram pure sample of NC13, there are approximately 1.33 x 10²⁵ chlorine atoms.
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can someone assist me with this chemistry question please?
Answer:
490 J.
Explanation:
The following data were obtained from the question:
Mass (m) = 5 Kg
Height (h) = 10 m
Acceleration due to gravity (g) = 9.8 m/s²
Potential energy (P.E) =..?
Potential energy is the energy stored in a body by virtue of its location. Mathematically, it can be expressed as:
P.E = mgh
Where:
m is the mass of the object measured in kilograms (Kg).
g is the acceleration due to gravity and the value is 9.8 m/s².
h is the height to which the object is located measured in metre (m)
P.E is the potential energy measured in joule (J).
With the above formula, we can obtain the potential energy possed by the object as follow:
P.E = mgh
P.E = 5 x 9.8 x 10
P.E = 490 J
The,the potential energy possed by the object is 490 J
Consider 1 M solutions of NaCl, ethyl alcohol (CH3CH2OH), and hydrofluoric acid. Rank them in terms of how well they conduct electricity and explain why you ranked them this way.
Answer:
conductivity increasing order CH₃-CH₂-OH < HF< NaCl
Explanation:
NaCl is the better conductor comparing with remaining two. it is strong electrolyte. dissociation percent always nearly eqaul to 100% but HF is weaker acid than NaCl and dissociation percent <100% . So, the no of ions furnished by HF less than that of NaCl
CH₃-CH₂-OH organic compound . in general it is not treated as an electrolyte and it cannot carry any charge. If it carries, it is very very less compared to remaining two
What is the temperature of 0.420 mol of gas at a pressure of 1.5 atm and a volume of 11.2 L?
Answer:
R = 0.08206L atm mol-1K-1
pv = nRT1.5 x 11.2 = 0.420 x0.08206 xT16.8 = 0.0345 xTT =16.8/0.0345T = 486.96KT = 213°CAn analytical chemist is titrating of a solution of nitrous acid with a solution of . The of nitrous acid is . Calculate the pH of the acid solution a
Answer:
pH = 2.69
Explanation:
The complete question is: An analytical chemist is titrating 182.2 mL of a 1.200 M solution of nitrous acid (HNO2) with a solution of 0.8400 M KOH. The pKa of nitrous acid is 3.35. Calculate the pH of the acid solution after the chemist has added 46.44 mL of the KOH solution to it.
The reaction of HNO₂ with KOH is:
HNO₂ + KOH → NO₂⁻ + H₂O + K⁺
Moles of HNO₂ and KOH that react are:
HNO₂ = 0.1822L × (1.200mol / L) = 0.21864 moles HNO₂
KOH = 0.04644L × (0.8400mol / L) = 0.0390 moles KOH
That means after the reaction, moles of HNO₂ and NO₂⁻ after the reaction are:
NO₂⁻ = 0.03900 moles KOH = moles NO₂⁻
HNO₂ = 0.21864 moles HNO₂ - 0.03900 moles = 0.17964 moles HNO₂
It is possible to find the pH of this buffer (Mixture of a weak acid, HNO₂ with the conjugate base, NO₂⁻), using H-H equation for this system:
pH = pKa + log₁₀ [NO₂⁻] / [HNO₂]
pH = 3.35 + log₁₀ [0.03900mol] / [0.17964mol]
pH = 2.69Suppose a system of two particles, represented by circles, have the possibility of occupying energy states with 0, 10, or 20 J. Collectively, the particles must have 20 J of total energy. Are there any other energetically equivalent configurations?
Answer:
Explanation:
The possible energy states for the particles are 0, 10 and 20 J.
The constraint in the system is that the total energy of the particles must be 20 J.
One given configuration where the total energy is 20 J is if both the particles occupy the 10 J state.
Hence, (10;10) is the given configuration.
Another possibility is if one of the particle is in 0 J state and another is in 20 J state. Hence, the system has a total energy of 0+20 = 20 J.
Hence, the possible configuration can be written as (0;20) or (20;0) which are energetically equivalent to the given configuration. Note that if the circles are indistinguishable, then the configuration (0,20) and (20,0) is the same thing.
A solution contains 221 g of glycerol (C3H8O3) in 600 grams of water. For the solvent the Kf is 1.86 °C m-1 and Kb is 0.51 °C m-1. What should the boiling point of the solution be?
Answer:
the boiling point of the solution = 106.12 °C
Explanation:
What does light do in the photoelectric effect?
O A. Light turns metal into electricity.
B. Light knocks electrons off metal atoms.
C. Light reacts with metal atoms.
D. Light is turned into electricity by the metal.
Answer:
it's B: light knocks electrons off metal atoms
Which three events occur when earths convection currents move toward each ither
Answer:
- tectonic plates above the currents move toward each other
- one plate will submerge beneath another plate
- a convergent boundary is formed at the site of the collision
Explanation:
Identify the following substances:
(1) An acidic gas which gives dense white fumes with NH3
(11 An alkane which can also be called a green house gas.
(iii) A solid which when kept in the open, forms a solution after som
(iv) An alloy used in electrical fittings.
(v) A metal which gives hydrogen gas on reacting with both dilute a
Write equations for the following reactions:
Aluminium oxide and Sodium hydroxide.
(ii) Zine and dilute sulphuric acid.
(
11
Answer:
1) HCl (Hydrochloric acid reacts with NH3 and forms dense fumes)
2) Methane (It is from the group of alkanes and is a green house gas)
3) Deliquescent substance (It is a solid which when kept in open forms a solution after sometime)
4) Brass (It is a solid-in-solid solution used to make electrical fittings)
5) Aluminium
Question 2:
1) Al₂O₃ + 2NaOH ⇒ 2NaAlO₂ (Sodium Aluminate) + H₂O
2) Zn + H₂SO₄ (dilute) => ZnSO₄ (Zinc Sulphate) + H₂
Answer:
HCl is the gasmethanedeliquescent substances (they absorbs water out of the air until they dissolve themselves into liquid solutions. )brassequations
Aluminium oxide and Sodium hydroxide react to form water and sodium aluminate
Al2O3 + 2NaOH → 2NaAlO2 + H2OZinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas
Zn + H2SO4 → ZnSO4 +H2
What is the molecular formula of a compound that contains 10.0g carbon, 1.68g hydrogen, and 13.4g oxygen
Answer:
CH2O
Explanation:
(view this on a laptop to avoid the spacing problems)
We can draw a chart to solve this:
Carbon Hydrogen Oxygen
mass(g) 10.0 1.68 13.4
no. of moles 10/12 = 0.83333 1.68/1 = 1.68 13.4/16=0.8375
ratio 0.83333/0.83333=1 1.68/0.8333≈2 0.8375/0.83333≈1
(divide by the smallest no. of mole- which is carbon)
Therefore, the molecular formula is CH2O.
The following reaction is part of the electron transport chain. Complete the reaction and identify which species is reduced. The abbreviation Q represents coenzyme Q. Use the appropriate abbreviation for the product.
FADH2 + Q →
The reactant that is reduced is: _____
Answer:
[tex]FADH_2 + Q --> FAD + QH_2[/tex]
The reactant that is reduced is [tex]FADH_2[/tex]
Explanation:
The complete equation is as below:
[tex]FADH_2 + Q --> FAD + QH_2[/tex]
Recall that oxidation involves the gain of electrons while reduction involves the loss of electrons.
In the above reaction, [tex]FADH_2[/tex] loses electrons to coenzyme Q and becomes reduced to FAD, hence the oxidizing agent. Coenzyme Q gains electrons and becomes oxidized to [tex]QH_2[/tex] , hence the reducing agent.
In order words, [tex]FADH_2[/tex] is reduced while coenzyme Q is oxidized.
Question 3 (11 points)
A gas has a volume of 690.0mL at -15.1°C and 392.0 mmHg. What would the volume of the gas be at
233.0°C and 0.700 atm of pressure? Answer with no decimal places.
Answer:
V2 = 0.998L
v2 = 0.000998mL
Explanation:
P1 = 392mmHg
V1 = 690mL
T1 = -15.1°C = 257.9k
P2 = 0.700atm = 532mmHg
V2 = ?
T2 = 233°C = 506K
using general gas equation
P1V1/T1 = P2V2/T2
(392 x 690.0 x 10^-³)/257.9 =(532 x V2)/506
1.05=(532 x V2)/506
1.05 x 506 =(532 x V2)
531.3 =(532 x V2)
V2 = 531.3/532
V2 = 0.998L
v2 = 0.000998mL
Which part of the fuel cell does A represent?
O anode
O cathode
Identify the missing numbers for Oxygen (O) for "A" and "B" in the chart below. The first number in the answer selection represents "A", the second number in the answer selection represents "B."
A. 8, 8
B. 24, 16
C. 16, 16
D. 4, 8
Answer:
Option A. 8, 8
Explanation:
The following data were obtained from the question:
Proton number = 8
Atomic number = 8
Mass number = 16
A. Determination of the Neutron number. This can be obtain as follow:
Proton number = 8
Mass number = 16
Neutron number =.?
Mass number = Proton + Neutron
16 = 8 + Neutron
Collect like terms
Neutron = 16 – 8
Neutron = 8
B. Determination of electron number. This can be obtain as follow:
Since the atom is a neutral atom ( i.e O), the electron number is the same as the proton number. Therefore,
Electron = Proton = 8
Therefore,
A = 8 and B = 8
The solubility of nitrogen gas at 25°C and a nitrogen pressure of 522 mmHg is 4.7 × 10 –4 mol/L. What is the value of the Henry's Law constant in mol/L·atm?
Answer:
6.8 × 10⁻⁴ mol/L.atm
Explanation:
Step 1: Given data
Solubility of nitrogen gas at 25°C (S): 4.7 × 10⁻⁴ mol/L
Partial pressure of nitrogen gas (P): 522 mmHg
Step 2: Convert the partial pressure of nitrogen to atm
We will use the relationship 1 atm = 760 mmHg.
[tex]522mmHg \times \frac{1atm}{760mmHg} = 0.687atm[/tex]
Step 3: Calculate the value of the Henry's Law constant (k)
We will use Henry's law.
[tex]S = k \times P\\k = \frac{S}{P} = \frac{4.7 \times 10^{-4}mol/L }{0.687atm} = 6.8 \times 10^{-4} mol/L.atm[/tex]
An electrode has a negative electrode potential. Which statement is correct regarding the potential energy of an electron at this electrode?
A. An electron at this electrode has the same potential energy as it has at a standard hydrogen electrode.
B. An electron at this electrode has a lower potential energy than it has at a standard hydrogen electrode.
C. An electron at this electrode has a higher potential energy than it has at a standard hydrogen electrode.
Answer:
C. An electron at this electrode has a higher potential energy than it has at a standard hydrogen electrode.
Explanation:
The standard hydrogen electrode (SHE) is used to measure the electrode potential of substances. The standard hydrogen electrode is arbitrarily assigned an electrode potential of zero. Recall that electrode potentials are always measured as reduction potentials in electrochemical systems.
For an electrode that has a negative electrode potential, electrons at this electrode have a higher potential energy compared to electrons at the standard hydrogen electrode. Electrons flow from this electrode to the hydrogen electrode.
On the other hand, a positive electrode potential implies that an electron at this electrode has a lower potential energy than it has at a standard hydrogen electrode. Hence electrons will flow from the standard hydrogen electrode to this electrode.
If you combine 24.2 g of a solute that has a molar mass of 24.2 g/mol with 100.0 g of a solvent, what is the molality of the resulting solution
Answer: 10 moles/kg.
Explanation:
Given, Mass of solute = 24.2 g
Molar mass of solute = 24.2 g/mol
[tex]\text{Moles of solute =}\dfrac{\text{Mass of solute}}{\text{Molar mass of solute}}\\\\=\dfrac{24.2}{24.2}=1[/tex]
Mass of solvent = 100.0g = 0.1 kg [1 g=0.001 kg]
[tex]\text{Molality}=\dfrac{\text{Moles of solute}}{\text{kilograms of Solvent}}\\\\=\dfrac{1}{0.1}\\\\=10\ moles/kg[/tex]
Hence, the molality of the resulting solution is 10 moles/kg.
The solubility of carbon tetrachloride (CCl4) in water at 25 ∘C is 1.2 g/L. The solubility of chloroform (CHCl3) at the same temperature is 10.1 g/L. Why is chloroform almost 10 times more soluble in water than carbon tetrachloride?
Answer:
I WOULD ANSWER IT VERY SOON
Explanation: