Use the periodic table to answer the questions: Which is the correct electron configuration for sodium (Na)?
1s22s22p62d1
1s22s22p63s1
1s22p63d3
Answer: The correct answer is [tex]1s^22s^22p^63s^1[/tex]
Explanation:
Electronic configuration is defined as the configuration in which total number of electrons are represented which are present in an element.
Number of electrons are determined by the atomic number of that element.
Atomic number of Sodium = 11
Electronic configuration of sodium element (Na) : [tex]1s^22s^22p^63s^1[/tex]
Hence, the correct answer is [tex]1s^22s^22p^63s^1[/tex]
Tritium (31h) is an isotope of hydrogen that is sometimes used to make the hands of watches glow in the dark. the half-life of tritium is 12.3 years. after 49 years, approximately how much of the original tritium remains?
Answer:
6.31%
Explanation:
In order to solve this, you need to use the expression to calculate half life, which is the following:
C = Co e^-t λ (1)
Where:
C: concentration after t has passed
Co: initial concentration
t: time that has passed
λ: lambda which relation half life time
λ this can be calculated with the following expression:
λ = ln2 / t(1/2) (2)
So, let's calculate λ first and then, the concentration. In this case, we will assume that we begin with a concentration at 100%.
The value of lambda is:
λ = ln2 / 12.3
λ = 0.0564
Now, let's use (1) to calculate the concentration after 49 years:
C = 100 e^ (-49 * 0.0564)
C = 100 e^(-2.7636)
C = 6.31 %
And this will be the tritium remaining after 49 years
Which of the following is a natural cause of wildfires
Answer:
lightning
Explanation:
Natural fires are generally started by lightning, with a very small percentage started by spontaneous combustion of dry fuel such as sawdust and leaves. On the other hand, human-caused fires can be due to any number of reasons. Some classifications include smoking, recreation, equipment, and miscellaneous.
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In which substance does phosphorus have a +3 oxidation state
Phosphorus has a +3 oxidation state in tetraphosphorus hexaoxide (P4O6) and phosphorous acid (H3PO3).
Explanation:Phosphorus exhibits different oxidation states in various substances. When it comes to a +3 oxidation state, phosphorus(III) oxide, also known as tetraphosphorus hexaoxide (P4O6), is the substance where phosphorus has a +3 oxidation state. This compound can be formed when white phosphorus is carefully burned in limited oxygen. Additionally, another compound where phosphorus has a +3 oxidation state is phosphorous acid, H3PO3, which can be obtained by the slow dissolution of phosphorus(III) oxide in cold water.
Phosphorus also forms hydrides, such as diphosphorus tetrahydride (H2P-PH2) and tetraphosphorus trisulfide (P4S3), which exhibit phosphorus in atypical oxidation states including the +3 state.
What is the molarity of a salt solution that is made from 31.0 grams of ca3(po4)2 placed in a volumetric flask and filled to the 2 liter line with distilled water?
List the information you need to find how many milliliters of a stock solution of 2.00m mgso4 you would need to prepare 100.0 ml of 1.00m mgso4
To determine how many milliliters of a stock solution are needed to prepare a given volume of a diluted solution, one can use the dilution formula 'M1V1 = M2V2’. In this case, you'd need 50.0 ml of the stock solution to prepare 100.0 ml of a 1.00m MgSO4 solution.
Explanation:To find out how many milliliters of a stock solution of 2.00m MgSO4 you would need to prepare 100.0 ml of 1.00m MgSO4, you can use the formula M1V1 = M2V2, where M1 is the molarity of the initial solution, V1 is the volume of the initial solution, M2 is the molarity of the final solution, and V2 is the volume of the final solution.
Firstly, we substitute the given values into the formula. M1 is our initial molarity (2.00m), V1 is what we're trying to find, M2 is our final molarity (1.00m) and V2 is our final volume (100.0 ml). By rearranging the formula, we get V1 = (M2 * V2) / M1.
The calculation step becomes: V1 = (1.00m * 100.0 ml) / 2.00m = 50.0 ml. Therefore, you would need 50.0 milliliters of the stock solution to prepare 100.0 ml of a 1.00m MgSO4 solution.
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What volume of 0.45 M LiOH would be needed to neutralize 60.0 mL of 0.15 M Hi?
To neutralize 60.0 mL of 0.15 M HCl, 20.0 mL of 0.45 M LiOH is required. The neutralization reaction proceeds in a 1:1 molar ratio.
Explanation:To calculate the volume of 0.45 M LiOH required to neutralize 60.0 mL of 0.15 M HCl, we use the neutralization reaction where LiOH reacts with HCl in a 1:1 molar ratio:
LiOH + HCl → LiCl + H2OFirst, calculate the number of moles of HCl:
moles HCl = volume (L) × molarity (M) = 0.060 L × 0.15 M = 0.009 moles
Since the molar ratio is 1:1, 0.009 moles of LiOH will also be needed.
Then, calculate the volume of LiOH solution:
Volume LiOH = moles LiOH / molarity of LiOH = 0.009 moles / 0.45 M = 0.020 L or 20.0 mL
Therefore, 20.0 mL of 0.45 M LiOH is required to neutralize 60.0 mL of 0.15 M HCl.
If 72.0 grams of aluminum are reacted with 252 grams of hydrochloric acid, how many grams of aluminum chloride are produced by this reaction? 2al(s) + 6hcl(aq) → 2alcl3(aq) + 3h2(g)
Final answer:
To determine the grams of aluminum chloride produced in the reaction, use the given balanced chemical equation and the molar masses of aluminum and aluminum chloride. Convert the given masses of aluminum and hydrochloric acid to moles and use the stoichiometric ratios to determine the moles of aluminum chloride produced. Finally, convert the moles of aluminum chloride to grams.
Explanation:
To determine the grams of aluminum chloride produced in the reaction, we need to use the given balanced chemical equation and the molar masses of aluminum (Al) and aluminum chloride (AlCl3). The molar mass of Al is approximately 26.98 g/mol, while the molar mass of AlCl3 is approximately 133.34 g/mol.
First, we convert the given masses of aluminum (72.0 g) and hydrochloric acid (252 g) to moles using their respective molar masses. Using the ratios from the balanced chemical equation, we can then determine the moles of aluminum chloride produced.
Starting with 72.0 g of Al:
72.0 g Al * (1 mol Al / 26.98 g Al) * (2 mol AlCl3 / 2 mol Al) * (133.34 g AlCl3 / 1 mol AlCl3) = 398.908 g AlCl3
Therefore, approximately 398.908 grams of aluminum chloride are produced.
Which of the space missions involved the deployment of lunar rover
A. Voyager 1
B. Gemini
C. Mercury
D. Apollo
Please help asap on clock
Answer:
The answer is D.Apollo
Explanation:
The statement that describes the space missions involved the deployment of lunar rover is "Apollo."
What is a space mission?
A space mission is defined as the act of sending a space item to its designated location and then performing scientific or technological operations there. An examination of the reaches of the universe beyond Earth's atmosphere using crewed and uncrewed spacecraft, with the goal of increasing understanding of the cosmos and benefiting humanity.
The majority of the deployment occurred automatically as the rover was released from the bay.
The lunar rovers of Apollo 15, 16, and 17 anchored American automotive culture on the moon's surface while broadening the scientific scope of the missions' astronaut explorers.
Hence the correct option is Apollo.
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Question 4 if 0.587 g of nickel metal reacts with 1.065 g of chlorine gas, what is the empirical formula of the nickel chloride product? ni2cl3 ni3cl2 nicl3 nicl nicl2
The empirical formula of nickel chloride, given the masses of nickel and chlorine, is c) NiCl₃
Determining the Empirical Formula of Nickel Chloride
To determine the empirical formula of nickel chloride from the given masses of nickel (0.587 g) and chlorine (1.065 g), follow these steps:
Convert the mass of each element to moles:
Nickel (Ni): 0.587 g ÷ 58.69 g/mol = 0.0100 mol
Chlorine (Cl): 1.065 g ÷ 35.45 g/mol = 0.0300 mol
Determine the simplest whole number ratio:
Nickel: 0.0100 mol ÷ 0.0100 mol = 1
Chlorine: 0.0300 mol ÷ 0.0100 mol = 3
Write the empirical formula: Hence, the simplest ratio of Nickel to Chlorine is 1:3, making the empirical formula NiCl₃
Which of the following is NOT true about "yield"? a. The value of the actual yield must be given in order for the percent yield to be calculated. b. The percent yield is the ratio of the actual yield to the theoretical yield. c. The actual yield may be different from the theoretical yield because reactions do not always go to completion. d. The actual yield may be different from the theoretical yield because insufficient limiting reagent was used.
All the provided statements about 'yield' in chemistry are correct. The yield represents the amount of product from a chemical reaction. Percent yield is calculated using actual and theoretical yields, which can differ due to incomplete reactions or limiting reagents.
Explanation:Regarding your question about which statement is not true about 'yield', all of the statements you listed are generally correct. Yield in chemistry refers to the amount of product obtained in a chemical reaction. The theoretical yield is the maximum possible amount of product that can be produced from a given amount of reactants. The actual yield is the amount of product actually produced when the chemical reaction is carried out in an experiment.
The percent yield is the ratio of the actual yield to the theoretical yield, expressed as a percentage (statement b). This value indeed requires knowledge of the actual yield (statement a). Both the actual and theoretical yield can differ due to incomplete reaction or inefficient use of limiting reagents (statement c and d).
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To find the number of protons, neutrons, and electrons in a particular atom, you must know the mass number and the atomic number of the atom
Silver nitrate (AgNO3) reacts with hydrochloric acid (HCl) to produce nitric acid (HNO3) and silver chloride (AgCl). AgNO3 + HCl HNO3 + AgCl Which of the following actions would increase the reaction rate? A. increasing the concentration of HCl B. decreasing the concentration of AgCl C. decreasing the concentration of AgNO3 D. increasing the concentration of HNO3
Silver nitrate (AgNO₃) reacts with hydrochloric acid (HCl) to produce nitric acid (HNO₃) and silver chloride (AgCl). Increasing the concentration of HCl would increase the rate of reaction and the correct option is option A.
The rate of reaction or reaction rate is the speed at which reactants are converted into products. It is the measure of the change in concentration of the reactants or the change in concentration of the products per unit time. If a reaction has a low rate, that means the molecules combine at a slower speed than a reaction with a high rate.
Factors influencing the rate of reaction are:
1. surface area of a solid reactant
2. concentration and pressure of a reactant
3. temperature
4. nature of reactants
5. presence/absence of a catalyst
Thus, the ideal selection is option A.
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Indentify two advantages in daylight saving time
Which energy source has been developed and improved by chemists?
Answer:Explained
Explanation:
The following energy has been developed and improved by chemists
Nuclear energy coal gasgasolineEthanolKerosene PropaneAnything which includes chemical reaction has been developed by chemists to utilize the hidden energy.For example Nuclear energy
If proper reactions and controlled environment is given then a huge amount of energy can be generated from Radioactive elements.
How many moles of ions are produced by the dissociation of 1 mol of al2(co3)3?
The moles of ions produced are 5.
What are moles?The mole is a SI unit of measurement that is used to calculate the quantity of any substance.
Aluminum Carbonate on Dissociates into Aluminum Ions and carbonate Ions
[tex]Al_2(CO_3)_3 = 2 Al6+^3 + 3 CO_3^-^2[/tex]
On dissociation [tex]Al_2(CO_3)_3[/tex] produces five Ions in total.
Al⁺² = 2
CO₃⁻² = 3
Thus, The moles of ions produced are 5.
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When the pressure that a gas exerts on a sealed container changes from 22.5 psi to psi the temperature changes from 110 c to 65.0 c
Answer:
19.9 psi
Explanation:
Bromine dichloride, BrCl2, decomposes to form bromine and chlorine at equilibrium according to the following equation:
2BrCl2(g) + heat ⇌ Br2(g) + 2Cl2(g)
For the following change, how would the reaction shift (toward the products, reactants, or no change)?
The temperature is increased?
When the equilibrium of the decomposition of bromine dichloride is disturbed by increasing temperature, the reaction shifts towards the reactants according to Le Chatelier's principle.
If the temperature is increased for the decomposition of bromine dichloride, BrCl2, the reaction will shift towards the reactants. According to Le Chatelier's principle, if a chemical system at equilibrium experiences a change in concentration, temperature, volume, or pressure, then the equilibrium shifts to counteract the imposed change and re-establish equilibrium. In this endothermic reaction, heat is absorbed to convert BrCl2 into bromine, Br2, and chlorine, Cl2. Therefore, increasing the temperature adds heat to the system, which will shift the equilibrium towards the reactants (BrCl2) to absorb the excess heat.
3L of nitrogen gas is heated from 20°C to 80°C. What is the new volume of the gas, if pressure remains constant?
Consider the reaction below. CO(g) + Cl2(g) « COCl2(g) What is the most likely effect to the forward reaction if there is an increase in pressure on this reaction? The reactant surface area increases. The reaction rate decreases. The reaction is not affected at all. The reaction stops completely.
Answer:
The reaction rate decreases.
Explanation:
a 4 kilogram cat is resting on top of a bookshelf that is 3 meters high what is the cats gravitational potential energy relative to the floor if the acceleration due to gravity is 9.8m/s A.7j B. 29j C.12j D.118j
What about uranium room temperature is it "SOLID LIQUID or GAS)?
The solubilty of a gas is 1.6 g/l at 760 mmhg what is the solubility of the same gas at a pressure of 2.5 atm? assume temperature to be constant
Define what electronegativity is and explain the pattern on the table as you move to the right across it.
The smallest piece of a compound that retains characteristics of a compound is
Which acid dissociation constant (ka indicates the weakest acid? 8.5 × 10–3m 1.5 × 10–10m 3.5 × 10–7m 5.1 × 10–5m?
Recall that your hypothesis is that these values are the fraction of atoms that are still radioactive after n half-life cycles. Record in the appropriate blanks.
Answer : A= 0.5, B = 0.25 , C = 0.125, D = 0.015625 and E = 0.00390625
Explanation :
Half life of a substance is defined as the amount of time taken by the substance to reduce to half of its original amount.
Here n represents the number of half lives.
The amount of substance that remains after n half lives can be calculated using the given formula, [tex] 0.5^{n} [/tex]
So when we have n =1,
Fraction of substance that remains = 0.5¹ = 0.5.
That means after first half life over, the amount of substance that remains is 0.5 times that of original.
Therefore we have A = 0.5
When n = 2, we have 0.5² = 0.25
So when 2 half lives are over, the amount of substance that remains is 0.25 times that of original
Therefore B = 0.25
When n = 3, we have 0.5³ = 0.125
So when 3 half lives are over, the amount of substance that remains is 0.125 times that of original.
Therefore we have C = 0.125
When n = 6 , we have 0.5⁶ = 0.015625
So D = 0.015625
When n = 8, we have 0.5⁸ = 0.00390625
Therefore E = 0.00390625
The values for A, B, C, D and E are 0.5, 0.25, 0.125, 0.015625 and 0.00390625 respectively.
15 POINTS
When calcium forms an ion, what is its charge?
2+
3+
2-
3-
The answer is:
A) 2+
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Identify the brønsted base in the forward reaction hpo2− 4 (aq) + hno3(aq) ⇀↽ no− 3 (aq) + h2po− 4 (aq). 1. h2po− 4 (aq) 2. hno3 3. hpo2− 4 4. no− 3
The Brønsted base in the forward reaction HPO4²-(aq) + HNO3(aq) ⇀↽ NO3¯ (aq) + H2PO4¯ (aq) is HPO4²-(aq) because it accepts a proton in this reaction.
Explanation:To identify the Brønsted base in the reaction HPO4²-(aq) + HNO3(aq) ⇀↽ NO3¯(aq) + H2PO4¯(aq), let's recognize the definitions of a Brønsted-Lowry base and acid.
A Brønsted base is a proton (H+) acceptor, whereas a Brønsted acid is a proton donor. In the forward reaction, HNO3 donates a proton; making it the Brønsted acid. The species that accepts the proton is HPO4²-. Therefore, HPO4²- is the Brønsted base in the forward reaction of this equilibrium.
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In the reaction, HPO₄²⁻ is the Brønsted base as it accepts a proton from HNO₃. HNO₃ acts as the Brønsted acid. Therefore, option 3: HPO₄²⁻ is correct.
In the forward reaction HPO₄²⁻ (aq) + HNO₃ (aq) ⇄ NO₃⁻ (aq) + H₂PO₄⁻ (aq), we need to identify the Brønsted base.
A Brønsted base is defined as a substance that can accept a proton (H⁺). In this reaction:
HPO₄²⁻ is acting as a Brønsted base because it accepts a proton from HNO₃ to form H₂PO₄⁻. HNO₃ acts as a Brønsted acid since it donates a proton.So, the correct answer is option 3: HPO₄²⁻.
Complete Question.
Identify the Brønsted base in the forward reaction HPO₄²⁻ (aq) + HNO₃(aq) ⇄ NO₃⁻ (aq) + H₂P0₄⁻ (aq).
1. NO₃⁻
2. H₂PO₄⁻ (aq)
3. HPO₄²⁻
4. HNO₃
Which of the following tools could have become cross-contaminated during the experiment if you had not cleaned them carefully between successive tests?
A. Spoon
B. Beaker
C. Stirring Rod
D. Graduated Cylinder
E. Distilled water in a spray bottle
Explanation:
When we are using spoon, beaker, stirring rod and graduated cylinder then they directly come in contact with the chemical we are using. Hence, if they are not washed thoroughly then chemicals remain deposited over them.
As a result, when successive test are performed using the same contaminated apparatuses then we do not get the desired results.
Whereas distilled water in a spray bottle if poured without touching or coming in contact with any kind of chemicals.
Hence, we can conclude that spoon, beaker, stirring rod and graduated cylinder are the tools that could have become cross-contaminated during the experiment if you had not cleaned them carefully between successive tests.
Answer:
A. Spoon, B. Beaker, C. Stirring Rod, D. Graduated Cylinder
Explanation: