Answer:
yes, they were
Explanation:
The history of the metric system began in the Age of Enlightenment with notions of length and weighttaken from natural ones, and decimal multiples and fractions of them. The system became the standard of France and Europe in half a century. Other dimensions with unity ratios[Note 1] were added, and it went on to be adopted by the world.
Select the words that correctly complete the sentences. A class uses 10 students to model a lithium atom. Each student represents a particle in the atom. Three students wear signs with a “+” sign, representing (electrons / neutrons / protons). The four students with “0” signs represent (neutrons / protons / electrons ). Each of the remaining students wear a “–” sign, representing (protons / electrons / neutrons)
Answer:
Explanation:
Protons.
Electrons.
Neutrons.
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Determine the mass in grams of 2.98 × 10²¹ atoms of arsenc. Determine the mass in grams of 2.98 × 10²¹ atoms of arsenc.
Answer:
37.1 g of Arsenic
Explanation:
2.98 x 10^21 atoms of Arsenic x 74.92g/6.02 x 10^23
= 223.26 x 10^21/6.02 x 10^23
= 2.2326 x 10^23/6.02 x 10^23
= 37.1 g of Arsenic
Determine the equilibrium expression for the following reaction:
2NaHCO3(s)⇋Na2CO3(s)+H2O(g)+CO2(g)
Answer:
K = [Na2CO3] [H2O] [CO2] / [NaHCO3]²
Explanation:
2NaHCO3(s)⇋Na2CO3 (s) + H2O(g) + CO2(g)
To write an expression for equilibrium constant, K, for the above reaction, it is important that we have an idea of what equilibrium constant is all about and how we can determine it.
Equilibrium constant for a reaction is simply defined as the ratio of the concentration of the product raised to their coefficient to the concentration of the reactant raised to their coefficient.
Thus the expression for the equilibrium constant for the above equation can be written as follow:
K = [Na2CO3] [H2O] [CO2] / [NaHCO3]²
What is another name for Group 6A? O A. Group A6 O B. Group 6B O C. Group 16 D. Group 6
Answer: group 16
Explanation: apex
What is the use of density in the calculation of percentage by mass?
Answer:
First, the direct method requires recording the total mass of solution, and then evaporating off the solvent. The solid left behind is the solute, which is then weighed and used to calculate mass percent. Density can also be used to determine the mass percent of an unknown concentration.
in my opinion:)
Aqueous hydrochloric acid HCl will react with solid sodium hydroxide NaOH to produce aqueous sodium chloride NaCl and liquid water H2O. Suppose 9.84 g of hydrochloric acid is mixed with 3.1 g of sodium hydroxide. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 2 significant digits.
Answer:
1.4 g H₂O
Explanation:
In a reaction, the reactants are usually not present in exact stoichiometric amounts, that is, in the proportions indicated by the balanced equation. Frequently a large excess of one reactant is supplied to ensure that the more expensive reactant is completely converted to the desired product. Consequently, some reactant will be left over at the end of the reaction. The reactant used up first in a reaction is called the limiting reagent, because the maximum amount of product formed depends on how much of this reactant was originally present. When this reactant is used up, no more product can be formed.
How many sig figs are in 340.0 mL
Answer:
4
Explanation:
there is a decimal place present. so you would take away any zeros before the number.
Answer:
4 i think
Explanation:
Naturally occurring boron has an atomic mass of 10.810 amu consists of two isotopes. One of those isotopes is 10B with an isotopic mass of 10.0129 amu and an abundance of 19.9%. What is the isotopic mass of the other isotope?
Answer:
boron has an atomic mass of 10.810 amu consists of two isotopes.
Answer:
boron has an atomic mass of 10.810 amu consists of two isotopes.
Explanation:
What ions are present in an aqueous solution of NiCl2?
Answer:
Ni²⁺ and Cl⁻ ions
Explanation:
NiCl₂ is an ionic compound which is composed by 2 chloride ions (Cl⁻) and 1 nickel (II) ion (Ni²⁺). It dissociates in water as follows:
NiCl₂ ⇒ Ni²⁺ + 2 Cl⁻
Therefore, in an aqueous solution of NiCl₂ will be present Ni²⁺ ions and Cl⁻ ions.
Which statement is incorrect concerning the formation of ionic compounds?
a Halogens tend to form anions with a charge of -1.
b. Alkali metals tend to form cations with a charge of +1.
c. Metals tend to form cations, while nonmetals tend to form anions.
d. Transition metals tend to form cations with a charge of +3.
e. Noble gases tend not to form ionic compounds.
Answer:
d. Transition metals tend to form cations with a charge of +3.
Explanation:
Which statement is incorrect concerning the formation of ionic compounds?
a. Halogens tend to form anions with a charge of -1. TRUE. Halogens have 7 electrons in their valence shell, so they tend to gain 1 electron to fill their octet.
b. Alkali metals tend to form cations with a charge of +1. TRUE. Alkali metals have 1 electron in their valence shell, so they tend to lose 1 electron to fill their previous octet.
c. Metals tend to form cations, while nonmetals tend to form anions. TRUE. Metals have low electronegativity while nonmetals have high electronegativity.
d. Transition metals tend to form cations with a charge of +3. FALSE. Transition metals form cation with numerous charges.
e. Noble gases tend not to form ionic compounds. TRUE. Noble gases are very stable because their octet is full.
The element X has three naturally occurring isotopes. The isotopic masses (amu) and % abundances of the isotopes are given in the table below. Calculate the average atomic mass of the element in amu. PLEASE HELP ASAP
Answer:
162.349
Explanation:
(.3060 * 159.37) + (.1579 * 162.79) + (.5361 * 163.92) = 162.349
The sense of hotness or coldness by touching always does not work well.why?
Answer:
because if the hotness should more it will give it increase the temperature of earn water but it is not so because you have taken out hands from your and cold water So it is reliable
Ms. Sharkey wanted to see which tennis shoes made her run the fastest. She bought
a pair of Brooks, Adidas, and Nike and ran a mile in each to see which one gave her
the shortest time and recorded the data. What is her next step?
Answer:
to compare the data she has got?
Materials
80 mL Carbonated Water
80 mL Acetic Acid
(2) Chalk Pieces (CaCO3)
Permanent Marker
*80 mL Tap Water
*Timer (watch, cell phone, internet, etc.)
Note: You must provide the materials listed in *red.
Labware
(3) 250 mL Beakers
Digital Scale
EXERCISE 1: SPELEOLOGY (UNDERSTANDING CAVE FORMATION)
In this exercise, you will observe what happens to chalk in different solutions and compare your observations to what occurs in nature.
1. Do the results of the exercise support your hypothesis? Explain your reasoning.
2. Compare and contrast the reaction of the chalk pieces in each solution.
3. Is this exercise an analog for physical or chemical weathering? Explain your reasoning.
4. Using your observations of the chalk in different solutions, explain how a limestone cave forms.
Answer:
Limestone caves are formed when acid rain occurs.
Explanation:
When chalk pieces which is made of calcium carbonate react with acetic acid, it produces carbon dioxide, calcium acetate, and water. When calcium carbonate react with Carbonated Water produces calcium bicarbonate. Limestone cave forms when the dissolution of limestone occur when rainwater which is acidic due to the addition of carbondioxide in the air react with limestone. This dissolution removes the lime from the rock and caves are formed.
The chalk has been made up of calcium carbonate. The reaction of calcium carbonate with different solutions results in the formation of varying products.
The reaction of chalk with acetic acid results in the formation of Calcium acetate, with the production of carbon dioxide and water.
The reaction of chalk with carbonated water results in the formation of calcium bicarbonate.
The limestone caves has been formed by the dissociation of limestone with reaction of acid, forming carbon dioxide.
The formation has takes place in the acidic solution, and carbon-dioxide thus the resultant can be due to the acid rain.
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Explain why CaCl2 is likely to have properties similar to those of CaBr2
Answer:
Because both compounds (CaCl2 and CaBr2) contain elements (bromine and chlorine) from the same group (group 7)
Explanation:
Elements are organized into groups on the periodic table based on the number of valence electrons contained in their outermost shell. These elements in the same group i.e. same number of valence electrons, will behave in a similar manner chemically.
CaCl2 and CaBr2 are two compounds that contains elements (Chlorine and Bromine) from the same group, which is group 7. Elements in group 7 are called HALOGENS and have 7 valence electrons in their outermost shell.
Bromine (Br) and Chorine (Cl) are responsible for the similarity in the properties of CaCl2 and CaBr2 because the Chlorine and Bromine contained in them will cause them to react similarly and behave similarly in the presence of other compounds.
what is the difference between ecosystem services natural resources
Answer: Ecosystem services are the flows of benefits which people gain from natural ecosystems, and natural capital is the stock of natural ecosystems from which these benefits flow. So, a forest is a component of natural capital, while climate regulation or timber might be the ecosystem service it provides.
Over the course of many years, a rural farm town becomes more urban. Which of the following will most likely happen in the town as a result of this urbanization?
Answer:
Explanation:
Rivers may be contaminated by sewage.
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What are the characteristics for natural resources ?
Answer:
The characteristcs of natural resources are commercial and industrial use.
It includes soil, salt, oil, natural gas, coal, iron.
During which change of state do atoms lose energy?
A. Sublimation
B. Freezing
C. Boiling
D. Melting
If you answer my question Thank You, If I don't thank you in time!
What substance is neither an acid nor a base? How does it stay neutral? HURRY PLS
Answer:
21. Most metals are brittle.
22. increases from top to bottom within the group
23. Neon is the most stable element because its highest occupied energy level is filled.
24. transfer of electrons
25. electrons are not shared equally between atoms
26. BeCl2
27. double-replacement and decomposition
28. exothermic
29. The reaction rate decreases.
30. The salt dissolved most quickly in the warm water.
31. saturated
32. feels slippery
33. hydroxide ions in solution
34. stay about the same
35-40. I do not know.
41. a bee hovering around a bee hive
42. the number of valence electrons in atoms of the element
Explanation:
21. Metals are ductile and malleable (conveniently also characteristics for chewing gum). They are stretchy and squishy. Brittle is the opposite of stretchy and squishy, and is a characteristic of non-metals.
22. On the periodic table, elements higher up are safer to use in labs. They are safer because they are less likely to react with other substances. Therefore the tendency to react with other substances increases from top to bottom within the group.
23. "Noble gases stable" (periodic table song by ASAP Science). Neon is a noble gas, therefore it is stable. When elements have only one electron to gain or lose, they are very reactive or least stable.
24. The formation of an ionic bond (metal + non-metal) is caused by the giving and receiving of electrons. Neutrons and protons do not transfer. Electrons are shared in covalent/molecular bonds (between non-metals).
25. A polar covalent bond occurs between non-metals, therefore they share electrons (ionic bonds transfer electrons). Non-metals become anions (whereas metals become cations). Polar bonds have unequal sharing and nonpolar bonds have equal sharing.
26. A one-to-two ratio of beryllium ions to chloride ions means for every Be, there are two Cl. The number of atoms is represented by the ratio, and the numbers of atoms are written as subscripts after the element symbol.
27. MgCO2 reacting with HNO3 to form magnesium nitrate and carbonic acid is a double-replacement reaction. The elements in the beginning substances "switch partners" to form the products.
Carbonic acid then breaks down into water and carbon dioxide is decomposition. This occurs when the elements that make up a compound are split up.
28. In 2Cu + O2 => 2CuO + 315 kJ , the energy is on the right side. The right side is the products, or the stuff that was made. kJ is a unit to measure energy, therefore energy was made. Exothermic is the term that means energy was released.
29. Since oxygen is needed for a fire to burn, decreasing the oxygen slows the reaction rate (the reaction is burning, formally known as combustion).
30. Two things help substances dissolve: heat and stirring. Warm water is hotter than room-temperature water and ice water. This makes the salt dissolve faster.
31. A solution that contains more solute than it would normally hold is saturated. Saturated means there is a more than concentrated amount of solute in the solution. Concentrated is when there is a maximum amount of solute that will dissolve.
32. Acids do not feel slippery -- that is a characteristic of a base. To remember, bases are generally soaps and soaps are slippery. Acids taste sour and bases taste bitter. Both acids and bases change the color of an indicator .
33. A base produces hydroxide ions, represented by OH. The OH is usually at the end of the chemical formula. Acids produce hydrogen ions, generally written at the front of the chemical formula.
34. Adding a little bit of acid to a buffer will cause the pH of the solution to stay about the same, probably increase a little. Buffer solutions are meant to make the pH "buffer". To remember, DVDs used to buffer. It's the same thing as "lag" for phones.
35-40: I'm sorry, I have no answer.
41. Electrons orbit like the plants revolve around the sun. Electrons revolve around a nucleus. A bee hovering around a bee hive is probably flying around it in circles.
42. The tendency of an element to react is closely related to the number of valence electrons in atoms of the element. If the valency is 8, the electron shell is full. The element is stable, opposite to reactive -- this applies to all noble gases (group 8A on the periodic table). If the valency is 1 or 7, the element is very close to being stable but not, the "desire" is so great and makes the element very reactive.
Which ONE of the following compounds is least soluble in water?
A) CH3CH2CH2NH2
B) CH3CH2CH2F
C) CH3CH(OH)CH3
D) CH3CH2COOH E) CH3CH2NHCH3
The one compound among the given options that is least soluble in water is;
Option B; CH₃CH₂CH₂F
We know in chemistry that hydrogen bonding affects solubility in that the presence of hydrogen bonding between the molecules of a substance show us that such molecules are polar. This therefore means that the molecules will be soluble in a polar solvent such as water.
Looking at the options, all of them form hydrogen bonds except for Option B which has Fluorine (F) alone not directly bonded to hydrogen. Instead the fluorine will be bonded to a carbon atom which means it is not going to be easily soluble in water.
In conclusion, the one compound that would be the least soluble in water is CH3CH2CH2F.
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The compound that is the least soluble in water is CH₃CH₂COOH, which is also known as ethanoic acid or acetic acid. Therefore, option D is correct.
Ethanoic acid is a weak acid that partially ionizes in water, releasing hydrogen ions (H+) and acetate ions. However, it does not fully dissociate into ions and remains mostly in the molecular form.
1-propanamine can form hydrogen bonds with water through the amine functional group, enhancing its solubility.
1-fluoropropane has a polar C-F bond and can also experience dipole-dipole interactions with water, making it more soluble.
2-propanol, or isopropyl alcohol, is capable of hydrogen bonding with water due to the presence of the hydroxyl group, increasing its solubility.
Dimethylamine can form hydrogen bonds with water through the amine functional group, resulting in higher solubility.
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find the R when p=6000,T=3 yrs 6 month ,I=1155
R= 1155×100/6000×3/12
R= 1155×2/3
R=770The element X has three naturally occurring isotopes. The isotopic masses (amu) and % abundances of the isotopes are given in the table below. Calculate the average atomic mass of the element in amu. PLEASE HELP ASAP THANK YOU SO MUCH
Answer:
162.35 amu
Explanation:
Let A represent isotope X-159
Let B represent isotope X-163
Let C represent isotope X-164
The following data were obtained from the question:
Isotope >>> Abundance >>> Mass no
A >>>>>>>> 30.60 >>>>>>>> 159.37
B >>>>>>>> 15.79 >>>>>>>>> 162.79
C >>>>>>>> 53.61 >>>>>>>>> 163.92
Average Atomic mass =.?
The average atomic mass of element X can be obtained as follow:
Average atomic mass = [(mass of A × A%)/100] + [(mass of B × B%)/100] + [(mass of C × C%)/100]
= [(159.37 × 30.60)/100] + [(162.79 × 15.79)/100] + [(163.92 × 53.61)/100]
= 48.77 + 25.70 + 87.88
= 162.35 amu
Therefore, the average atomic mass of element X is 162.35 amu
the number of electrons in n=1 and n=2 shells of aluminum are
Answer:
n=1 holds two electrons and n=2 holds eight electrons.
Explanation:
Hello
In this case, since the atomic number of aluminum is 13, its electron configuration is:
[tex]Al^{13}: 1s^2,2s^2,2p^6,3s^2,3p^1[/tex]
In such a way, we can see that the level n=1 is filled with two electrons since the subshell s is able to hold two electrons and the level n=2 is also filled but with eight electrons as s holds two whereas p holds 6. Moreover, n=3 is holding three electrons.
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Which action changes the identity of substance referenced
Answer:
When iron turns to rust, the chemical identity of the iron changes. When you break ice, the ice is still ice
What are the best practices for safely handling waste in the lab? Select one or more: Check labels or instructions before any disposal. Always wear appropriate Personal Protective Equipment. Place any paper towels from the clean-up in the trash. Remove gloves for better manipulation of the waste containers
Answer:
Consult labels or instructions before disposing of it. Always wear the proper personal protective equipment. Put all cleaning paper towels in the trash
Explanation:
Gloves should never be removed when disposing of waste, since these can contain infected fluids or even cultivated microorganisms that are pathogens for our lives and can enter through a lesion of the continuity solution of the epithelium in our hands.
In other words, if there is a wound, and it is contaminated with waste by not wearing gloves, the risk of contracting diseases is much greater.
Read this description of the life cycle of a mushroom. 1. A mushroom begins to grow underground as a single-celled "spore.” 2. The spore grows into multicellular structures called "hyphae.” 3. The hyphae absorb nutrition and detect when conditions are right to sprout a mushroom above ground. 4. The sprouted mushroom then forms new spores that can enter the ground and begin the life cycle again. Which sentence about this life cycle shows that mushrooms need energy and respond to stimuli? A: A mushroom begins to grow underground as a single-celled “spore.” B: The spore grows into multicellular structures called “hyphae.” C: The hyphae absorb nutrition and detect when conditions are right to sprout a mushroom above ground. D: The sprouted mushroom then forms new spores that can enter the ground and begin the life cycle again
Answer:
Explanation:
I would sayy....C The hyphae absorb nutrition and detect when conditions are right to sprout a mushroom above ground.
Um I hope I helped bro :P
(-W-) but where's da cOokIeS??..........................Lol jkkk
Answer:
D THE SPROUTEEDMUSHROOM
Explanation:
1. You bought a loaf of bread and on the way home, the loaf of bread was crushed. Is the density of the crushed bread the same density as the uncrushed bread? If the density of the crushed bread is different from the density of the uncrushed bread, tell which bread has the higher density. Explain how you know.
Answer:
No. It is more dense than the uncrushed bread.
Explanation:
The mass is the same, however the volume has been decreased on the crushed side, forcing more matter into one space, which increases the density.
The loaf of bread was crushed then the density of crushed bread and uncrushed bread is same.
What is density?Density is defined as a measurement of how tightly the material is packed together.
It can also be defined as mass of a unit volume of a material substance.
Density can be expressed as
Density = mass / volume
The density depends on mass and volume and mass and volume of crushed and uncrushed bread is same only surface area changes with structural deformation.
Thus, the loaf of bread was crushed then the density of crushed bread and uncrushed bread is same.
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Which of the following is a buffer system?
A. NaCl and NaNO3
B. H2CO3 and KHCO3
C. HCl and NaOH
D. H2O and HCl
E. NaCl and NaOH
Answer:
B. H2CO3 and KHCO3
Explanation:
The buffer system is a system in which the solution deny for change in the ph level i.e. at the time when the acid is added to it. It can be made either in a weak acid and salt or can be a weak base and its salt. Now when the acid is added to a buffer so the ratio is not impacted due to which it does not change sufficient for pH level
As per the given options, the third one is correct as the H2CO3 denotes a weak acid and the KHCO3 represents the salt. And these two solution does not create any change in the level of pH
Therefore the option B is correct
substance A is a nonpolar liquid and has only dispersion forces among its constituent particles. Substance B is also a nonpolar liquid and has about the same magnitude of dispersion forces among its constituent particles as substance A. When substance A and substance B are combined, they spontaneously mix. Why
Explanation:
The substance A and B will mix into one solution as it is a solvent interactions which is greater than or equal to the solute- solute and the solvent-solvent interactions. Thus when such interactions occurs, it is greater or equal to the some of the other two possible interactions. And here both have the same kind of interaction, and same magnitude, so they will makes to form a solution and mixes properly and spontaneously.