Identify the isoelectronic elements.
i. Cl-, F-, Br-, I-, At-
ii. Ne, Ar, Kr, Xe, He
iii. N3-, S2-, Br-, Cs+, Sr2+
iv. N3-, O2-, F-, Na+, Mg2+
v. Li+, Na+, K+, Rb+,Cs+
Answer:
iv. N³⁻, O²⁻, F⁻, Na⁺, Mg²⁺
Explanation:
Isoelectronic elements are those that have the same number of electrons. So, if at least 2 elements differ in their number of electrons, the series is not of isoelectronic elements.
To know the number of electrons we will consider the atomic number and add electrons if it is an anion and subtract electrons it is a cation.
Identify the isoelectronic elements.
i. Cl⁻, F⁻, Br⁻, I⁻, At⁻. NO. Cl⁻ has 18 electrons (17+1) and F⁻ has 10 electrons (9+1). ii. Ne, Ar, Kr, Xe, He. NO. Ne has 10 electrons and Ar has 18. iii. N³⁻, S²⁻, Br⁻, Cs⁺, Sr²⁺. NO. N³⁻ has 10 electrons (7+3) and S²⁻ has 18 (16+2).iv. N³⁻, O²⁻, F⁻, Na⁺, Mg²⁺. YES. They all have 10 electrons v. Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺. NO. Li⁺ has 2 electrons (3-1) and Na⁺ has 10 (11-1).What size volumetric flask would you use to create a 1.00M solution using 166.00 g of KI?
Answer:
A 1 liter volumetric flask should be used.
Explanation:
First we convert 166.00 g of KI into moles, using its molar mass:
Molar mass of KI = Molar mass of K + Molar mass of I = 166 g/mol
166.00 g ÷ 166 g/mol = 1 mol KIThen we calculate the required volume, using the definition of molarity:
Molarity = moles / litersLiters = moles / molarity
1 mol / 1.00 M = 1 LA student collecting CaCO3 produced by the reaction of Na2CO3(aq) and CaCl2(aq) obtains a percent yield of 81%. Choose all of the following observations that could explain the low yield.
a. The combined reactants were not stirred before filtering the precipitate.
b. The student did not completely dry the precipitate before weighing it.
c. The precipitate was not washed prior to drying.
d. A rubber policeman was not used to scrape precipitate from the beaker.
e. The filter paper was not wetted with water prior to filtering the precipitate.
Answer:
a, d and e. are true.
Explanation:
The reaction that occurs is:
Na2CO3(aq) + CaCl2(aq) → CaCO3(s) + 2NaCl
In ideal conditions, the percent yield of the reaction must be 100%. All explanations about why the student could not collect all precipitate are right:
a. The combined reactants were not stirred before filtering the precipitate. Not stirring could not promote all the reaction. TRUE.
b. The student did not completely dry the precipitate before weighing it. If the student don't dry the precipitate, the mass of precipitate must be higher producing a percent yield > 100%. FALSE.
c. The precipitate was not washed prior to drying. Produce more mass. FALSE.
d. A rubber policeman was not used to scrape precipitate from the beaker. If the student doesn't collect all the precipitate the percent yield could be < 100%.. TRUE.
e. The filter paper was not wetted with water prior to filtering the precipitate. TRUE. If you don't wet the filter paper you can lose a part of precipitate from the walls of this one.
4. After reaching the final titration endpoint the solution will be cloudy white. As time goes on the solution will turn back to a cloudy dark purple color. Why does this occur if you have already reached the endpoint
Answer: hello some part of your question is missing below is the missing part
In an experiment to determine the % of ascorbic acid in Vitamin C Tablets by Titration with Potassium Bromate,
answer:
Oxidation half reaction of Vitamin C
Explanation:
The solution will turn cloudy dark purple even after reaching endpoint when allowed to settle with time. because of the Oxidation half reaction of Vitamin C. also during the Titration process few drops of starch solution will be added to help determine the endpoint of the experiment .
Compare the solubility of silver chloride in each of the following aqueous solutions:
a. 0.10 M AgNO3 More soluble than in pure water.
b. 0.10 M NaCI Similar solubility as in pure water
c. 0.10 M KNO3 Less soluble than in pure water.
d. 0.10 M NH4CH3COO
Answer:
Compare the solubility of silver chloride in each of the following aqueous solutions:
a. 0.10 M AgNO3 More soluble than in pure water.
b. 0.10 M NaCI Similar solubility as in pure water
c. 0.10 M KNO3 Less soluble than in pure water.
d. 0.10 M NH4CH3COO
Explanation:
This is based on common ion effect.
According to common ion effect, the solubility of a sparingly soluble salt decreases in a solution containing common ion to it.
The solubility of AgCl(s) is shown below:
[tex]AgCl(s) <=> Ag^{+}(aq)+Cl^-(aq)[/tex]
So, when it is placed in:
a. 0.10 M AgNO3
Due to common ion effect Ag+, its solubility is less in this solution than in pure water.
b. 0.10 M NaCI :
Due to common ion effect Cl-, its solubility is less in this solution than in pure water.
c. 0.10 M KNO3 :
In this solution there is no presence of common ion.
So, the solubility of AgCl in this solution is similar to that of pure water.
d. 0.10 M NH4CH3COO:
In this solution, AgCl forms a precipitate.
So, the solubility of AgCl is more in this solution compared to pure water.
How do we fix climate change?
The biggest problem of course is conspiracy theorys. Some say it is just a hoxe when really their chidrin or grandchidrin will sufer greatly from it. How do we educate ourselfs better?
Answer:
Hi so your answer is that to helping fix the climate change you have to : speak up , power your home with renewable engery , reduce water waste , dont waste food , and finally invest energy .
Explanation:
Really hope i helped , have a nice day :)
Answer:
we can reduce air pollution,which is one of the main cause of climate change.Climate change is not a hoxe if it is not attending the upcoming generations will suffer greatly.
What would happen to the Earth's hydrosphere if there were no atmosphere?
What is the speed of a wave with a frequency of 2 Hz and a wavelength of 87m (subject is science) pls answer fast
Answer:
43.5
Explanation:
Hope that helps
How do enzymes function in biological reactions?
Answer:
it binds molecules like a chemical bond-breaking
Explanation:
Enzymes perform the critical task of lowering a reaction's activation energy—that is, the amount of energy that must be put in for the reaction to begin. Enzymes work by binding to reactant molecules and holding them in such a way that the chemical bond-breaking and bond-forming processes take place more readily.
Consider the following events that take place when rip currents occur.
A. Waves travel to the beach.
B. Waves are trapped by the sandbars.
C. Waves reach the shore and go back to the ocean.
D. Waves speed up and flow between the sandbars.
E. Waves are broken by the sandbars.
Which list shows the order of events in the production of rip currents?
How many milliliters of a 0.40%(w/v) solution of nalorphine must be injected to obtain a dose of 1.5 mg?
Answer:
0.375mL of solution of nalorphine must be injected
Explanation:
A solution of 0.40% (w/v) contains 0.40g of solute (In this case, nalorphine), in 100mL of solution. To obtain 1.5mg of nalorphine = 1.5x10⁻³g of nalorphine are needed:
1.5x10⁻³g * (100mL / 0.40g) =
0.375mL of solution of nalorphine must be injectedA 14.570 g sample of CaCl2 was added to 12.285 g of K2CO3 and mixed in water. A 3.494 g yield of CaCO3 was obtained.
What is the limiting reagent?
-CaCO3
-K2CO3
-CaCl2
Calculate the percent yield of CaCO3.
yield of CaCO3= %
Answer:
Limiting reagent is the potassium carbonate.
Percent yield of calcium carbonate is: 39.3 %
Explanation:
The reaction is:
CaCl₂ + K₂CO₃ → CaCO₃ + 2KCl
Formula for percent yield is:
(Produced yield / Thoeretical yield) . 100
Firstly we determine the moles of each reactant, in order to say what is the limiting reagent: ratio is 1:1.
1 mol of chloride need 1 mol of carbonate.
14.570 g . 1 mol /110.98 g = 0.131 moles of CaCl₂
12.285 g . 1 mol / 138.2g = 0.0889 moles of carbonate.
Limiting reagent is carbonate. For 0.131 moles of CaCl₂ we need the same amount of carbonate and we have less moles.
Ratio is also 1:1, with calcium carbonate.
1 mol of potassium carbonate produces 1 mol of calcium carbonate
then, 0.0889 moles will produce the same amount of CaCO₃
We convert moles to mass: 0.0889 mol . 100.08g /mol = 8.89 g
That's the theoretical yield; to find the percent yield:
(3.494 g / 8.89g) . 100 = 39.3%
Toothpastes containing sodium hydrogen carbonate (sodium bicarbonate) and hydrogen peroxide are widely used. Write Lewis structures for the hydrogen carbonate ion and hydrogen peroxide molecule, with resonance forms where appropriate.
Answer:
See explanation and images attached
Explanation:
The first image shows the structure of hydrogen peroxide. It does not exist as resonance structures. The structure and properties of the molecule can wholly be explained on the basis of a single Lewis structure.
However, the structure of the bicarbonate ion in sodium bicarbonate can not be completely described by a single Lewis structure. Hence, two resonance structures are shown for the bicarbonate ion. In each case, Na^+ is the counter ion.
Help me please , I got 0.003 for a I need help with b and c
Answer:
(a) The moles of CuSO₄ is 3.125 × 10⁻³ moles.
(b) The moles of Cu is 3.125 × 10⁻³ moles.
(c) The mass of Cu is 0.2 g.
Explanation:
Given:
Mass of CuSO₄ = 0.5 g
Molar mass of CuSO₄ = 160 g/mol
The given balanced chemical equation is:
[tex]2Al+3CuSO_4\rightarrow 3Cu+Al_2(SO_4)_3[/tex]
Part (a):
Calculating the moles of CuSO₄.
[tex]\text{Moles of } CuSO_4=\frac{\text{Mass of }CuSO_4}{\text{Molar mass of }CuSO_4}\\\\\text{Moles of } CuSO_4=\frac{0.5g}{160g/mol}\\\\\text{Moles of } CuSO_4=3.125\times 10^{-3}mol[/tex]
Thus, the moles of CuSO₄ is 3.125 × 10⁻³ moles.
Part (b):
Calculating the moles of Cu.
From the balanced chemical equation, we conclude that:
As, 3 moles of CuSO₄ reacts to give 3 moles of Cu
So, 3.125 × 10⁻³ moles of CuSO₄ reacts to give 3.125 × 10⁻³ moles of Cu
Thus, the moles of Cu is 3.125 × 10⁻³ moles.
Part (c):
Calculating the mass of Cu.
Mass of Cu = Moles of Cu × Molar mass of Cu
Molar mass of Cu = 64 g/mol
Mass of Cu = (3.125 × 10⁻³ mole) × (64 g/mol)
Mass of Cu = 0.2 g
Thus, the mass of Cu is 0.2 g.
The formula for europium oxide is Eu203. On the basis of this information, the formula for the chlorate of europium would be expected to be
Answer:
Eu(ClO3)3
Explanation:
The chlorate ion is written as follows, ClO⁻ ₃. We can see from this that the ion is univalent.
From the formula, Eu203, it is easy to see that the europium ion is trivalent.
Hence, when a compound is formed between the europium ion and chlorate ion, the compound will be written as Eu(ClO3)3.
This is so because, when ionic compounds are formed, there is an exchange of valence between the ions in the compound. This gives the final formula of the ionic substance.
What is the IUPAC name for this organic molecule?
Answer:
2–methylbutane
Explanation:
To name the compound given above, the following must be obtained:
1. Determine the longest continuous carbon chain. This gives the parent name of the compound.
2. Determine the substituent group attached.
3. Determine the position of the substituent group by giving it the lowest possible count..
4. Combine the above to obtain the name of the compound.
With the above information, we can name the compound as follow:
1. The longest continuous carbon chain of the compound is 4. Thus, the parent name is butane.
2. The substituent group attached to the compound is methyl (–CH₃).
3. The methyl (–CH₃) group is located at carbon 2 (i.e counting from the left side).
4. The name of the compound is:
2–methylbutane
Give the balanced equation for the neutralisation of the excess NaOH with HCI.
1 NaCl + 1 HCl ➡️ 1 NaCl + Water (H2O) .
Predict the products from theses reaction, and balance the equations. Include phase symbols.
Reaction : K(s)+Cl2(g)⟶
Reaction :Cu(s)+O2(g)⟶
Answer:
2 K(s) + Cl₂(g) ⟶ 2 KCl(s)
2 Cu(s) + O₂(g) ⟶ 2 CuO(s)
Explanation:
Both reactions are synthesis reactions (two substances combine to form another).
Reaction: K(s) + Cl₂(g) ⟶
The product is the binary salt KCl. The balanced chemical equation is:
2 K(s) + Cl₂(g) ⟶ 2 KCl(s)
Reaction: Cu(s) + O₂(g) ⟶
The most likely product is the metal oxide CuO. The balanced chemical equation is:
2 Cu(s) + O₂(g) ⟶ 2 CuO(s)
study the reaction given below in which excess magnesium ribbon (Mg)reacts with 50cm of a diluted sulphuric acid solution at room temperature
Questions
what Changes can be made to the following substance to increase the rate of reaction?
5.1.1 Magnesium
5.1.2 Sulphuric acid
Answer:
Magnesium reacts with dilute hydrochloric acid in a conical flask which is ... One student can add the magnesium ribbon to the acid and stopper the flask, ... 50 cm3 of 1M hydrochloric acid is a six-fold excess of acid.
Propose two steps that could be taken to reduce the vulnerability of the US to hurricanes. Explain why you think those would be effective in saving lives and property.
This is not just about planning and design of buildings and towns/cities, even though those are very important. You could write about the role of research in science and technology and their contributions to emergency preparedness.
You must write at least one paragraph (roughly 150 words).
Answer:
Sensors and evacuation planning.
Explanation:
Sensors that provides information about hurricane and evacuation planning are the two steps that can reduce the vulnerability of the United States to hurricanes. Sensors provides information about hurricane so we can prepare ourselves about it and the evacuation plan helps in order to quick displacement of people from the hurricane area so these two steps can reduce the vulnerability of the US to hurricanes.
When H2S(g) reacts with O2(g) to form H2O(g) and SO2(g), 124 kcal of energy are evolved for each mole of H2S(g) that reacts. Write a balanced equation for the reaction with an energy term in kcal as part of the equation.
Answer:
2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g) + 248kcal
Explanation:
The reaction of the problem occurs as follows:
H2S(g) + O2(g) → H2O(g) + SO2(g)
To balance the reaction we must balance oxygens:
H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g)
To balance the complete reaction:
2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g)
As the energy is evolved, 124kcal are as product in the reactio per mole of H2S. As the balanced reaction contains 2 moles of H2S, the heat evolved is:
124kcal*2 = 248kcal:
2H2S(g) + 3O2(g) → 2H2O(g) + 2SO2(g) + 248kcal
And this is the balanced equation
What is the observation of heating of iodine crystals
Answer:
On heating, the van der Waals dispersion forces existing then will easily break as it has a low boiling point and sublimates into gas. On heating iodine in the test tube, iodine evolves as violet fuming gas.
Explanation:
A student named a particular compound 2-ethyl-3-methyl-2-butene. Assuming that the student's choice actually corresponded to the correct distribution of the double bond and the substituents, what is the correct IUPAC name for this compound
Answer:
2-ethyl-3-methylbut-2-ene
Explanation:
The whole idea of IUPAC nomenclature is to devise a universally accepted system of writing the name of a compound from its structure.
According to IUPAC nomenclature, the root of the compound is the longest carbon chain. The substituents are named in alphabetical order and in such a way as to give each one the lowest number. The position of the functional group is indicated accordingly.
For the compound in question, its correct IUPAC name is 2-ethyl-3-methylbut-2-ene.
A recipe calls for 1/4 cup of butter. One ounce (oz) of butter is equivalent to 2 tablespoons (T), and there are 8 oz of butter in 1 cup. Which of the following statements correctly interpret the information provided?
a. The information provided gives the conversion factor 8oz/2T.
b. The information provided gives the conversion factor 8oz/1 cup.
c. The recipe requires 64 T of butter.
d. The recipe requires 4T of butter.
Answer:
D
Explanation:
8oz=1cup
Xoz=1/4cup
cross multiply
Xoz=8×1/4=2
2oz=1/4cup
1oz=2T
2oz=x
cross multiply
×=2×2=4T
The cup of butter, number of tablespoons and ounces of butter are all in direct proportion with one another. The interpretation of the information provided is:
(b). The information provided gives the conversion factor 8oz/1 cup.
Given that:
[tex]1\ recipe = \frac{1}{4}\ cup[/tex]
[tex]1\ oz = 2T[/tex]
[tex]8\ oz = 1\ cup[/tex]
Multiply both sides of [tex]1\ oz = 2T[/tex] by 8
[tex]8 \times 1oz = 8 \times 2T[/tex]
[tex]8 oz = 16T[/tex]
Substitute 8oz for 1 cup in: [tex]1\ recipe = \frac{1}{4}\ cup[/tex]
[tex]1\ recipe = \frac{1}{4} \times 8oz[/tex]
Substitute [tex]8 oz = 16T[/tex]
[tex]1\ recipe = \frac{1}{4} \times 16T[/tex]
[tex]1\ recipe = 4T[/tex]
The interpretations are as follows:
[tex]1\ recipe = 4T[/tex] means that 1 recipe requires 4T of butter [tex]8\ oz = 1\ cup[/tex] means that the information provided gives a conversion of 8oz/1 cupHence, (b) is correct
Read more about direct proportions at:
https://brainly.com/question/1266676
list some applications of chemistry in your dail life
Chemistry and chemical reactions are not just limited to the laboratories but also the world around you.
Chemistry in Food Production:
Plants produce food for themselves through photosynthesis; which is a complex chemical reaction in itself. The chemical reaction that takes place in photosynthesis is the most common and vital chemical reaction.
6 CO2 + 6 H2O + light → C 6H12O6 + 6 O2
Chemistry in Hygiene:
Right before you consume your food, you make it a point to wash your hands with soap. Isn’t it? The cleaning action of soap is based on its ability to act as an emulsifying agent. Soaps are fatty acids salts of sodium or potassium; produced by a chemical reaction called saponification. Soaps interact with the grease or oil molecule, which, in turn, results in a cleaner surface.
The Chemistry of an Onion:
Ever wondered why you shed tears while chopping an onion? This also happens because of the underlying chemistry concepts. As soon as you slice an onion, sulfenic acid is formed from amino acid sulfoxides. Sulfenic acid is responsible for the volatile gas, propanethiol S-oxide, that stimulates the production of tears in the eyes.
Chemistry in Baking:
Who does not like to eat fluffy freshly baked bread? Baking soda is an efficient leavening agent. The addition of baking soda to food items before cooking leads to the production of carbon dioxide (CO2); which causes the foods to rise. This whole process of rising of baked good is called chemical leavening.
Chemistry in Food Preservatives:
In case you ever read the ingredients on the bottle of ketchup, jams or pickles, you might be surprised to see a never-ending list of chemicals. What are they? These chemicals are called food preservatives; which delay the growth of microorganisms in foods. The chemical food preservatives not only prohibit the growth of bacteria, virus, fungi but also hinder the oxidation of fats, which is responsible for making the foods rancid. The most common chemical food preservatives are sodium benzoate, sorbic acid, potassium sorbate, calcium sorbate, sodium sorbate, propionic acid, and the salts of nitrous acid.
Chemistry in Digestion
The moment you put food in your mouth, a number of different chemical reactions start in your digestive tract. Saliva contains the enzyme amylase, which is responsible for breaking down carbohydrates, the stomach starts producing hydrochloric acid, the liver releases bile and the list of compounds released during digestion goes on. How do they work? All these enzymes undergo chemical reactions so that proper digestion, as well as assimilation of the food, occurs.
The Working of a Sunscreen
Before going out on a sunny day, you make it a point to wear sunscreen. Even the principle, behind the working of a sunscreen, has a chemistry background. The sunscreen uses a combination of organic and inorganic compounds to act as a filter for incoming ultraviolet rays. Sunblocks, on the other hand, scatter away UV light; so that it is unable to penetrate deep into the skin. Sunblocks contain complex chemical compounds like zinc oxide or titanium oxide, which prevent the UV rays to invade deeper into the skin.
Chemistry in Rust Formation
With time, your iron instruments start developing an orange-brown flaky coating called rust. The rusting of iron is a type of oxidation reaction. The atoms in the metal iron undergo oxidation and reduction; causing rusting. The formation of verdigris on copper and the tarnishing of silver are also the other everyday examples of chemical reactions. The chemical equation underlying rusting is:
Fe + O2 + H2O → Fe2O3. XH2O
Hope it helps.
You decide to share some sugar sweetened fruit juice with your friend. You divide the fruit equally into two glasses. Then an additional equal volume of water is added to glass 1. Which glass would have the lower molarity?
Answer:
Glass 1
Explanation:
Molarity is measured in moles of substance per liter.
For the sake of calculations, let's say that each glass contains 1 mole of juice and 1 liter after it is divided between the glasses. If you add an equal amount of water to glass 1 ( another liter), you now have:
Glass 1 = 1 mole / 2 liters = 0.5 M
Glass 1 = 1 mole/ 1 liter = 1 M
So glass 1 will have a lower molarity
Which best expresses the uncertainty of the measurement 32.23 cm?
A.) ±0.05 cm
B.) 0.1 cm
C.) 1%
D.) ±0.01 cm?
Answer:
D.) ±0.01 cm?
Explanation:
Since 32.23 cm has two decimal places, the uncertainty is taken as one-half the last decimal pace.
The last decimal place is 0.03. Half of this is 0.03 cm/2 = 0.015 cm.
Since we cannot go below two decimal places, we ignore the 5 in 0.015 cm.
So, we have our uncertainty as 0.01 cm.
So, the best expression of the uncertainty in the measurement 32.23 cm is ± 0.01 cm.
So, the answer is D. which is ± 0.01 cm.
PLZZZ HELPPPPPPPPPPPPPPPP
Andy needs to determine the freezing point depression of 30.0 mL of 0.50 m AlCl3 aqueous solution. When dissolved, AlCl3 dissociates into Al3 and Cl-. Andy realizes that he may need to reduce the effect of ion-pairing in his 0.50 m AlCl3 aqueous solution. Which of the following would reduce the ion-pairing effect in his AlCl3 solution?A. Add some solid AICIz to his solution.B. Add some water to his solution.C. Use only half of his initial volume.D. Use 45 mL of the 0.50 m AlCl3 solution.
Answer:
Add some water to his solution
Explanation:
Ion pair effect refers to strong electrostatic interaction between oppositely charged ions in solution. Such strong interaction affects solute- solvent interaction when an ionic substance is dissolved in water.
High solute concentration may lead to ion-pair effect. Hence, the ion pair effect may be minimized by adding more water (decreasing the concentration of the solution).
To reduce the ion- pair effect, Andy needs to add some water to his solution (dilution).
The activity that would reduce the ion-pairing effect in his AICI₃ solution is : ( B ) add some water to his solution
Ion pair effectIon pair effect is a strong electrostatic interaction seen between ions with opposite charges, when an ionic substance is been dissolved in a solvent such as water this effect will affect the dissolution of the substance.
High concentration of the solute in a solution also leads to the ion pair effect therefore for Andy to reduce the ion-pairing effect in his solution he has to add more water to reduce the concentration of the solute.
Hence we can conclude that The activity that would reduce the ion-pairing effect in his AICI₃ solution is to add some water to his solution
Learn more about ion pair effect : https://brainly.com/question/24100697
A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies one on top of the other on Earth's surface, how far would the stack extend (in kilometers). For comparison, the sun is about 150 million km from Earth and the nearest star (Proxima Centauri) is about 40 trillion km from Earth].
Answer:
6.02 × 10²⁷ km
Explanation:
Step 1: Calculate the height of the stack of pennies
A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies (6.02 × 10²³ pennies) one on top of the other on Earth's surface, the height of the stack of pennies would be:
6.02 × 10²³ pennie × 1.0 mm/1 pennie = 6.02 × 10²³ mm
Step 2: Convert 6.02 × 10²³ mm to kilometers
We will use the following conversion factors.
1 km = 10³ m1 m = 10³ mm6.02 × 10²³ mm × 1 m/10³ mm × 1 km/10³ m = 6.02 × 10²⁷ km
