Why is it important for the buret to be clean before using? How do you clean a buret
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Related Questions
Which is more reactive copper or calcium? Why?
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this is because calcium will lose will lose more electrons and is a group 2 metal, copper is a transition metal which is a lower position and more stable than calcium.
Answer:
Calicum
Explanation:
This is true because calcium loses more electrons and is a group 2 metal
Is Ca + O --> CaO a balanced chemical equation? Is it obeying the law of conservation of matter? Question 5 options: Yes it is balanced. It has the same number of Ca and O on both the reactant side and the product side. No it is not balanced. It has more Ca on the product side than the reactant side. No it is not balanced it has more O on the reactant side than the product side.
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Answer is: Yes it is balanced. It has the same number of Ca and O on both the reactant side and the product side.
According to principle of mass conservation, number of atoms must be equal on both side of chemical reaction.
There is one calcium atom atom and one oxygen atom on both side of reaction, so chemical reaction is balanced.
Which of these is an example of a physical change -baking a cake -toasting bread -grinding pepper -lighting up a grill
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An example of a physical change is grinding pepper. Physical change is when there is no change in the chemical composition of the substance.
What are physical changes?Physical changes are those changes in which the physical composition of the substance changes but the chemical composition of the substance or compound remains the same.
Examples are ice melting into water. It is a physical change. Like here, the baking cake is a chemical change in which the substance changes into other substances.
And grill lighting is a chemical change. Toasting bread is a chemical change in which the bread substance is burning. Pepper grinding is a process of physical change because it's just crushing the pepper.
Therefore, an example of physical change is grinding pepper.
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Want answers and how to do this, please.
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Density is an intensive property in that increasing the amount of a substance _________ increase its density.
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Density is the mass-to-volume ratio of a substance and is an intensive property, meaning it does not change when the amount of substance is increased.
Explanation:The density (d) of a substance is an intensive property that is defined as the ratio of its mass (m) to its volume (V). Density is an important characteristic of substances and plays a critical role in phenomena such as whether an object will sink or float in a fluid.
Increasing the amount of a substance does not increase its density because density is proportional to the mass and volume of a substance. Since both mass and volume are extensive properties (meaning they depend on the amount of the substance), when they are increased proportionally, their ratio, which is density, remains constant. Thus, the density of a substance is independent of the amount of substance present at a given temperature and pressure.
Final answer:
The density of a substance, a ratio of mass to volume, remains constant irrespective of the amount, making it an intensive property.
Explanation:
Density is an intensive property of a substance, which means it is characteristic of the substance itself and does not depend on the amount of the substance present. The density (d) of a substance is defined as the mass (m) of the substance divided by its volume (V).
Even though mass and volume are extensive properties (they depend on the amount of substance), the reason their ratio (density) is an intensive property is that it remains constant for a substance regardless of how much of it you have. This ratio measures how much mass exists in a given unit volume and, at a given temperature and pressure, this value does not change, no matter the sample size.
This distinction is important in physics and engineering, as density plays a critical role in determining whether an object will sink or float in a fluid, among other applications.
Determine the electronegativity difference between the probable bond type and the more electronegative atom with respect to bonds formed between the pairs of atoms Se and S
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Final answer:
The electronegativity difference between selenium (Se) and sulfur (S) is 0.03, indicating a nonpolar covalent bond. Sulfur (S) is slightly more electronegative than selenium (Se).
Explanation:
To determine the electronegativity difference and predict the bond type between selenium (Se) and sulfur (S), we need to look at their individual electronegativities. Typically, Se has an electronegativity of about 2.55 and S has an electronegativity value of about 2.58. To find the electronegativity difference (AEN) for a bond between Se and S, we subtract these values:
[tex]AEN = X_{S} - X_{Se}[/tex]
= 2.58 - 2.55 = 0.03
Since this difference is very small, the Se-S bond would be classified as nonpolar covalent. The more electronegative atom in this pair is sulfur (S), but because the difference is so minor, there would be little to no polarity in the bond, and both atoms would share the bonding electrons approximately equally.
Final answer:
The electronegativity difference between Se and S is 0.03, indicating a nonpolar covalent bond with Sulfur being slightly more electronegative.
Explanation:
The question asks to determine the electronegativity difference and probable bond type, focusing on a bond between Se and S atoms. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. To estimate the character of the bond as ionic or covalent, we can calculate the difference in electronegativity between Se and S. The electronegativity of Se (Selenium) is about 2.55, and the electronegativity of S (Sulfur) is about 2.58. The difference is 2.58 - 2.55 = 0.03.
This small difference indicates that the bond between Se and S would be nonpolar covalent as the difference in electronegativity is very small. Additionally, since Sulfur is slightly more electronegative than Selenium, it would be the more electronegative atom in this bond. For example, a C-H bond with an electronegativity difference of 0.4 is considered nonpolar covalent, showing that the Se-S bond, with an even smaller difference, is also nonpolar covalent.
Which statement contrasts the two types of mixtures? A. A heterogeneous mixture has a uniform composition, whereas a homogeneous mixture has visually distinguishable parts. B. A heterogeneous mixture has visually identifiable parts, whereas a homogeneous mixture has a uniform composition. C. A solution is composed of a fixed ratio of elements forming a compound, and a heterogeneous mixture has a uniform composition. D. A solution contains a solute and a solvent, whereas a heterogeneous mixture contains a mixture of solvents.
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How reactive is an atom of Sodium(Na) and why?
Question 1 options:
Sodium (Na) is very reactive because it does not have a full valence shell.
Sodium (Na) is very reactive because it does not have enough protons in the nucleus.
Sodium (Na) is not very reactive because it does not have a full valence shell.
Sodium (Na) is not very reactive because it can only bond with Chlorine (Cl) to become salt.
PLz plz plz plz help
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Sodium has an atomic number of 11 and it has only one electron in its outermost shell. For an atom to be stable, it must have eight electrons in its outermost shell. Thus, the reactivity of sodium is due to the fact that it does not have a full valence shell; because of this, it will be very willing to react with suitable elements in order to become stable.
balance the combustion eqation; __C5H + __O2 ---> __CO2+__H2O
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C5H is wrong. You missed the subscript of H.
I will do it for you assuming some subscript to show you the procedure, but you have to use the right equation to get the right balanced equation.
Assuming the tha combustion equation is C5H12 + O2 ---> CO2 + H2O
First you need to balance C, so you put a 5 before CO2 and get
C5H12 + O2 ---> 5CO2 + H2O
Now you count the hydrogens: 12 on the left and 2 on the right. So put a 6 before H2O and get:
C5H12 + O2 ---> 5CO2 + 6H2O
Now count the oxygens: 2 on the left and 16 on the right, so put an 8 on before O2:
=> C5H12 + 8O2 ---> 5CO2 + 6H2O.
You can verify that the equation is balanced
Which scenario suggests that the results of an experiment are reliable?
A. The hypothesis is supported by the results.
B. Repeating the experiment gives the same results.
C. The results are posted on many websites.
D. New questions come up because of the results.
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Hope this helps.
The explosions that take place during a fireworks show are an example of which of the following?Image of fireworks exploding in air
Chemical change
Chemical property
Physical change
Physical property
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:)
hope this helps
Answer:
Chemical change
Explanation:
A chemical change is a change that cannot be reversed. It results in the formation of a new product. For example, the combustion of wood gives carbon dioxide and water and sometimes suit. In other words, in a chemical change, the products are always different from the reactants. The following equation generally governs a chemical change:
[tex]Reactants = Products (solid, liquid, or gas)[/tex]
true or false there are more electrons than protons and negatively charged atom
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a mineral that breaks into irregular pieces is said to show which of the following?
a. cleavage
b. fracture
c. luster
d. hardness
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A)cleavage I actually have that question right now on a test
A mineral that breaks into irregular pieces is said to show cleavage. Therefore, option A is correct.
What is mineral ?A mineral or mineral species is, generally speaking, a solid chemical compound that naturally occurs in pure form and has a very well-defined chemical composition as well as a particular crystal structure.
The following criteria have been developed by the International Mineralogical Association for a substance to be classified as a separate mineral: It must be a substance that is generated naturally, either on Earth or on another extraterrestrial body, through geological processes.
Three key functions of minerals include the development of healthy bones and teeth. managing the internal and external bodily fluids of cells. converting food you consume into energy.
Thus, option A is correct.
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There are more protons than electrons in a negatively charged atom.true or false. it is false, pretty sure
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Protons are positive.
Electrons are negative.
There are more protons that electrons in a positively charged atom.
There are more electrons than protons in a negatively charged atom.
Therefore, it is a false statement.
Hope This Helps You!
Good Luck :)
- Hannah ❤
Answer: false
Explanation:
I got it right
A certain shade of blue has a frequency of 7.07 × 1014 Hz. What is the energy of exactly one photon of this light?
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Answer:
[tex]E=4.68\times 10^{-19}\ J[/tex]
Explanation:
It is given that,
Frequency of shade of blue, [tex]f=7.07\times 10^{14}\ Hz[/tex]
Let E is the energy of exactly one photon of this light. The relationship between the energy and the frequency is given by :
[tex]E=h\times f[/tex]
h is the Planck's constant
[tex]E=6.63\times 10^{-34}\times 7.07\times 10^{14}[/tex]
[tex]E=4.68\times 10^{-19}\ J[/tex]
So, the energy of exactly one photon of this light is [tex]4.68\times 10^{-19}\ J[/tex]. Hence, this is the required solution.
In the given question, [tex]\rm 4.68 \times 10^{-19}[/tex] J is the energy of exactly one photon of light with a frequency of [tex]\rm 7.07 \times 10^{14} Hz[/tex].
Energy refers to the capacity or ability to do work or cause change. It is a scalar quantity that can be transferred or converted from one form to another, but it cannot be created or destroyed.
The energy of one photon of light is given by the equation:
[tex]\rm E = hf[/tex]
where E is the energy of the photon,
h is Planck's constant, and
f is the frequency of the light.
Plugging in the given frequency of [tex]\rm 7.07 \times 10^{14} Hz[/tex], we get:
E = [tex]\rm (6.626 \times 10^{-34}\ J s) \times (7.07 \times 10^{14}\ Hz)[/tex]
E = [tex]\rm 4.68 \times 10^{-19}[/tex] J
Therefore, the energy of exactly one photon of light with a frequency of [tex]\rm 7.07 \times 10^{14} Hz[/tex] is [tex]\rm 4.68 \times 10^{-19}[/tex] J.
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As you travel from a solid to a gas, energy is being absorbed or given off?
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Which of the statements correctly describes the reactivity of halogens, according to the octet rule?
They have two electrons in their valence shell, so halogens are very unreactive. They have seven electrons in their valence shell, so halogens are very unreactive. They have seven electrons in their valence shell, so halogens are very reactive. They have two electrons in their valence shell, so halogens are very reactive.
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Hope this helps! :)
Answer:
They have seven electrons in their valence shell, so halogens are very reactive.
Explanation:
The halogens are the elements of the group 17 (or 7A) of the periodic table, all the elements have the valence shell [tex]s^{2}p^{5}[/tex], so they have 7 electrons in their valence shell.
These elements need only one electron to be stable according to the octet rule, so they are very reactive, they can react with metals, non-metals, hydrogen and with themselves.
The average atomic masses of some elements may vary, depending upon the sources of their ores. Naturally occurring boron consists of two isotopes with accurately known masses (10B, 10.0129 amu and 11B, 11.0931 amu). The actual atomic mass of boron can vary from 10.807 to 10.819, depending on whether the mineral source is from Turkey or the United States. Calculate the percent abundances leading to the two values of the average atomic masses of boron from these two countries.
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Explanation:
Formula used to calculate average atomic mass follows:
[tex]\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i[/tex]
Let the fractional abundance of B-10 isotope be 'x'. So, fractional abundance of B-11 isotope will be '1 - x'
For B-10 isotope:
Mass of B-10 isotope = 10.0129 amu
For Li-7 isotope:
Mass of B-11 isotope = 11.0931 amu
1) Average atomic mass of boron = 10.807 amu
[tex]10.807 amu=x\times 10.0129 amu+(1-x)\times 11.0931 amu[/tex]
x= 0.2648
The percent abundances B-10 isotope = 0.2648 × 100 =26.48%
The percent abundances B-11 isotope = 100% - 26.48% =73.51%
2) Average atomic mass of boron = 10.819 amu
[tex]10.819 amu=x\times 10.0129 amu+(1-x)\times 11.0931 amu[/tex]
x= 0.2537
The percent abundances B-10 isotope = 0.2537 × 100 =25.37%
The percent abundances B-11 isotope = 100% - 25.37% =74.63%
how is the growth of a living thing different from the growth of a nonliving thing
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Growth is a permanent and Irreversible increase in the size of a living organism. In Living organisms, growth is from Inside. Where as in Non-living objects like Mountains and sand mounds, growth occurs by accumulation on of material on the outer surface.
What is Growth ?Growth is the increase in mass and size of a body or organs which typically occurs by the multiplication of cells and an increase in intracellular substance.
Development means the physiological and functional maturation of the organism.
Living organisms undergoes growth from Inside. Where as Non-living objects like Mountains and sand mounds undergo growth by accumulation on or of material on the outer surface.
Therefore, Growth is a permanent and Irreversible increase in the size of a living organism.Where as in Non-living objects like Mountains and sand mounds, growth occurs by accumulation on of material on the outer surface.
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which is the most accurate description of metals a. dull and brittle b. non reactive gases C. liquid at room temperature d. good conductors of electricity
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The correct answer is option (d). The most accurate description of metals are good conductors of electricity.
Metals are generally known for their ability to conduct electricity efficiently. This is due to the presence of free electrons in their structure, which can move easily through the metal, carrying electrical current.
Option a, dull and brittle, does not accurately describe metals. While some metals can be brittle, many are ductile and malleable. Additionally, metals can have a shiny appearance, which contradicts dull.Option b, non reactive gases, is incorrect because metals are not gases, and many metals are known for their reactivity, especially with acids and oxygen, leading to oxidation or corrosion.Option c, liquid at room temperature, is also incorrect because most metals are solids at room temperature, with mercury being a notable exception as it is a liquid at room temperature.What is an organ that absorbs water and vitamin K from digested food
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The organ that absorbs water and vitamin K from digested food is the small intestine.
The small intestine is a long, coiled tube that is located in the abdomen. It is responsible for the absorption of nutrients from digested food. The small intestine is divided into three parts: the duodenum, the jejunum, and the ileum.
The duodenum is the first part of the small intestine. It is about 10 inches long and is located just below the stomach. The duodenum is where most of the digestion of food takes place. The jejunum is the middle part of the small intestine. It is about 8 feet long and is where most of the absorption of nutrients takes place. The ileum is the last part of the small intestine. It is about 12 feet long and is where the remaining nutrients are absorbed.
Water and vitamin K are both absorbed in the small intestine. Water is absorbed throughout the small intestine, but it is absorbed more rapidly in the jejunum. Vitamin K is absorbed in the ileum.
Other nutrients that are absorbed in the small intestine include carbohydrates, proteins, fats, minerals, and vitamins. The small intestine is a very important organ for digestion and absorption of nutrients.
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which of the following characteristics must be present for a substance to be called a mineral?
a. have a crystal structure
b. has an unpredictable chemical structure
c. can be liquid or solid
d. can be organic or inorganic
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Answer:
A. have a crystal structure
Explanation:
A mineral has a definite chemical structure
It has to be a solid
A mineral is inorganic
The characteristics which must be present for a substance to be called a mineral is; Choice A: have a crystal structure.
Discussion:
The most definite characteristic of minerals is their unique Chemical Composition.
Each mineral has its own specific combination of atoms that cannot be found in any other mineral. For example, table salt is a mineral that consists of sodium and chlorine ions bonded together in a repeating pattern.
In addition, Minerals are inorganic and belong to no class of organic compounds.
Minerals are also solid.
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How do you know if a reaction is exothermic? Enter your answer in the space provided
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What new scientific evidence led to changes in daltons atomic theory
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Dalton has proposed that atoms were the smallest particles which make up matter. Then Thomson discovered the electron, which was even smaller than an atom!
Explanation:Thomson's experiments with cathode ray tubes helped him to discover the electron (which Dalton did not know about). Dalton thought that atoms were indivisible particles, and Thomson's discovery of the electron proved the existence of subatomic particles.
This ushered in a model of atomic structure referred to as the plum pudding model. I like to think of it like a sphere shaped chocolate chip cookie since plum pudding is not super popular in the US.
The cookie dough (they didn't know what it was yet) is positively charged and the chocolate chips (electrons) are negatively charged and scattered randomly throughout the cookie (atom). The positive and negative charges cancel producing a neutral atom.
Later discoveries by Rutherford and others lead to additional revisions to atomic theory.
John Dalton was the first to propose the atomic model that stated it to be the smallest particle. It was later replaced by J.J. Thomson's Plum pudding model.
What is the Plum pudding model?
Thomson proposed the plum pudding model after Dalton's atomic theory. It was an important discovery that stated that atoms to be consisting of charged particles.
The model nullified Dalton's claim of the atom being the smallest particle by discovering the sub-atomic particles, namely electrons, protons, and neutrons.
The protons carried a positive charge and neutral neutrons were spread all over the atom, whereas the negatively charged electrons were found embedded like plums or cherries in the sea of protons and neutrons.
Therefore, Thomson's plum pudding model nullified Dalton's atomic model.
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what is the body temperature in the Celsius scale the Fahrenheit scale and the Kelvin scale
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The normal body temperature in Fahrenheit is 98.6 degrees.
In Celsius, the normal body temperature is 37 degrees.
In Kelvin, the normal body temperature is 310 degrees.
Answer:
The normal body temperature in Fahrenheit is 98.6 degrees.
In Celsius, the normal body temperature is 37 degrees.
In Kelvin, the normal body temperature is 310 degrees.
Explanation:
if your sample contained a volatile impurity what value would be in error, the mass of the anhydrous salt or the mass of the water?
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The presence of a volatile impurity would cause the calculated mass of anhydrous salt to be too low, as the impurity would evaporate along with water, leading to an overestimation of the mass of water lost.
Explanation:If a sample contains a volatile impurity, the value that would be in error is the mass of the anhydrous salt. When heating a hydrated salt to drive off water and obtain the mass of the anhydrous salt, the presence of a volatile impurity means that along with the water, the impurity could also evaporate. This would lead to a recorded mass that is less than the actual mass of the anhydrous salt. So, the calculated mass of anhydrous salt would be too low, and conversely, the mass of water recorded would be too high because the loss of mass of the volatile impurity would be erroneously attributed to the water mass.
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Which element in Period 4 is the most chemically active non-metal?
Answers
Your answer is: Bromine
Have an amazing day!
Bromine will be the most chemically active non-metal in Period 4.
What is non-metal?A nonmetal is such a chemical element that typically doesn't have a lot of metallic characteristics; examples include colorless gases and glossy, solids with a high melting temperature.
What is bromine?Bromine is a kind of element that can be occurred in period 4 in the periodic table.
The atomic number of bromine is 35 and its electronic configuration is 2,8,18,7. it has 4 shells hence it will be placed in period 4.
Therefore, Bromine will be the most chemically active non-metal in Period 4.
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What explains the fact that no machine is 100 percent efficient?
A. Friction transforms mechanical energy into thermal energy.
B. Thermal energy is transformed into mechanical energy by friction.
C. Potential energy can be transformed into kinetic energy.
D. Kinetic energy can be converted into mechanical energy.
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what is true about the about the structure or function of the plasma membrane
A. large molecules often cross the plasma membrane while inside vesicles
B. Hydrophobic molecules keep the cell from getting too much water
C. The bilayer structure forms a solid boundery that seperates the cell from its enviornment.
D. its made entirely of intregral protiens.
Answers
Large molecules do not cross the membrane through vesicles but through carrier proteins. Option B. is entirely false as hydrophobic molecules never get in contact with water, they are 'water hating' unlike hydrophilic molecules.
The plasma membrane is made of both integral and peripheral proteins.
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Which describes interactions between substances and stomata during photosynthesis? Check all that apply.
Oxygen enters stomata.
Oxygen is released through stomata.
Carbon dioxide enters stomata.
Carbon dioxide is released through stomata.
Hydrogen enters stomata.
Hydrogen is released through stomata.
Answers
Carbon dioxide enters the stomata and Oxygen is released through the stomata during photosynthesis.
What is photosynthesis?Photosynthesis is the process that takes place in plants through photosynthetic pigments such as chlorophyll. All green plants utilize photosynthesis to produce nutrients by using water, carbon dioxide, and sunlight. The side product of the photosynthesis process in plants is oxygen.
The photosynthesis process is also used by algae to change solar energy into chemical energy. Photosynthesis takes place when plants use sunlight to convert carbon dioxide and water into glucose and oxygen.
There are a large number of tiny pores on the surface of the leaves of plants known as stomata. The carbon dioxide (CO₂) enters the leaves of the plant through the stomata and oxygen leaves through the stomata present on the surface of the leave.
Therefore, options (B) and (C) are correct to describe interactions between substances and stomata.
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