In the nuclear transmutation represented by 168o(p, \alpha) 137n, the emitted particle is ________.

Answers

Answer 1
Answer is: the emitted particle is an alpha particle.

Nuclear reaction: ¹⁶O + p⁺ → ¹³N + α (alpha particle).
Alpha decay is radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and transforms into an atom with an atomic number that is reduced by two and mass number that is reduced by four.
When oxygen-16 gain one proton, atomic mass is 17, but when lose alpha particle atomic mass reduces by four to 13.


Related Questions

The mineral enargite is 48.41% cu, 19.02% as, and 32.57% s by mass. what is the empirical formula of enargite?

Answers

Answer is: the empirical formula of enargite is Cu₃AsS₄.
If we use 100 grams of enargite:
n(Cu) = 48,41 g ÷ 63.55 g/mol.
n(Cu) = 0.761 mol.
n(As) = 19.02 g ÷ 74.92 g/mol.
n(As) = 0.254 mol.
n(S) = 32.57 g ÷ 32.065 g/mol.
n(S) = 1.016 mol.
n(Cu) : n(As) : n(S) = 0.761 mol : 0.254 mol : 1.016 mol / 0.254.
n(Cu) : n(As) : n(S) = 3 mol : 1 mol : 4 mol.

Which of the following compounds is not ionic?

A. CaCI2
B. NaI
C. CO2
D. Na2O

(P.S. All the 2's are subscript!)

Answers

The correct option is C.
An ionic compound is one which is made up of ions, which are held together by electrostatic force called ionic bonding. The compounds are usually made up of electrically charged particles, they have high melting and boiling points and they are good conduct of electricity. Ionic compounds are typically made up of metals and non metals.
Thus, CO2 is not an ionic compound, it is a covalent compound.

Recrystallizing an anhydride (such as the product of this reaction) from water or an alcohol is rarely a good idea. explain why. be specific.

Answers

Final answer:

Recrystallization of an anhydride in water or alcohol is not effective because anhydrides will react with these solvents to form carboxylic acids or esters, respectively, thereby altering the compound instead of purifying it.

Explanation:

Recrystallizing an anhydride from water or an alcohol is often not ideal due to the reactive nature of anhydrides. Anhydrides undergo hydrolysis in the presence of water to form carboxylic acids, a process which is energetically favorable and further driven by the stabilization through hydrogen-bonding interactions among water molecules and the carboxylic acids. Moreover, anhydrides react with alcohols to yield esters. This means that instead of recrystallizing the anhydride, you are likely to convert it to other products, which defeats the purpose of recrystallization since you want to purify the anhydride, not change its chemical structure.

Lakes that have been acidified by acid rain can be neutralized by limiting the addition of limestone how much limestone is required to completely neutralize a 4.3 billion liter lake with a ph of 5.5

Answers

From the given pH, we calculate the concentration of H+:
     [H+] = 10^-pH = 10^-5.5
We then use the volume to solve for the number of moles of H+:
     moles H+ = 10^-5.5M * 4.3x10^9 L =  13598 moles
From the balanced equation of the neutralization of hydrogen ion by limestone written as
     CaCO3(s) + 2H+(aq)  → Ca2+(aq) + H2CO3(aq)
we use the mole ratio of limestone CaCO3 and H+ from their coefficients, which is 1 mole of CaCO3 is to react with 2 moles of H+, to compute for the mass of the limestone:
     mass CaCO3 = 13598mol H+(1mol CaCO3/2mol H+)
                               (100.0869g CaCO3/1mol CaCO3)(1kg/1000g) 
                            = 680 kg

The amount of limestone required to neutralize the lake is approximately [tex]\( 2.653 \times 10^4 \, \text{kg} \).[/tex]

To determine how much limestone ([tex]CaCO_3[/tex]) is required to neutralize a lake acidified by sulfuric acid ([tex]H_2SO_4[/tex]), we need to follow these steps:

1. Calculate the total mass of [tex]H_2SO_4[/tex] in the lake.

2. Determine the moles of [tex]H_2SO_4[/tex] present.

3. Use stoichiometry to find the moles of [tex]CaCO}_3[/tex] required to neutralize the [tex]H_2SO_4[/tex]

4. Convert the moles of [tex]CaCO}_3[/tex] to mass in kilograms.

Step 1: Calculate the Total Mass of [tex]H_2SO_4[/tex] in the Lake

The lake volume is [tex]\( 5.2 \times 10^9 \) liters.[/tex]

The concentration of [tex]H_2SO_4[/tex] is [tex]\( 5.0 \times 10^{-3} \) g/L.[/tex]

Total mass of [tex]H_2SO_4[/tex]

[tex]\[ \text{Total mass of H}_2\text{SO}_4 = \text{Concentration} \times \text{Volume} \][/tex]

[tex]\[ \text{Total mass of H}_2\text{SO}_4 = 5.0 \times 10^{-3} \, \text{g/L} \times 5.2 \times 10^9 \, \text{L} \][/tex]

[tex]\[ \text{Total mass of H}_2\text{SO}_4 = 2.6 \times 10^7 \, \text{g} \][/tex]

Step 2: Determine the Moles of [tex]H_2SO_4[/tex]

Molar mass of [tex]H_2SO_4[/tex]

[tex]\[ \text{H}_2\text{SO}_4 = 2 \times 1 + 32 + 4 \times 16 = 98 \, \text{g/mol} \][/tex]

Moles of [tex]H_2SO_4[/tex]

[tex]\[ \text{Moles of H}_2\text{SO}_4 = \frac{\text{Total mass of H}_2\text{SO}_4}{\text{Molar mass of H}_2\text{SO}_4} \][/tex]

[tex]\[ \text{Moles of H}_2\text{SO}_4 = \frac{2.6 \times 10^7 \, \text{g}}{98 \, \text{g/mol}} \][/tex]

[tex]\[ \text{Moles of H}_2\text{SO}_4 = 2.653 \times 10^5 \, \text{mol} \][/tex]

Step 3: Use Stoichiometry to Find the Moles of [tex]CaCO}_3[/tex] Required

The neutralization reaction between [tex]H_2SO_4[/tex] and [tex]CaCO}_3[/tex] is:

[tex]\[ \text{H}_2\text{SO}_4 + \text{CaCO}_3 \rightarrow \text{CaSO}_4 + \text{CO}_2 + \text{H}_2\text{O} \][/tex]

From the balanced equation, 1 mole of [tex]H_2SO_4[/tex] reacts with 1 mole of [tex]CaCO}_3[/tex]

Therefore, moles of [tex]CaCO}_3[/tex] required:

[tex]\[ \text{Moles of CaCO}_3 = \text{Moles of H}_2\text{SO}_4 \][/tex]

[tex]\[ \text{Moles of CaCO}_3 = 2.653 \times 10^5 \, \text{mol} \][/tex]

Step 4: Convert the Moles of [tex]CaCO}_3[/tex] to Mass in Kilograms

Molar mass of [tex]CaCO}_3[/tex]

[tex]\[ \text{CaCO}_3 = 40 + 12 + 3 \times 16 = 100 \, \text{g/mol} \][/tex]

Mass of [tex]CaCO}_3[/tex]

[tex]\[ \text{Mass of CaCO}_3 = \text{Moles of CaCO}_3 \times \text{Molar mass of CaCO}_3 \][/tex]

[tex]\[ \text{Mass of CaCO}_3 = 2.653 \times 10^5 \, \text{mol} \times 100 \, \text{g/mol} \][/tex]

[tex]\[ \text{Mass of CaCO}_3 = 2.653 \times 10^7 \, \text{g} \][/tex]

Convert grams to kilograms:

[tex]\[ \text{Mass of CaCO}_3 = 2.653 \times 10^7 \, \text{g} \times \frac{1 \, \text{kg}}{1000 \, \text{g}} \][/tex]

[tex]\[ \text{Mass of CaCO}_3 = 2.653 \times 10^4 \, \text{kg} \][/tex]

The complete Question is

Lakes that have been acidified by acid rain can be neutralized by the addition of limestone (CaCO3). How much limestone in kg would be required to completely neutralize a 5.2 x 10^9 L lake containing 5.0 x 10-3 g of H2SO4 per liter?

Which particle changes the mass of the isotope the most? which particle changes the mass of the isotope the most? electron capture positron emission gamma capture alpha particle neutron particle?

Answers

this question is absurd

Answer: Option (d) is the correct answer.

Explanation:

Species which contain same number of protons but different number of neutrons are known as isotope.  

For example, [tex]^{1}_{1}H[/tex] and [tex]^{3}_{1}H[/tex] are isotopes.

More is the mass of particle colliding with the isotope more will be the change in mass of an isotope due to emission of a heavier particle.

As alpha ([tex]^{4}_{2}He[/tex]) particle is heavier then a neutron, positron and gamma particles.

For example, [tex]^{14}_{7}N + ^{4}_{2}He \rightarrow ^{17}_{8}O[/tex]

Therefore, we can conclude that alpha particle changes the mass of the isotope the most.

A 36.41-g sample of calcium carbonate (CaC O 3 )
contains 14.58 g of calcium and 4.36 g of carbon.

What is the mass of oxygen contained in the sam-
ple? What is the percent by mass of each element in

this compound?

Answers

m(O) = m(CaCO₃) - m(Ca) - m(C).
m(O) = 36.41 g - 14.58 g - 4.36 g.
m(O) = 17.47 g.
ω(Ca) = m(Ca) ÷ m(CaCO₃) · 100%.
ω(Ca) = 14.58 g ÷ 36.41 g · 100%.
ω(Ca) = 40 %; mass percent of calcium.
ω(C) = m(C) ÷ m(CaCO₃) · 100%.
ω(C) = 4.36 g ÷ 36.41 g · 100%
ω(C) = 12%; mass percent of carbon.
ω(O) = 100% - ω(Ca) - ω(C).
ω(O) = 100% - 40% - 12%.
ω(O) = 48%; mass percent of oxygen.

Sodium is produced by electrolysis of molten sodium chloride. what are the products at the anode and cathode, respectively?

Answers

When sodium chloride is molten:
NaCl ------> Na⁺ +Cl⁻
Anod (+)                                           |             Cathode (-)
2Cl⁻-2e⁻ ---> Cl2(gas)                     |          Na⁺ + e⁻ -----> Na⁰(s)

Write the balanced nuclear equation for β− decay of sodium−26. include both the mass numbers and the atomic numbers with each nuclear symbol. use the sup-subscript button in the answer palette to enter these numbers correctly. greek letters can be accessed in the drop-down menu that says -select−.

Answers

β- decay is the emission of an electron by converting a neutron into a proton.

After doing β- decay, the formed daughter nucleus has the same number of mass number as the parent atom but the atomic number has increased by 1 and neutron number has reduced by 1.

If Na²⁶₁₁ (number of neutrons = 26 - 11 = 15) undergoes a β- decay, then produced daughter atom must have 12 protons and 14 neutrons. Hence, the daughter atom should be Mg.

Na²⁶₁₁ → Mg²⁶₁₂ + ₋₁⁰β + energy

The balanced nuclear equation for beta decay of sodium-26 is represented as Na²⁶₁₁ → Mg²⁶₁₂ + β₋₁⁰ + energy.

What is beta decay?

Beta decay is one of the type of radioactive nuclear decay reaction in which emission of a beta particle takes place from the atomic nuclear.

Beta particle define by the symbol β₋₁⁰ i.e. this particles has no mass but having a negative charge on it. In this reaction atomic mass of the parent atom is equal to the new formed daughter atom. But in this reaction number of neutron is reduced by 1 and number of proton is increased by one of parent atom. So, balanced nuclear equation for β− decay of sodium−26 is represnted as:

Na²⁶₁₁ → Mg²⁶₁₂ + β₋₁⁰ + energy

Hence balanced nuclear equation for the beta decay is represented above.

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A solution of 0.90 g of an unknown nonelectrolyte in 100 ml of water at 27◦c has an osmotic pressure of 0.55 atm. what is the molecular weight of this compound? (assume

Answers

Osmotic pressure is mathematically expressed as
π = CRT
where,  C = concentration of solution
R = gas constant = 0.082 atm mol-1 K-1
T = temperature = 300 K
π = osmotic pressure = 0.55 atm

∴ 0.55 = C X 8.314 X 300
∴C = 0.022 M

Now, conc of solution (in terms of molarity) = [tex] \frac{\text{weight of solute}}{\text{molecular weight X volume of solution(l)}} [/tex]

Given: weight of solute = 0.9 g
volume of solution = 100 ml = 0.1 l

∴ 0.022 = [tex] \frac{0.9}{\text{molecular weight X 0.1}} [/tex]
∴ Molecular weight = 4.09 g/mol

Which carbonyl compounds do not undergo an aldol reaction when treated with −oh in h2o? select all that apply?

Answers

Answers:
              Among many few compounds are shown below which can not undergo Aldol Condensation reactions.

Explanation:
                   Aldol Condensation reactions are given by those carbonyl compounds which are capable of forming conjugate bases called as Enolates. Enolates are formed when carbonyl compounds having hydrogen atoms at alpha position are treated with strong bases. This hydrogen atom at alpha position is mildly acidic in nature and readily donated to base as the upcoming conjugate base i.e. has stability due to resonance. 
                  So those carbonyl compounds which lacks these acidic protons at alpha position are not able to form enolates, Hence, unable to undergo Aldol Condensation reactions. Few examples are attached below,

Carbonyl compounds that do not undergo an aldol reaction include those without alpha-hydrogens like formaldehyde and benzaldehyde, as well as esters, acids, and amides.

These compounds either lack necessary alpha-hydrogens or have structures that are unfavorable for aldol reactions.

In an aldol reaction, carbonyl compounds like aldehydes and ketones with alpha-hydrogens can react in the presence of a base such as hydroxide (−OH) in water. However, not all carbonyl compounds undergo this reaction.

Carbonyl compounds that do not undergo an aldol reaction include those without alpha-hydrogens, such as formaldehyde and benzaldehyde. Additionally, carbonyl compounds like esters, acids, and amides typically do not participate in aldol reactions due to their structural properties.

Examples of Carbonyl Compounds Not Undergoing Aldol Reaction:

Formaldehyde (H-CHO)Benzaldehyde (C₆H₅CHO)Ester (R-COOR')Acid (R-COOH)Amide (R-CONH₂)

These compounds either lack the necessary alpha-hydrogens or have structures that are unfavorable for aldol reactions.

A 135 g sample of carbon disulfide requires 43.2 kj of heat to vaporize completely. what is the enthalpy of vaporization for carbon disulfide?
a. 1.77 kj/mol
b. 24.4 kj/mol
c. 76.2 kj/mol
d. 0.320 kj/mol
e. 3.13 kj/mol

Answers

Molecular weight of CS2 = 76.14 g

number of moles of CS2 = [tex] \frac{weight.of.CS2}{molecular.weight} [/tex]
                                        = [tex] \frac{135}{76.14} [/tex]
                                        = 1.773

Now, 1.733 mol requires 43.2 kj of heat to vaporize.
∴  1 mol will require [tex] \frac{43.2}{1.77} [/tex] = 24.4 kj/mol

Thus, correct answer is option B

Complete the reactions to show how butanoic acid may be converted to butanal.

Answers

Butanoic Acid is converted to Butanal in two steps;

Step 1: Conversion of Butanoic Acid into Butyryl Chloride:

Butanoic Acid when treated with Thionyl Chloride gives Butyryl Chloride, SO₂ and HCl gases. This step is selected due to conversion of a bad leaving group (-OH) into a good leaving group (-Cl).

Step 2: Conversion of Butyryl Chloride to Butanal:

In this reaction the Butyryl Chloride is reduced to Butanal by treating Butyryl Chloride with a mild reducing agent i.e. Lithium tri tert-butoxy aluminum hydride.

Final answer:

Butanoic acid can be converted to butanal via a reduction process using a reducing agent such as lithium aluminum hydride, followed by hydrolysis.

Explanation:

Converting butanoic acid to butanal involves a reduction process, which can be carried out using reducing agents such as lithium aluminum hydride (LiAlH₄) or borane (BH₃). The reaction with LiAlH₄ is usually carried out in dry ether as a solvent, and it can be followed by careful hydrolysis to give the aldehyde, butanal. The overall reaction can be summarized as:

Butanoic acid (C₄H₈O₂) is treated with the reducing agent LiAlH₄.

The acid is reduced to the corresponding aldehyde, butanal (C₄H₈O).

After the reduction, the reaction mixture is hydrolyzed, which involves adding water to the reaction mixture.

This is different from esterification, which is the reaction between an acid and an alcohol, as described in the esterification of ethanol and butanoic acid to form ethyl butanoate and water.

The biochemical production of butanol from butyric acid is similarly not a direct route for synthesizing butanal, but it is an important process for biomass conversion.

If 32.5 grams of CaO are dissolved in 212 grams of water, what is the concentration of the solution in percent by mass?

6.52% CaO

8.67% CaO

13.3% CaO

15.3% CaO

Answers

percent by mass of CaO= Mass of solute/ moles of solution x 100%

(32.5g)/ (32.5g+212g) x 100%
= 13.29 and when you round it becomes 13.3% CaO

Answer:

Concentration of solution in percent by mass is 13.3% CaO

Explanation:

% by mass = [tex]\frac{mass of solute}{mass of solution}\times 100[/tex]

Here solute is CaO and solvent is water.

So, mass of solution = (mass of solute)+(mass of solvent)

                                  = (mass of CaO)+(mass of water)

                                   = 32.5 g + 212 g

                                    = 244.5 g

So, Concentration of solution by percent mass = [tex]\frac{mass of CaO}{mass of solution}\times 100[/tex] = [tex]\frac{32.5}{244.5}\times 100[/tex] = 13.3 %

Which of the temperatures below is most likely to be the boiling point of water at 880 torr?view available hint(s)which of the temperatures below is most likely to be the boiling point of water at 880 torr?92°c105°c100°c?

Answers

Boiling point  is the temperature at which the vapor pressure of the liquid equals the surrounding pressure.

Above boiling point point, liquid get converted into vapour.

Now, boiling point of water is 100 oC at room pressure. Room pressure is equal to 760 torr. Thus, at 100 oC, vapour pressure of water becomes equal to 760 torr.

Now, if external pressure is increased to 880 torr, more heat is to be supplied so that vapour pressure of water equals 880 torr.

So, at 880 torr, boiling point of water will be more than 100 oC. In present case, most like the boiling point of water is equal to 105 oC.


Final answer:

Using the Clausius-Clapeyron equation, we can derive that the boiling point of water at 880 torr is closest to 90°C. Thus, among the given options, the boiling point of water at 880 torr is most likely to be 92°C.

Explanation:

The subject question is considering the boiling point of water at differing pressures. The standard boiling point of water is 100°C at 1 atmospheric pressure (or 760 torr). However, boiling point changes with changes in atmospheric pressure.

 By using the Clausius-Clapeyron equation, which establishes a relationship between the vapor pressure and temperature of a substance, we can establish that at 880 torr, the boiling point is likely to be close to 90°C, given that the vapor pressure of water is 68kPa at about this temperature. Therefore, among the options given, 92°C is the most likely boiling point of water at 880 torr.

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Calculate the k sp for zinc hydroxide if the solubility of zn (oh)2 in pure water is 2.1 × 10-4 g/l. calculate the k sp for zinc hydroxide if the solubility of zn (oh)2 in pure water is 2.1 × 10-4 g/l. 2.9 × 10-3 1.5 × 10-3 9.9 × 10-18 3.8 × 10-17

Answers

Zinc hydroxide is a uni-bi type of electrolyte.
For such systems, k sp = 4S^3
where S = solubility in mol/l

Now for Zinc hydroxide, molecular weight = 99.4

so,  solubility = 2.1 x 10-4 g/l = 2.11 X 10^-6 mol/l
Finally, k sp = 4S^3 = 4 X (2.11 X 10^-6)^3 = 3.77 X 10^-17

The [tex]\( K_{sp} \)[/tex] for zinc hydroxide is [tex]\[ 3.8 \times 10^{-17}}\][/tex]

1. Molar mass of  [tex]\( \text{Zn(OH)}_2 \)[/tex]:

  [tex]\[ \text{Zn} = 65.38 \, \text{g/mol}, \, \text{O} = 16.00 \, \text{g/mol}, \, \text{H} = 1.01 \, \text{g/mol} \][/tex]

 [tex]\[ \text{Molar mass} = 65.38 + 2 \times (16.00 + 1.01) = 99.40 \, \text{g/mol} \][/tex]

2. Molar solubility [tex]\( s \)[/tex]:

  [tex]\[ \text{Solubility} = 2.1 \times 10^{-4} \, \text{g/L} \][/tex]

 [tex]\[ s = \frac{2.1 \times 10^{-4}}{99.40} \approx 2.11 \times 10^{-6} \, \text{mol/L} \][/tex]

3. Ksp expression:

 [tex]\[ \text{Zn(OH)}_2 \rightleftharpoons \text{Zn}^{2+} + 2\text{OH}^- \][/tex]

 [tex]\[ K_{sp} = [\text{Zn}^{2+}][\text{OH}^-]^2 = s \cdot (2s)^2 = 4s^3 \][/tex]

4. Calculate [tex]\( K_{sp} \):[/tex]

 [tex]\[ K_{sp} = 4 \times (2.11 \times 10^{-6})^3 = 4 \times 9.39 \times 10^{-18} \approx 3.76 \times 10^{-17} \][/tex]

Nitrogen-13 has a half-life of 10 minutes. how much of a 128 mg sample would remain after 20 minutes?

Answers

The half-life of a radioisotope describes the amount of time it takes for said isotope to decay to one-half the original amount present in the sample.

Nitrogen-13, because it has a half-life of ten minutes, will experience two half-lives over the course of the twenty minute period. This means that 25% of the isotope will remain after this.

0.25 x 128mg = 32mg

32mg of Nitrogen-13 will remain after 20 minutes.
Final answer:

After 20 minutes, approximately 32 mg of the 128 mg sample of Nitrogen-13 would remain.

Explanation:

The half-life of a radioactive isotope is the time required for half of the atoms in a sample to decay.

In this case, we are given that the half-life of Nitrogen-13 is 10 minutes. This means that after every 10 minutes, half of the sample will decay.

Since 20 minutes have passed, we need to determine how many half-lives have occurred. There have been 2 half-lives because 20 divided by 10 equals 2.

Therefore, after 2 half-lives, one-fourth of the sample will remain (since half of the original sample will decay after each half-life).

To find out how much of a 128 mg sample would remain after 20 minutes, we multiply the original amount by one-fourth:

128 mg x 1/4 = 32 mg

After 20 minutes, approximately 32 mg of the 128 mg sample of Nitrogen-13 would remain.

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The normal boiling point of water is 100.0 °c and its molar enthalpy of vaporization is 40.67 kj/mol. what is the change in entropy in the system in j/k when 51.1 grams of steam at 1 atm condenses to a liquid at the normal boiling point?

Answers

we are going to use this formula:

Δ H = T * ΔS

when Δ H is the change in enthalpy 

and T is the temperature in Kelvin = 100+273= 373 K

and ΔS is the change in entropy

but first, we need to get the value of ΔH:

ΔH = mass * molar mass per mole * enthalpy of vaporization

by substitution:

ΔH = 51.1 g * (1 mole/18g) * 40.67KJ/mole

      = -115.5 KJ

we use negative sign because this is an exothermic reaction.

by substitution on the first formula, we will get the change of entropyΔS:

ΔS = ΔH / T

     = -115.5 KJ / 373K

     = 310 J/K
Final answer:

The change in entropy in the system is 308.3 J/K.

Explanation:

The change in entropy in the system can be calculated using the formula ∆S = ∆Hvap/T. Here, ∆Hvap is the molar enthalpy of vaporization of water, which is given as 40.67 kJ/mol. T is the temperature in Kelvin, which can be calculated by adding 273.15 to the boiling point of water in Celsius. So, T = 100.0 + 273.15 = 373.15 K. Plugging in these values in the formula, we get:

∆S = (40.67 kJ/mol)/(373.15 K) = 0.1089 kJ/(mol·K)

Now, we need to convert grams of steam to moles of steam. The molar mass of water is 18.015 g/mol. So, 51.1 g of steam is equal to (51.1 g)/(18.015 g/mol) = 2.835 mol. Multipling this with the change in entropy, we get:

∆S = (0.1089 kJ/(mol·K)) · (2.835 mol) = 0.3083 kJ/K

Finally, to convert kJ/K to J/K, we multiply by 1000:

∆S = (0.3083 kJ/K) · (1000 J/1 kJ) = 308.3 J/K

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hi i'm having trouble solving this question

" if 7.54 grams of Al reacts with excess of H2SO4, and makes 0.33g of H2 . What is the % yield of H2gas produced? 


Answers

Answer is:  the % yield of hydrogen gas produced is 58.9%.
m(Al) = 7.54 g.
n(Al) = m(Al) ÷ M(Al).
n(Al) = 7.54 g ÷ 27 g7mol.
n(Al) = 0.28 mol; amount of substance.
From chemical reaction: n(Al) : n(H₂) = 1 : 1.
n(H₂) = 0.28 mol.
m(H₂) = 0.28 mol · 2 g/mol.
m(H₂) = 0.56 g.
%yield = 0.33 g ÷ 0.56 g · 100%.
%yield = 58.9%.

The jaeger reading cards are used to test _____ vision

Answers

The Jaeger reading cards are used to test near vision. It's usually held by a patient at a certain distance from the eye depending on the size being read. The smallest letters one can read is what determines their visual acuity!

The Jaeger reading cards are used to test near vision. The correct answer is "near" vision.

The Jaeger reading cards are used to test near vision, which is the ability to see objects clearly at a close distance, typically around 14 to 16 inches away from the eyes. This type of vision is important for activities such as reading, writing, and working on a computer. The Jaeger chart consists of blocks of text in various sizes, with the smallest print at the bottom and the largest at the top. A person being tested reads the text from top to bottom until they can no longer clearly distinguish the letters, which helps determine their near visual acuity.

A sample of seawater contains 1.3g of calcium ions in 3,100kg of solution. what is the calcium ion concentration of this solution in units of ppm?

Answers

unit ppm stands for parts per million. in terms of mass, ppm is equivalent to mg/kg.
since 1 kg is 10⁻⁶ mg, 1 kg is equivalent to million mg.
therefore mg/kg is also ppm.
there are 1.3 g of Ca ions in 3100 kg
if 3100 kg contains - 1.3 g of Ca
then 1 kg contains - 1.3 g / 3100 kg
then Ca ions - 0.42 x 10⁻³ g/kg
Ca ion concentration - 0.42 mg/kg 
therefore Ca ion concentration is 0.42 ppm

To lift a load of 100 N a distance of 1 m an effort of 25 N must be applied over an inclined plane of length 4 m. What must be done to lift the load 2 m, using the same effort? A.Use an inclined plane of length 8 m.

B.Use an inclined plane of length 2 m.

C.Use an inclined plane of length 10 m

D.Use an inclined plane of length 16 m.

Answers

The answer is A, use an inclined plane of length 8.

Answer: The correct answer is A) Use an inclined plane of 8 m

Work :

Work is defined as force applied to an object to move it to some distance . It is calculated as product of force and displacement .

W = F* d

Where : W =work (N-m) F = force (N) d = displacement (m)

When a body is lifted , work can be expressed as :

W = m*g*h ( h = height )

Also force due to gravitation can be given as

F = m* g

where :

g = gravitational acceleration ([tex] 9.8 \frac{m}{s^2} [/tex]

Hence Work can be written as : W = F * h

Given :

Force on load due to gravitation = 100 N Height = 2 m

Force applied = 25 N displacement = ?

Work done to lift the load to 2 m = F * h

= 100 N * 2 m = 200 N-m

Plugging W = 200 N-m in work formula

W = F* d

200 N-m = 25 N * d

Dividing both side by 25 N

[tex] \frac{200N-m}{25 N} = \frac{25 N * d}{25 N} [/tex]

d = 8 m

Hence, to lift the load using 25 N , the inclined plane of 8 m can be used .

A 642 mL sample of oxygen gas at 23.5°C and 795 mm Hg, is heated to 31.7°C and the volume of the gas expands to 957 mL. What is the new pressure in atm?

Answers

Let's assume that O₂ is an ideal gas.

We can use combined gas law,
 PV/T = k (constant)

Where, P is the pressure of the gas, V is volume of the gas and T is the temperature of the gas in Kelvin.

For two situations, we can use that as,
P₁V₁/T₁= P₂V₂/T₂

P₁ = 795 mm Hg
V₁ =  642 mL
T₁ = (273 + 23.5) K = 296.5 K
P₂ = ?
V₂ = 957 mL
T₂ = (273 + 31.7) K = 304.7 K

By applying the formula,

795 mm Hg x 642 mL / 296.5 K = P₂ x 957 mL / 304.7 K
                                              P₂ = 548.07 mm Hg
                                              P₂ = 548 mm Hg
760 mmHg = 1 atm
548 mm Hg = 1 atm x (548 mmHg / 760 mmHg) = 0.721 atm

Pressure of gas = 
548 mm Hg = 0.721 atm

¿A shaker of salt substitute contains 1.6 oz of K. What is the activity, in milliCuries, of the potassium in the shaker? The activity is 7 microcuries (µCi)

Answers

We know K-40 (potassium having atomic mass 40 g) is radioactive and its natural abundance is 0.012% 
So for 1 mol of potassium contains 0.00012 mol of K-40 
Now 1.6 oz of K = 45.36 g of K
average atomic weight of K = 39.1 g
so 45.36 g of K contains:
(45.36 / 39.1) * 0.00012 * 6.022 x 10²³ (atoms of K-40)
= 8.4 x 10¹⁹ atoms of K-40
We know, activity A is:
A = 0.693 / t1/2 N₀
[t1/2 : half life time and N₀ : initial number of atoms]
t1/2 of K-40 = 1.28 x 10⁹ years
    = 4.04 x 10¹⁶ seconds
So A = (0.693 / 4.04 x 10¹⁶) * (8.4 x 10¹⁹ ) = 1441 cps
A = 141 x (1/3.7 x 10¹⁰)   because 3.7 x 10¹⁰ cps = 1 Ci
A = 3.9 x 10⁻⁸ Ci  = 3.9 x 10⁻⁵ millicurie

The normal boiling point of ethanol (c2h5oh) is 78.3 °c and its molar enthalpy of vaporization is 38.56 kj/mol. what is the change in entropy in the system in j/k when 42.2 grams of ethanol at 1 atm condenses to a liquid at the normal boiling point?

Answers

when the entropy change of vaporization
       
 = enthalpy of vaporization/boiling point temperature 

when we have the enthalpy of vaporization = 38560 J/mol

and the boiling point temperature in Kelvin = 78.3 + 273 = 351.3 K

by substitution:

∴the entropy change of vaporization = 38560J/mol/351.3K

                                                               = 109.76 J/K/mol

and when the liquid has lesser entropy than the gas and we here convert from

gas to liquid so, the change in entropy = -109.76 J/K/mol

now, we need the moles of C2H5OH = mass/molar mass when the molar

mass of C2H5OH = 46 g/mol and mass = 42.2 g 

∴ moles of C2H5OH = 42.2 g / 46 g/mol = 0.92 moles

when 1 mol of C2H5OH turns in liquid entropy change →-109.76 J/K/mol

∴ 0.92 mol of C2H5OH → X

∴ X entropy change when 0.92 mol = -109.76 *0.92 mol / 1 mol

                                                             = 84.64 J/K


The change in the randomness of the system is the entropy change. The entropy change after condensation at the standard boiling point is 84.64 J/K.

What is the entropy change?

When a system undergoes the addition or deletion of the reactant and the products, then the disorder of the system is known as entropy change.

Given,

Enthalpy of vaporization = 38560 J/mol

Boiling point temperature = 351.3 K

[tex]\begin{aligned}\text{Entropy change of vaporization} &= \dfrac{\text{enthalpy of vaporization}}{\text{boiling point temperature}}\\\\&= \dfrac{38560}{351.3}\\\\&=109.76 \;\rm J/K/mol\end{aligned}[/tex]

Here, liquid has less entropy than gas hence the change in entropy is  -109.76 J/K/mol.

Moles of ethanol is calculated as:

[tex]\begin{aligned}\rm moles &= \dfrac{\rm mass}{\rm molar\; mass}\\\\&= \dfrac{42.2}{46}\\\\&= 0.92 \;\rm moles\end{aligned}[/tex]

If 1 mole of ethanol has an entropy change of -109.76 J/K/mol. Then, 0.92 moles will have,

[tex]\dfrac{-109.76 \times 0.92}{1} = 84.64\;\rm J/K[/tex]

Therefore, 84.64 J/K is the entropy change.

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How many compounds, of the ones listed below, have hydrogen bonding? ch3(ch2)2nh2 ch3(ch2)2nh(ch2)4ch3 (ch3ch2)2n(ch2)4ch3?

Answers

Answer:
            Following two compounds have Hydrogen Bond Interactions;

                     1)  CH₃(CH₂)₂NH₂  (Propan-1-amine)

                     2)  CH₃(CH₂)₂NH(CH₂)₄CH₃  (N-propylpentan-1-amine)

Explanation:
                   Hydrogen Bond Interactions are formed between those molecules which has hydrogen atoms covalently bonded to most electronegative atoms like Fluorine, Oxygen and Nitrogen. This direct attachment of Hydrogen to electronegative atom makes it partial positive resulting in hydrogen bonding with neighbor's partial negative most electronegative atom. So, in above selected compounds it can be seen that both compounds contain hydrogen atoms directly attached to Nitrogen atoms, Therefore, allowing them to form Hydrogen Bonding Interactions.

The correct answer is a. 2 compounds have hydrogen bonding among the listed below.

To determine how many of the given compounds have hydrogen bonding, we must identify if they have hydrogen atoms attached to highly electronegative atoms like nitrogen (N), oxygen (O), or fluorine (F).

The compounds listed are:

CH₃(CH₂)₂NH₂CH₃(CH₂)₃NH(CH₂)₂CH₃(CH₃CH₂)₂N(CH₂)₄CH₃

Analysis

CH₃(CH₂)₂NH₂: Contains an N-H bond, so it can form hydrogen bonds.CH₃(CH₂)₃NH(CH₂)₂CH₃: Contains an N-H bond, so it can form hydrogen bonds.(CH₃CH₂)₂N(CH₂)₄CH₃: Does not contain an N-H bond, so it cannot form hydrogen bonds.

Based on this analysis, 2 out of the 3 compounds can form hydrogen bonds. Therefore, the correct answer is a. 2.

Correct question is: How many compounds, of the ones listed below, have hydrogen bonding?
CH₃(CH₂)₂NH₂  , CH₃(CH₂)₃NH(CH₂)₂CH₃ , (CH₃CH₂)₂N(CH₂)₄CH₃ ?
a. 2
b. 1
c. 0
d. 3

the transfer of a section of DNA from one organism into the DNA of another organism by scientists is called

Answers

I am going toward selective breeding however it can also be genetic engineering. 

The transfer  of a section of DNA from one organism into the DNA of another organism by scientists is called genetic engineering.

What is DNA?

DNA  is a hereditary material  which is present in human beings as well as all other living organisms.  Every cell which is present in an organism's body has DNA  which is the same. Most of the DNA is situated in the cell's nucleus and small amount of it can be found in the cell's mitochondria as well.

Information which is stored in DNA is stored as codes made up of four chemical bases namely, adenine, thymine , cytosine and guanine.Human DNA consists of 3 billion bases .The order of the bases determines information which is required for building and maintaining an organism.

DNA bases are capable of pairing up with each other. Adenine pairs with thymine and guanine pairs up with cytosine .Each base is also attached to a sugar molecule  and a phosphate group. A base, phosphate  sugar are together called as nucleotides.

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An apple pudding is prepared by combining apples, sugar, butter, and lemon juice. To which category does it belong? compound mixture element molecule atom

Answers

Mixture as...

Each individual ingredient is an element.
Compound means they are chemically bound together which is not true in this case.

mixture   between them  

What is the standard emf of a galvanic cell made of a cd electrode in a 1.0 m cd(no3)2 solution and a cr electrode in a 1.0 m cr(no3)3 solution at 25°c?

Answers

Standard reduction potential of Cd2+ = -0.403 v
Standard reduction potential of Cr3+ = -0.74 v

Here, reduction potential of Cd2+ is higher as compared to Cr3+. Hence, it will preferentially undergo reduction. 

The electrochemical cell is represented as
Cr/Cr3+// Cd2+/Cd

Now, standard EMF of cell = E = ECd2+/Cd - ECr3+/Cr  
                                                  = - 0.403. - (-0.74)
                                                  = 0.337 v


Final answer:

The standard emf of a galvanic cell with a Cd and Cr electrode in solutions of their respective 1.0 M nitrates at 25°C is 0.34 V.

Explanation:

To determine the standard emf of a galvanic cell made of a Cd electrode in a 1.0 M Cd(NO₃)₂ solution and a Cr electrode in a 1.0 M Cr(NO₃)₃ solution at 25°C, we must first identify the half-reactions taking place at each electrode and their standard reduction potentials (E°).

The standard half-cell potentials (available in standard reduction potential tables) for Cd2+ and Cr3+ are as follows:

 

The cathode is where reduction takes place, so the Cr3+ half-reaction will be the reduction (gain of electrons), and the Cd2+ half-reaction will be the oxidation at the anode (loss of electrons).

Next, we calculate the standard cell potential (E°cell) using the formula:

E°cell = E°cathode - E°anode

Since the Cr3+ half-reaction has the more negative standard reduction potential, it will be reversed to represent oxidation when it functions as the anode reaction. This gives us:

E°cell = (-0.40 V) - (-0.74 V) = 0.34 V

The positive standard cell potential indicates that the galvanic cell reaction is spontaneous under standard state conditions.

What is the daughter nucleus (nuclide) produced when 90sr undergoes beta decay by emitting an electron? replace each question mark with the appropriate integer or symbol?

Answers

beta decay by emitting an electron is called as β⁻ decay. when this happens, a neutron of the element converts into a proton by emitting an electron. Hence, the mass of daughter nucleus is same as parent atom but atomic number/number of protons is higher by 1 than atomic number of parent atom.

Sr has atomic number as 38.

After β⁻ decay, the daughter nucleus will have atomic number as 38 + 1 = 39.
Hence, the daughter nucleus should be Y (Yttrium). Formula is,

₃₈⁹⁰Sr → ₃₉⁹⁰Y + ₋₁⁰β + energy

Final answer:

The daughter nuclide produced when ¹°Sr undergoes beta decay is ¹°Y (yttrium-90), which is represented by the nuclear equation ¹°Sr → ¹°Y + β⁻.

Explanation:

When ¹°Sr undergoes beta decay, it emits an electron (beta particle) and transforms into a different element. The loss of the electron results in an increase of the atomic number by one while the mass number remains the same. Therefore, the new atomic number will be 39 (as strontium has atomic number 38), and the mass number stays at 90. The daughter nuclide produced from this decay is ¹°Y (yttrium-90).

The nuclear equation for this ß-decay process is:
¹°Sr → ¹°Y + β⁻

Which statement best describes how the scientific community analyzes data?

Answers

Answer:

Scientists can come to different conclusions based on the same data

Explanation:

Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Thus,  scientists can come to different conclusions based on the same data is the statement that describes how the scientific community analyzes data.

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.

So as we saw that matter has some mass so mass can be measured in gram only. Mass can also be represented as number of molecules. We also saw that matter occupy some volume and that volume is measured only in liter. Scientists can come to different conclusions based on the same data is the statement that describes how the scientific community analyzes data.

Thus,  scientists can come to different conclusions based on the same data is the statement that describes how the scientific community analyzes data.

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