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determine the mass in grams of 3.75 x 10^21 atoms of zinc. (the mass of one mole of zinc is 65.39 g)
Answer: The mass in [tex]3.75 \times 10^{21}[/tex] atoms of zinc is 0.405 g.
Explanation:
Given: Atoms of zinc = [tex]3.75 \times 10^{21}[/tex]
It is known that 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] atoms. So, the number of moles in given number of atoms is as follows.
[tex]Moles = \frac{3.75 \times 10^{21}}{6.022 \times 10^{23}}\\= 0.622 \times 10^{-2}\\= 0.0062 mol[/tex]
As moles is the mass of a substance divided by its molar mass. So, mass of zinc (molar mass = 65.39 g/mol) is calculated as follows.
[tex]Moles = \frac{mass}{molar mass}\\0.0062 mol = \frac{mass}{65.39 g}\\mass = 0.405 g[/tex]
Thus, we can conclude that the mass in [tex]3.75 \times 10^{21}[/tex] atoms of zinc is 0.405 g.
1. Which of the combinations in the lab activity had indications that a chemical change occured? Defend your argument with evidence.
2. Which of the combinations in the lab activity had indications that a physical change occured? Defend your argument with evidence.
3. Are all physical changes reversible? Explain your answer using an example you've observed in your everyday life.
4. Give an example of something you've observed in your everyday life that is a chemical reaction. How did you know it was a chemical reaction?
Answer:The green growing on the penny of copper and the rust forming on the nail of iron are chemical changes. Boiling away salt water, scraping iron filings from a mixture of sand with a magnet, and breaking a rock with a hammer, are physical changes.
Explanation:
The tools shown in the diagram are used for gardening Each tool is made up
of two levers that are attached to each other. The handles are the input arms,
and the cutting blades are the output armo
Hand shears
Lopper
Which tool has a greater mechanical advantage, and why?
A. The lopper, because the input work is the same as the output work
B. The hand shears, because their shorter handles transfer force
more quickly to the cutting blade
C. The hand shears, because you can apply less total force to the
handles with one hand
D. The lopper, because its longer handles can produce more output
force with less input force
Answer:
D
Explanation:
The longer handles distribute the force across a longer distance.
I have 50.00 mL of 0.100 M ethyl amine (C2H5NH2). I gradually add a solution of 0.025 M nitric acid (HNO3) to the ethyl amine solution.
Required:
What is the pH after the addition of a total of 201 mL of the nitric acid?
Answer:
4.00 is the pH of the mixture
Explanation:
The ethyl amine reacts with HNO3 as follows:
C2H5NH2 + HNO3 → C2H5NH3⁺ + NO3⁻
To solve this question we need to find the moles of ethyl amine and the moles of HNO3:
Moles C2H5NH2:
0.0500L * (0.100mol/L) = 0.00500 moles ethyl amine
Moles HNO3:
0.201L * (0.025mol/L) = 0.005025 moles HNO3
That means HNO3 is in excess. The moles in excess are:
0.005025 moles HNO3 - 0.00500 moles ethyl amine =
2.5x10⁻⁵ moles HNO₃
In 50 + 201mL = 251mL = 0.251L:
2.5x10⁻⁵ moles HNO₃ / 0.251L = 9.96x10⁻⁵M = [H+]
As pH = -log [H+]
pH = -log 9.96x10⁻⁵M
pH = 4.00 is the pH of the mixture
The data shows the number of years that 30 employees worked for an insurance company before retirement. is the population mean for the number of years worked, and % of the employees worked for the company for at least 10 years. (Round off your answers to the nearest integer.)
Answer:
14
73%
Explanation:
The mean Number of years worked :
. (sum of service years) / employees in the
(8+13+15+3+13+28+4+12+4+26+29+3+10+3+17+13+15+15+23+13+12+1+14+14+17+16+7+27+18+24) /
(417 / 30)
= 13.9 years
= 14 years
The percentage of employees who have worked for atleast 10 years :
Number of employees with service years ≥ 10 years = 22 employees
Total number of employees
Percentage (%) = (22 / 30= * 100% = 0.7333 * 100% = 73.33% = 73%
Which atomic model states that it is impossible to know the exact location of electrons around the nucleus?
Answer:
Bohr Model is the correct answer
Answer:
Electron -Cloud Model
Explanation:
Just took the quiz got 100%
Which of the following statements is correct concerning the reaction 2 A + B → 2 C + 2 D?
1. The reaction is second-order overall
2. The reaction is third order overall
3. The rate is equal to k[A]²[B]
4. The rate is equal to k[A][B]
5. It cannot be determined given this information
Answer:
2.The reaction is third order overall
Explanation:
THIS ANSWER IS CORRECT
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I have an unknown volume of gas at a pressure of 0.50 atm and a temperature of 325 K. If I raise the pressure to 1.2 atm, decrease the temperature to 320 K, and measure the final volume to be 48 liters, what was the initial volume of the gas?
SHOW YOUR WORK
Answer:
the answer is 2.1 atm
Explanation:
the way people normally do it is by simply deciding the 325k with the 1.2
What occurs in endothermic reactions?
a) Heat energy is absorbed.
b) Water is produced.
c) Oxygen is produced.
d) Heat energy is released.
Answer:
a) Heat energy is absorbed.
Explanation:
What occurs in endothermic reactions?
a) Heat energy is absorbed. YES. This is the definition of an endothermic reaction.
b) Water is produced. NO. Endothermic refers to the heat absorbed and not to the products formed.
c) Oxygen is produced. NO. Endothermic refers to the heat absorbed and not to the products formed.
d) Heat energy is released. NO. This is known as an exothermic reaction.
the pressure of a sample of gas at constant volume is 942 kPa at 338K. what will the pressure be 293k?
Explanation:
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The position of the equilibrium for a system where K = 6.4 × 10 9 can be described as being favoring ________________
Answer:
to the right (products side)
Explanation:
The equilibrium constant K describes the ratio between the concentration of products and reactants at equilibrium. For a general reaction:
a A + b B → c C + d D
The equilibrium constant expression is:
[tex]K = \frac{[C]^{c} [D]^{d} }{[A]^{a} [B]^{b} }[/tex]
A low value of K indicates that the concentration of products (C and D) is low in relation with the concentration of reactants (A and B).
Conversely, a high value of K indicated that the concentration of products is high compared with the concentration of reactants.
Since K = 6.4 × 10⁹ is a high value, the concentration of products is higher than the concentration of reactants at equilibrium. Thus, the position of the equilibrium is favored to the right.
What is the density of Ar(g) at -11°C and 675 mmHg?
Answer:
The Density Of Ar (g) At -11°C And 675 MmHg (R =0.08206 L·atm/mol·K, 1 Atm = 760mmHg).
A 25.0 mL sample of a saturated C a ( O H ) 2 solution is titrated with 0.029 M H C l , and the equivalence point is reached after 37.3 mL of titrant are dispensed. Based on this data, what is the concentration (M) of the hydroxide ion?
Answer:
0.043 M
Explanation:
The reaction that takes place is:
Ca(OH)₂ + 2HCl → CaCl₂ + 2H₂OFirst we calculate how many HCl moles reacted, using the given concentration and volume required to reach the equivalence point:
0.029 M HCl * 37.3 mL = 1.0817 mmol HCl = 1.0817 mmol H⁺As 1 mol of H⁺ reacts with 1 mol of OH⁻, in the 25.0 mL of the Ca(OH)₂ sample there are 1.0817 mmoles of OH⁻.
With that in mind we can calculate the hydroxide ion concentration in the original sample solution, using the calculated number of moles and given volume:
1.0817 mmol OH⁻ / 25.0 mL = 0.043 MThe titration is termed the neutralization reaction with the acid and base. The concentration of hydroxide in the titration is 0.0865 M.
What is a neutralization reaction?The neutralization reaction is given as the reaction in which the acid and base react to form the salt and water, stabilizing the pH of the solution.
The neutralization of acid and base to identify the strength can be given as:
[tex]\rm M_V_1=M_2V_2[/tex]
Substituting the strength and the volume of calcium hydroxide and the HCl with the volume:
[tex]\rm 0.029\;M\;\times\;37.3\;mL=M_2\;\times\;25\;mL\\M_2=\dfrac{ 0.029\;M\;\times\;37.3\;mL}{25\;mL} \\M_2=0.0432\;M[/tex]
The strength of the calcium hydroxide in the reaction is 0.04326 M.
One molar unit of calcium hydroxide results in 2 molar units of hydroxide. The molar unit of hydroxide in 0.04326 M calcium hydroxide is:
[tex]\rm 1\;M\;Ca(OH)_2=2\;M\;OH^-\\\\0.04326\;M\;Ca(OH)_2=0.04326\;\times\;2\;M\;OH^-\\0.04326\;M\;Ca(OH)_2=0.0865\;M\;OH^-[/tex]
The concentration of hydroxide ion in the titration is 0.0865 M.
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Give the following reaction: ammonium nitrate—> dinitrogen monoxide + water.
a.) Write a complete balanced chemical equation.
b.) Calculate the number of molecules of water produced by 11.2g of ammonium nitrate
Answer:
a) NH₄NO₃ ⇒ N₂O + 2 H₂O
b) 1.69 × 10²³ molecules
Explanation:
Step 1: Write the balanced equation
NH₄NO₃ ⇒ N₂O + 2 H₂O
Step 2: Convert 11.2 g of NH₄NO₃ to moles
The molar mass of NH₄NO₃ is 80.04 g/mol.
11.2 g × 1 mol/80.04 g = 0.140 mol
Step 3: Calculate the moles of H₂O produced
0.140 mol NH₄NO₃ × 2 mol H₂O/1 mol NH₄NO₃ = 0.280 mol H₂O
Step 4: Calculate the number of molecules in 0.280 moles of water
We will use Avogadro's number.
0.280 mol × 6.02 × 10²³ molecules/1 mol = 1.69 × 10²³ molecules
1.rain pours from the sky
2.leaves of the plant dried
3.fluffy clouds form in the sky
4.bathing suit dries after swim
5.water puddles disappear
A.Evaporation
B.Condensation
C.Precipitation
D.Transpiration
Yan po pag pipilian
Answer:
1.Precipitation
2.Transpiration
3.Condensation
4.Evaporation
5.Evaporation
3.Condensation
Explanation:
Rain pours from the sky occurs due to the process of precipitation, leaves of the plant dried due to the process of transpiration in which the water is evaporated from the body of plant, fluffy clouds form in the sky occurs in the process of condensation, bathing suit dries after swim is due to evaporation in which water is removed and goes into the atmosphere and water puddles disappear due to the process of evaporation. Evaporation is the removal of water from the any surface whereas transpiration is the removal of water from plant body parts.
Sugar is added to water and initially completely dissolves, but eventually solid sugar collects on the bottom of the container. Sugar and water are ________partially miscible . This produces a dynamic equilibrium. Ethanol (a liquid) is added to water and only a single layer is observed no matter how much ethanol is added. Ethanol and water are__________
Answer: Sugar is added to water and initially completely dissolves, but eventually solid sugar collects on the bottom of the container. Sugar and water are both partially miscible. This produces a dynamic equilibrium. Ethanol (a liquid) is added to water and only a single layer is observed no matter how much ethanol is added. Ethanol and water are miscible.
Explanation:
When a substance (solute) dissolves partially in a solvent then it is known as partially miscible in the solvent. In such cases, a small amount of solute remains at the bottom of solution.
If a solute dissolves completely in solvent like water such that only one layer is seen in the solution then it means that the solute is miscible in solvent.
Thus, we can conclude that sugar is added to water and initially completely dissolves, but eventually solid sugar collects on the bottom of the container. Sugar and water are both partially miscible. This produces a dynamic equilibrium. Ethanol (a liquid) is added to water and only a single layer is observed no matter how much ethanol is added. Ethanol and water are miscible.
Gaseous methane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 9.6 g of methane is mixed with 64.9 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to significant digits.
Answer:
21.6 g
Explanation:
The reaction that takes place is:
CH₄ + 2O₂ → CO₂ + 2H₂OFirst we convert the given masses of both reactants into moles, using their respective molar masses:
9.6 g CH₄ ÷ 16 g/mol = 0.6 mol CH₄64.9 g O₂ ÷ 32 g/mol = 2.03 mol O₂0.6 moles of CH₄ would react completely with (2 * 0.6) 1.2 moles of O₂. As there are more O₂ moles than required, O₂ is the reactant in excess and CH₄ is the limiting reactant.
Now we calculate how many moles of water are produced, using the number of moles of the limiting reactant:
0.6 mol CH₄ * [tex]\frac{2molH_2O}{1molCH_4}[/tex] = 1.2 mol H₂OFinally we convert 1.2 moles of water into grams, using its molar mass:
1.2 mol * 18 g/mol = 21.6 gHow many grams of solute are present in 635mL of 0.450 M KBr?
Answer:
34.03 g
Explanation:
We'll begin by converting 635 mL to L. This can be obtained as follow:
1000 mL = 1 L
Therefore,
635 mL = 635 mL × 1 L / 1000 mL
635 mL = 0.635 L
Thus, 635 mL is equivalent to 0.635 L
Next, we shall determine the number of mole of the solute (KBr) in the solution. This can be obtained as follow:
Volume = 0.635 L
Molarity = 0.450 M
Mole of KBr =?
Mole = Molarity × Volume
Mole of KBr = 0.450 × 0.635
Mole of KBr = 0.286 mole
Finally, we shall determine the mass of 0.286 mole of KBr. This can be obtained as follow:
Mole of KBr = 0.286 mole
Molar mass of KBr = 39 + 80
= 119 g/mol
Mass of KBr =?
Mass = mole × molar mass
Mass of KBr = 0.286 × 119
Mass of KBr = 34.03 g
Thus, the mass of the solute (KBr) in the solution is 34.03 g
A cylinder contains 26.5 L of oxygen gas at a pressure of 1.7 atm and a temperature of 280 K. How much gas (in moles) is in the cylinder?
Answer:
The appropriate answer is "1.96 mol".
Explanation:
The given values are:
Volume,
V = 26.5 L
Pressure,
P = 1.7 atm
Temperature,
T = 280 K
Now,
The number of moles (n) will be:
= [tex]\frac{PV}{RT}[/tex]
By substituting the values, we get
= [tex]\frac{1.7\times 26.5}{0.0821\times 280}[/tex]
= [tex]\frac{45.05}{22.988}[/tex]
= [tex]1.96 \ mol[/tex]
Draw bond-line formulas of all dichloro derivatives that might be formed when 1-chloro-2,2,3,3,-tetramethylpentane is allowed to react with Cl 2 under UV irradiation. For each structure, indicate, with an asterisk, any stereocenters that might be present. Predcit the percentage of each product using the relative reactivities 3 0 = 5.3, 2 0 = 3.6, 1 0 = 1
Answer:
Explanation:
This is a halogenation reaction i.e substitution or replacement of a single or more than a single hydrogen atom in the organic alkane compound with the halogen(here it is chlorine).
The chlorination of 1-chloro-2,2,3,3-tetramethylpentane under UV light resulted in the formation of five (5) dichloro derivatives which are shown in the image attached below.
Also, the compounds containing a stereocenter (i.e a location within the compound composing of various substituents in which the interchangeability of these substituents has the tendency of resulting into a stereoisomer) are indicated with an asterisk in the image below.
From the image below:
compound 1 ⇒ 1,1-dichloro-2,2,3,3-tetramethylpentane = 2° C
∴
The given relative reactivity rate for 2° = 3.6x
For compound 2 ⇒ 1,4-dichloro-2,2,3,3-tetramethylpentane = 2° = 3.6x
For compound 3 ⇒ 1,5-dichloro-2,2,3,3-tetramethylpentane = 1° = 1x
For compound 4 ⇒ 1-chloro-2-chloromethyl-2,3,3-trimethylpentane
= 1° = 1x
For compound 5 ⇒ 1-chloro-3-chloromethyl-2,2,3-trimethylpentane
= 1° = 1x
As such, we have:
2(3.6x) + 3(1x) = 100
7.2x + 3x = 100
10.2x = 100
x = 100/10.2
x = 9.803°
∴
For compound (1) = 3.6(9.803) = 35.3%
For compound (2) = 3.6(9.803) = 35.3%
For compound (3) = 1(9.803) = 9.803°%
For compound (4) = 1(9.803) = 9.803°%
For compound (5) = 1(9.803) = 9.803°%
The angular momentum quantum number (l) value of 0 indicates the ________ subshell.
Answer:
indicates the number of subshells
In order for a substitution reaction to take place, at a minimum, __________ and ___________ are needed. carbocation rearrangement proton transfer loss of a leaving group nucleophilic attack
Answer: In order for a substitution reaction to take place, at a minimum, loss of a leaving group and nucleophilic attack are needed.
Explanation:
When one group in a molecule is replaced by another one then it is called a substitution reaction.
For a substitution reaction reaction to occur at a minimum, it is necessary to have a leaving group that helps in creating a carbocation and hence a nucleophile can easily attack.
For example, [tex]CH_{4} + Cl_{2} + h\nu \rightarrow CH_{3}Cl + HCl[/tex]
Thus, we can conclude that in order for a substitution reaction to take place, at a minimum, loss of a leaving group and nucleophilic attack are needed.
classify each of the following as a pure substance or a mixture.
a) baking soda
b) ice
c)blueberry muffin
d) zink
Answer:
c
Explanation:
its c because it has multiple mixture blueberries flower water and others thats why i says c
A soluble unknown has contaminated your sample. It absorbs the same wavelength as your analyte, Allura Red dye. How will this affect your results, and what type of error is introduced
Answer:
The explanation as per the given query is presented in the following paragraph.
Explanation:
The Allura Reds Pigment or coloring increases the absorption by absorbing at around a very similar wavelength as that of the analysis.Therefore, the approximated analysis concentration or its intensity seemed substantially higher than that of the authentic one. Some positive mistake is going to exist.Thus the above is the correct explanation.
The measured absorbance will be higher, thereby creating systematic error.
Absorbance can be defined as the value or quantity of light absorbed by a given sample.The presence of impurity with a similar absorption wavelength will increase the absorbance. Moreover, systematic error is a type of error that is repeated along with different processes of measurement.In conclusion, the measured absorbance will be higher, thereby creating systematic error.
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Methanal is the simplest aldehyde, with one carbon atom. Draw the structural model for methanal (using C and H).
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Draw the structural model for methanal (using C and H and O).
[tex] \huge\mathbb{\red A \pink{N}\purple{S} \blue{W} \orange{ER}}[/tex]
First place the C and then make a double bonded O atom with it then fill H to complete all valence spaces
Which of the following was NOT explained by Dalton's atomic theory?
ANSWER:
A. the Law of Multiple Proportions
B. the difference between elements and compounds
C.?the difference between isotopes of an element
D. the Law of Conservation of Mass
Answer:
A. the Law of Multiple Properties
Answer:
A. the law of multiple proportions
A. Directions:Describe ways on how to protect humans and plants and animals Choose your answer in the box and fill in the concept map below
Answer:
i) Humans - drinks lot of water
- use umbrella
- use hats and sunglasses
- apply sunblock when swimming
- wear rush guard
ii) Plants - water the plants
-put a shade on the plants
iii) Animals - provide pets with plenty of water
- place the animals under the tree during noon time
Which is a nervous system test?
Answer:
Sorry, is there supposed to be an attachment, If so kindly republish your Question.
A chemist measures the amount of iodine solid produced during an experiment. He finds that of iodine solid is produced. Calculate the number of moles of iodine solid produced. Round your answer to significant digits.
The question is incomplete, the complete question is:
A chemist measures the amount of iodine solid produced during an experiment. He finds that 8.31 g of iodine solid is produced. Calculate the number of moles of iodine solid produced. Round your answer to the correct number of significant digits.
Answer: The number of moles of solid iodine produced is 0.0327 moles
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given mass of solid iodine = 8.31 g
Molar mass of solid iodine = 253.8089 g/mol
Plugging values in equation 1:
[tex]\text{Moles of solid iodine}=\frac{8.31g}{253.8089g/mol}=0.0327mol[/tex]
Hence, the number of moles of solid iodine produced is 0.0327 moles
For each of the following changes at equilibrium, indicate whether the equilibrium shifts in the direction of products, reactants, or does not change: CaCO3(s)+heat⇌CaO(s)+CO2(g)
1) increasing the temperature
shifts equilibrium in the direction of the reactants
does not change
shifts equilibrium in the direction of the products
2) decreasing the volume of the container
shifts equilibrium in the direction of the reactants
shifts equilibrium in the direction of the products
does not change
3) adding a catalyst
shifts equilibrium in the direction of the reactants
shifts equilibrium in the direction of the products
does not change
4) adding more CaO(s)
does not change
shifts equilibrium in the direction of the reactants
shifts equilibrium in the direction of the products
Answer:
shifts equilibrium in the direction of the products
shifts equilibrium in the direction of the reactants
does not change
shifts equilibrium in the direction of the reactants
Explanation:
When a constraint such as a change in pressure, concentration or temperature is imposed on a reaction system in equilibrium, the equilibrium position will shift in such a way as to annul the constraint.
The reaction is endothermic as written. Hence, increase in temperature increases the rate of forward reaction thereby shifting the equilibrium position towards the products.
When the volume of a reaction is decreased, the equilibrium position shifts in the direction which produces the least total volume. In this case, decrease in volume shifts the equilibrium position towards the reactants.
A catalyst has no effect on the equilibrium position. However, a catalyst may cause equilibrium to be achieved faster or at a lower temperature.
When more CaO is added, the equilibrium position shifts towards the reactants side and more CaCO3 is produced.