Answer:
-2
Explanation:
10 ÷ (-5) = -2
What changes occur in the sky over the period of 24 hours? Why do these changes occur?
Answer:
Orientation
Explanation:
Which number is the same as 2.5
10-3?
The number that is the same as the exponentiation given as follows: 2.5 × 10-³ is 0.0025.
What is exponentiation?Exponentiation is the process of calculating a power by multiplying together a number of equal factors, where the exponent specifies the number of factors to multiply.
For example, if 10 is multiplied three times, then it can be written as "10 raised to 3" which means 10³. In this case, 10 is the base, and 3 is the exponent.
Therefore, a number 0.0025 can be written in exponentiation as 2.5 × 10-³ by counting the number of zeros forward.
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what complex do copper sulfate and sodium hydroxide form
Answer: copper hydroxide
Explanation:
Copper(II) hydroxide is the hydroxide of copper with the chemical formula of Cu(OH)2. It is a pale greenish-blue or bluish-green solid. Some forms of copper(II) hydroxide are sold as "stabilized" copper(II) hydroxide, although they likely consist of a mixture of copper(II) carbonate and hydroxide.
Example:
2NaOH+CuSO4→Na2SO4+Cu(OH)2
An error during which cellular process would create a gene mutation?
An error during DNA replication would create a gene mutation.
During DNA replication, the genetic information in a cell is copied to make new DNA molecules. However, mistakes can occur during this process, leading to changes in the DNA sequence, which can result in a mutation. Mutations can also be caused by exposure to environmental factors, such as radiation or chemicals, which can damage the DNA molecule directly or affect the cellular processes involved in DNA replication.
Mutations can have a variety of effects on the organism, ranging from no effect to causing serious health problems or even death. Gene mutations can also be inherited from a parent, which can result in genetic disorders or predisposition to certain diseases. Therefore, it is important to understand the mechanisms of gene mutations and their potential impacts on organisms.
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Will y’all find this answer real quick for me !!
The mass (in grams) of sodium carbonate, Na₂CO₃ required to produce 85 grams of barium carbonate, BaCO₃ is 45.7 grams
How do i determine the mass of sodium carbonate, Na₂CO₃ required?First, we shall observe the balanced equation to obtain useful information. This is shown below:
Na₂CO₃ + BaSO₄ -> BaCO₃ + Na₂SO₄
Molar mass of BaCO₃ = 197 g/molMass of BaCO₃ from the balanced equation = 1 × 197 = 197 g Molar mass of Na₂CO₃ = 106 g/molMass of Na₂CO₃ from the balanced equation = 1 × 106 = 106 gFrom the balanced equation above,
197 g of BaCO₃ were obtained from 106 g of Na₂CO₃
With the above information, we can obtain the mass of sodium carbonate, Na₂CO₃ required to produce 85 grams of barium carbonate, BaCO₃. This is illustrated below:
From the balanced equation above,
197 g of BaCO₃ were obtained from 106 g of Na₂CO₃
Therefore,
85 g of BaCO₃ will be obtain from = (85 × 106) / 197 = 45.7 g of Na₂CO₃
Thus, we can conclude from the above calculation that the mass of sodium carbonate, Na₂CO₃ required is 45.7 grams
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Does 7period element experience inert pair effect? And why
Yes, elements in the 7th period of the periodic table can experience the inert pair effect. The inert pair effect is observed when the valence s-electrons of heavier elements (particularly in Groups 13-15) are less likely to participate in chemical bonding compared to their p-electrons.
This effect becomes more pronounced as you move down the periodic table.In the 7th period, elements such as polonium (Po), astatine (At), and tennessine (Ts) exhibit the inert pair effect. This is due to the increasing size of the atoms and the relativistic effects that come into play at higher atomic numbers.
The increased size and relativistic effects cause the s-electrons to be more strongly influenced by the attractive force of the positively charged nucleus, making them less available for bonding.
As a result, elements experiencing the inert pair effect tend to exhibit oxidation states lower than what might be expected based on their position in the periodic table. This effect has significant implications for the chemical behavior and reactivity of these elements.
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Describe the steps needed to take in order to successfully calculate the concentration of a solution from a titration lab.
Plsss help
The steps are;
Determine the titration reaction equation
Perform the titration
Record the data
Calculate the concentration
Titration labFind the chemical equation for the reaction that takes place during the titration.
Swirl or stir the analyte solution continually as you gradually add the titrant from the burette. An indication may be used to pinpoint the reaction's endpoint once the titrant and analyte react.
To calculate the amount of titrant utilized in the reaction, take note of the initial and final burette readings. To calculate the ratio between the titrant and the analyte, use the stoichiometry of the balanced chemical equation.
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27. Which is true about scientific theories? (2 points)
They are the result of a single experiment.
They are the results of many experiments over a long period of time.
O They are proposed by scientists who wish to investigate a new topic.
They are only based on the most recent evidence.
Answer:
hey are the results of many experiments over a long period of time.
Explanation:
What information about a representative element can you get from just knowing its group number?
the number of electrons it has in the highest occupied energy level
the total number of electrons it has
the number of filled energy levels it has
the number of protons and neutrons it has in the nucleus
You can determine the number of electrons it has in the highest occupied energy level. Option A
Representative elements are found in Groups 1, 2, and 13-18 of the periodic table. The group number corresponds to the number of valence electrons, which are the electrons in the outermost energy level.
For example, elements in Group 1 have one valence electron, while elements in Group 18 have eight valence electrons (except helium, which has two). Knowing the group number helps predict the element's chemical properties, as valence electrons play a significant role in chemical reactions and bonding.
Information regarding the total number of electrons (B), the number of filled energy levels (C), and the number of protons and neutrons in the nucleus (D) cannot be determined from just the group number.
However, you can use the element's atomic number and electron configuration to find this information. The atomic number represents the total number of protons and electrons in an atom, while electron configuration illustrates the distribution of electrons in energy levels. Option A
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Hydroxides (oh-) are insoluble except for
Answer:
LiOH is soluble. Na2CO3 is soluble. Cu(OH)2 is insoluble.
Explanation:
LiOH is soluble. Na2CO3 is soluble. Cu(OH)2 is insoluble.
I need help with this please fast
4) The volume of the HCl used is 9.500 mL while the volume of the NaOH used is 3.800 mL.
5) Molarity of sodium hydroxide is obtained from; Molarity of HCl * 1/2
What is titration?By reacting an unknown component with a known quantity of a different chemical known as a titrant, titration is a laboratory procedure used to measure the concentration of an unknown substance, often a solute dissolved in a liquid.
The endpoint of a titration can be detected in a number of ways, depending on the specific titration being performed.
4)
Volume of the Acid used = Initial reading - Final reading = 25.00 - 15.50 = 9.500 mL
Volume of the base used = 8.80 - 5.00 = 3.800 mL
5)
We know that the mole ratio is 1:2 and the implication of this is that the set up to obtain the molarity of the sodium hydroxide solution is Molarity of HCl * 1/2
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An aqueous solution of ________ will produce a basic solution.
NaClO4
Na2SO3
NaNO3
LiBr
NH4I
Answer:
Explanation:
NH4I NH4 is ammonium thus a base. All other bases end with OH except ammonia which is NH3
Mescaline a hallucinogenic amine obtained from the peyote cactus has been synthesized in two steps from 3 4 5 trimethoxybenzyl bromide The first step is nucleophile substitution by sodium cyanide. The second step is a lithium aluminum anhydride reduction. Indicate the reactions and give the structure of mescaline
Mescaline produces a wide range of psychoactive effects when ingested, including altered perception of reality, hallucinations, and euphoria. It is a powerful psychedelic drug that has been used for centuries by Native American tribes in spiritual ceremonies
Mescaline is a hallucinogenic alkaloid that is derived from the Peyote cactus. Mescaline is a complex organic molecule that can be synthesized in the laboratory from 3,4,5-trimethoxybenzyl bromide in two steps.The first step involves nucleophilic substitution using sodium cyanide, and the second step is a reduction using lithium aluminum hydride (LAH).Here's how mescaline can be synthesized from 3,4,5-trimethoxybenzyl bromide:Step 1: Nucleophilic substitution using sodium cyanideThe reaction of 3,4,5-trimethoxybenzyl bromide with sodium cyanide results in the formation of the nitrile derivative. NaCN serves as the nucleophile in this reaction, and it replaces the bromide ion.The mechanism for this reaction involves the following steps: A nucleophilic attack by the cyanide ion on the benzyl bromide. The carbon-bromine bond breaks, and the benzyl cation is formed. A second nucleophilic attack by the cyanide ion occurs on the benzyl cation, resulting in the formation of the nitrile derivative.Here's the reaction equation for this step:Step 2: Reduction using lithium aluminum hydrideThe next step is the reduction of the nitrile derivative using LAH. LAH serves as a strong reducing agent in this reaction and reduces the nitrile derivative to the amine. The mechanism for this reaction involves the following steps: A nucleophilic attack by LAH on the nitrile derivative. This results in the formation of an imine intermediate. The imine intermediate reacts with another LAH molecule, resulting in the formation of the amine.Here's the reaction equation for this step:Mescaline structure: Mescaline is a psychoactive compound that belongs to the phenethylamine class of alkaloids. The structure of mescaline is as follows: The molecule has three methoxy groups attached to the benzene ring, and it has an amine functional group. The molecule is a white crystalline powder that is soluble in water and alcohol.
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I need help calculating the error % in molar mass
Type the correct answer in the box. The density is 1.26grams/ centimeters. How many pounds/foot is this? Use the conversion rates of 454 grams/1 pound and 28,317 centimeters/1 ft.. Express your answer to the correct number of significant figures.
Answer: 78.59 lb/ft
Explanation:
use stoichiometry to solve
1.26g/cm x ( 1pound/ 454 grams) X (28317 Cm/1 ft) = 78.59 pounds/ft
URGENT HELPPP PLEASE
Use the information to answer the following question.
Several groups of Chemistry students are tasked with producing aluminum chloride using solid aluminum as
reactant. The teacher provides the students with two forms of aluminum, powder and solid chunks.
Which type of aluminum should the students plan to use in order to increase the reaction rate?
A Powder, because the greater surface area will allow more collisions between reactants to occur
B Solid chunks, because the lower surface area will allow more collisions between reactants to occur
C Solid chunks, because the greater surface area will allow more collision between reactants to occur
D Powder, because the lower surface area will allow more collisions between reactants to occur
The type of aluminum the students should plan to use in order to increase the reaction rate is powder because the greater surface area will allow more collisions between reactants to occur.
The correct option is A.
How does the surface area of the reactants affect the rate of reaction?The nature of the surface area of the reactants will either decrease or increase the rate of reaction.
An increased surface area of the reactants will increase the rate of a reaction because the greater surface area will allow more collisions between reactants to occur.
A decrease in the surface area of the reactants will decrease the rate of a reaction because the greater surface area will not allow more collisions between reactants to occur.
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1. Show a correct numerical setup for calculating the molarity of the sodium hydroxide solution.
2. Determine both the total volume of HCl(aq) and the total volume of NaOH(aq) used in the titration.
To calculate the molarity of the sodium hydroxide (NaOH) solution, we need to perform a titration with a standardized solution of hydrochloric acid (HCl). Here is the numerical setup for calculating the molarity of the NaOH solution:
Measure the volume of the HCl solution used in the titration. Let's say you used 25.0 mL of 0.100 M HCl.
Calculate the number of moles of HCl used in the titration: moles of HCl = M x V = 0.100 mol/L x 0.0250 L = 0.00250 mol.
Use the balanced chemical equation for the reaction between HCl and NaOH to determine the number of moles of NaOH that reacted with the HCl. The balanced chemical equation is:
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
Since the stoichiometry of the reaction is 1:1 between HCl and NaOH, the number of moles of NaOH that reacted is also 0.00250 mol.
4. Determine the volume of NaOH used in the titration. Let's say you used 30.0 mL of NaOH solution.
Calculate the molarity of the NaOH solution: Molarity of NaOH = moles of NaOH / volume of NaOH solution (in L) = 0.00250 mol / 0.0300 L = 0.0833 mol/L.
To determine the total volume of HCl(aq) and NaOH(aq) used in the titration, simply add together the volumes of HCl and NaOH that were used. In this example, the total volume would be 25.0 mL + 30.0 mL = 55.0 mL.
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Unit: Acids, Bases, and Solutions
"Properties of Acids and Bases" - WS #3
Five properties that make acids different from bases include their pH, conductivity, taste, texture, and reactivity.
The names of the given acids and bases are:
1. Hydrogen fluoride
2. Potassium hydroxide
3. Hydrogen sulfate
4. Calcium hydroxide
5. Barium hydroxide
6. Hydrogen nitroxide
7. Barium hydroxide
8. Hydrogen sulfide
9. Aluminum hydroxide
10. Dihydrogen phosphate
How to differentiate acids from basesAcids can be differentiated from bases by their taste, pH, texture, reactivity, etc. Acids typically have a sour taste while bases have a bitter taste. Acids also have a pH less than 7while bases have a pH greater than 7.
Acids and bases also differ in their texture. Acids have a sticky texture while bases have a slippery texture. The conductivity of acids is also greater than those of bases.
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What is the mass of a sample of NH3 containing 6.3 × 1024 molecules of NH3?
Answer:
i dont know sorry, hope you get the answer•
Please help solve these chemistry questions!!!
Practice with percent composition.
1. What is the percent composition of Fe if 111.7 g of Fe is recovered from a 159.7 g sample of Fe2O3?
2. What is the percent composition of O if 12 g of O is recovered from a 38 g sample of Cr2O3?
3. Calculate the percent composition of KCl.
4. Calculate the percent composition of N2O5.
Practice with empirical formulas
5. What is the empirical formula for a compound that contains 0.0260 mol C, 0.0325 mol H, and 0.0065 mol O.
Practice with Molecular Formulas
6. Determine the molecular formula for a compound that has an empirical formula of NO2 and a molar mass of 138.015 g/mol.
7. Nicotine is 74.1% C, 8.6% H, and 17.3% N by mass. It’s molar mass is about 160 g/mol.
a. What is it’s empirical formula?
b. What is it’s molecular formula?
Please answer part C (the answers for other parts are in the screenshots).
Part C: What is the activation energy of the reaction? Express your answer numerically in kilojoules per mole
The formula for the activation energy was used to obtain;
a. The result is -2.11 * 10^-4 K
b. The result is -3.29
What is the activation energy?The bare minimum of energy required to start a chemical reaction is referred to as activation energy. For a reaction to move from the reactants to the products, the energy barrier must be broken.
To break existing bonds and generate new ones, reactant molecules must collide with enough force and in the proper direction during a chemical reaction. The energy needed to dissolve these bonds and start the atoms moving around to generate the products is known as the activation energy.
We know that we can use the formula;
1/T2 - 1/T1
= 1/318 - 1/298
= -2.11 * 10^-4 K
Again;
ln(k1/k2) = ln(0.1/2.70)
= -3.29
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Question 1
Recall all the models you described in task 1. (Rutherford, Dalton,and Bohr) Think about the results each model would predict for Thomson's experiment. Which atomic models does Thomson's experimental evidence support? Exp why these models are compatible with the experimental results.
Thomson's experimental evidence supports Rutherford's atomic model, as it aligns with the observed behavior of the cathode rays in the cathode ray tube experiment
Thomson's experiment, known as the cathode ray tube experiment, involved passing an electric current through a partially evacuated tube and observing the behavior of the cathode rays. Thomson discovered that the cathode rays were negatively charged particles, which later came to be known as electrons. Based on Thomson's experimental evidence, it is compatible with Rutherford's model, which proposed a dense positively charged nucleus and negatively charged electrons. Thomson's experiment indicated the presence of negatively charged particles (electrons) and their deflection towards the positively charged plate, supporting the idea of a small, dense, positively charged nucleus within the atom. In summary, Thomson's experimental evidence supports Rutherford's atomic model, as it aligns with the observed behavior of the cathode rays in the cathode ray tube experiment. The experiment provided strong evidence for the existence of negatively charged electrons within atoms and the presence of a small, dense, positively charged nucleus.
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Which scientist wrote the Book of Optics?
O A. Warren Washington
O B. In al-Haytham
O C. Christian Doppler
O D. Galileo Galilei
The scientist who wrote the Book of Optics is In al-Haytham.
option B.
Which scientist wrote the Book of Optics?The Book of Optics presented experimentally founded arguments against the widely held extramission theory of vision (as held by Euclid in his Optica), and proposed the modern intromission theory, the now accepted model that vision takes place by light entering the eye.
The Book of Optics is a seven-volume treatise on optics and other fields of study composed by the medieval Arab scholar Ibn al-Haytham, known in the West as Alhazen or Alhacen.
Thus, the scientist who wrote the Book of Optics is In al-Haytham.
Other options such as Warren Washington, Christian Doppler and Galileo Galilei are not correct.
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Which sample uses the substance(s) that Jacob and Natalie
should use to make a cold pack that will do the BEST job of
keeping food cool
The sample that uses the substance that Jacob and Natalie should use to make a cold pack that will do the best job of keeping food cool is sample 2, because it absorbs the most energy (option B).
What is endothermic process?Endothermic refers to a chemical reaction that absorbs heat energy from its surroundings. This ensures that the temperature of the surroundings is cool or has a lower temperature.
According to this question, Jacob and Natalie are asked by their science teacher to design a warming or cooling device. They make use of certain substances, however, sample 2 has the lowest final temperature of -4°C.
This shows that sample 2 absorbs the most energy, hence, would be the best for keeping the food cool.
The incomplete question is as follows:
Jacob and Natalie are asked by their science teacher to design a warming or cooling device. They decide to design a cold pack that can be used to help keep food cool. Jacob and Natalie read about different substances that can be used inside cold packs and learn that most cold packs use endothermic reactions to cool objects.
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What is an activated complex?
Answer:
What is meant by activated complex?
The state of the particles that is in between the reactants and products is called the activated complex. An activated complex is an unstable arrangement of atoms that exists momentarily at the peak of the activation energy barrier.
source:Gogle
A student placed 6.0 grams of baking soda into a small balloon. The mass of the
balloon and soda was measured at 7.0 grams. Next, the student poured a measure of
vinegar into a Florence flask that had an empty mass of 100 grams. After the balloon
was stretched across the top of the flask, the student dumped the soda into the vinegar.
A gas was formed by a chemical reaction that filled the balloon. After the reaction
stopped, the student placed the flask with the filled balloon on a balance scale and it
measured 125 grams.
What was the mass of the vinegar the student put in the flask at the start?
The mass of the vinegar the student put in the flask at first is 18 grams.
How do we solve for the mass of the vinegar?To find the mass of the vinegar, you have to consider the law of conservation of mass.
Ths law says that the total mass of the reactants before a chemical reaction is equal to the total mass of the products after the reaction.
Therefore
Mass of vinegar = Total mass after reaction - (mass of flask + mass of balloon with baking soda)
= 125 grams - (100 grams + 7 grams)
= 18 grams
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What Is the ph of a solution where [h30+]3.5*10-3=
The pH of the solution with a [H₃O⁺] concentration of 3.5 * 10^(-3) mol/L is approximately 2.456.
To determine the pH of a solution based on the concentration of H₃O⁺, you can use the equation:
pH = -log[H₃O⁺]
Given that [H₃O⁺] = 3.5 * 10^(-3) mol/L, we can substitute this value into the equation:
pH = -log(3.5 * 10^(-3))
To evaluate this using a calculator or math software:
pH ≈ -log(3.5 * 10^(-3)) ≈ -(-2.456) ≈ 2.456
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The unique properties of water are due to the water's
Question 32 options:
A. density
B. ionic bonds
C. polar nature
D. high heat capacity
Answer:
C. polar nature
Explanation:
The polarity of water and its ability to hydrogen bonding contributes to it's unique properties
Step 4: Compute the pH of the Solutions
The pH scale determines how acidic or basic water is. The range is 0 to 14, with 7 representing neutrality.
Thus, Acidity is indicated by pH values below 7, whereas baseness is shown by pH values above 7. In reality, pH is a measurement of the proportion of free hydrogen and hydroxyl ions in water.
While water with more free hydroxyl ions is basic, water with more free hydrogen ions is acidic. Since chemicals in the water can change pH, pH is a crucial sign that the chemical composition of the water is changing. "Logarithmic units" are used to report pH.
Each number corresponds to a 10-fold difference in the water's acidity or basicity. Ten times more acidic than water is water is water with a pH of five.
The pH scale determines how basic or acidic a substance is. We consume a variety of drinks with varying pH levels during our daily lives. A neutral material is water. The acidity of soda and coffee varies.
Thus, The pH scale determines how acidic or basic water is. The range is 0 to 14, with 7 representing neutrality.
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5. An alcoholic drink containing 216.0 g of H2O and 9.2 g of ethanol (C2H5OH) is bottled by adding CO2. If the mole fraction of water is 0.9 what approximate mass of CO2 is dissolved in it?
The approximate mass of CO2 dissolved in the alcoholic drink is 832.5 grams.
To calculate the approximate mass of CO2 dissolved in the alcoholic drink, we need to consider the mole fraction of water and the composition of the solution.First, let's determine the number of moles of water and ethanol in the solution:
Molar mass of H2O = 18.02 g/mol
Number of moles of H2O = mass of H2O / molar mass of H2O = 216.0 g / 18.02 g/mol = 11.994 mol
Molar mass of C2H5OH = 46.07 g/mol
Number of moles of C2H5OH = mass of C2H5OH / molar mass of C2H5OH = 9.2 g / 46.07 g/mol = 0.1998 mol
Next, we can calculate the mole fraction of ethanol:
Mole fraction of ethanol = (moles of C2H5OH) / (moles of H2O + moles of C2H5OH) = 0.1998 mol / (11.994 mol + 0.1998 mol) = 0.0164
Since the mole fraction of water is given as 0.9, we can calculate the mole fraction of CO2:
Mole fraction of CO2 = 1 - (mole fraction of water + mole fraction of ethanol) = 1 - (0.9 + 0.0164) = 0.0836
Now, we need to determine the mass of CO2 dissolved in the solution. Assuming ideal behavior, we can use Raoult's law to calculate the approximate mass of CO2:
Mass of CO2 = (mole fraction of CO2) * (molar mass of CO2) * (total mass of the solution)
= 0.0836 * 44.01 g/mol * (216.0 g + 9.2 g)
= 0.0836 * 44.01 g/mol * 225.2 g
≈ 832.5 g
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