Final answer:
The solubility of KCl in ethanol is 0.25 g/100 mL at 25°C. Compared to the solubility of KCl in water, KCl is much more soluble in water than in ethanol.
Explanation:
The solubility of KCl in ethanol is 0.25 g/100 mL at 25°C. This means that at this temperature, 0.25 grams of KCl can dissolve in 100 mL of ethanol. Comparing this to the solubility of KCl in water, we can see that the solubility of KCl in water is generally much higher. While the solubility of KCl in ethanol is 0.25 g/100 mL, the solubility of KCl in pure water at 25°C is 27.8 g/100 mL. Therefore, KCl is much more soluble in water than in ethanol.
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
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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----------------- are made using the metalloids silicon and germanium
A certain shade of blue has a frequency of 7.07 × 1014 Hz. What is the energy of exactly one photon of this light?
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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Which concern is the LEAST important when using a compound light microscope to view a sample of paramecia? A) obtaining good resolution B) obtaining sufficient contrast C) recognizing the subject when one sees it D) having sufficient magnification available..........................THE ANSWER IS D....stg
Answer:
D)
Explanation:
The compound light microscope is a microscope that has more than one lens and its light source. Because of the various lens presented, having a sufficient magnification is not a concern.
However, only magnification doesn't indicate that it will be possible to view a sample, it's necessary some contrast to separate all the species presented, a good resolution (so the sample will be the focus), and also recognizing the subject when one sees it.
Which is more reactive copper or calcium? Why?
Answer:
Calicum
Explanation:
This is true because calcium loses more electrons and is a group 2 metal
WHICH OF THESE IS NOT A CHARACTERISTIC OF A MINERAL
The incorrect characteristic for a mineral among the listed options is that they are inexhaustible. Minerals are natural, inorganic, have a definite composition, and can have an uneven distribution, but they are not unlimited resources. So, the correct option is C.
The characteristic of a mineral that is not accurate among the options provided is C) They are inexhaustible. Minerals are indeed created by natural processes, they have a defined chemical composition, and their distribution is uneven. However, minerals are not inexhaustible. They are formed under specific geological conditions and can be depleted through mining and use.
Minerals are defined as naturally occurring, inorganic solids with a definite chemical composition and a characteristic crystalline structure. These solid substances are identified by certain physical properties such as hardness, density, and color. While minerals are integral to industrial applications and the formation of rocks, they must be naturally formed to be considered true minerals. This means synthetic products like laboratory-created diamonds, although similar in characteristics, are not classified as minerals.
Furthermore, while some minerals are abundant, many are limited and can run out, especially those that are mined extensively for human use. Therefore, the notion that minerals are inexhaustible is incorrect because it implies that they can be used without limit, which is not sustainable given the finite quantities in which they exist in the Earth's crust.
Complete Question:
Which one of the following is not a characteristic of minerals :
1. Naturally occurring
2. Definite chemical composition
3. Inexhaustible
4. Distribution is uneven
The red arrow is pointed at different locations of an atom of Helium. Where is it pointing to the GREATEST concentration of atomic mass?
The most dense part of an atom is its nucleus. Almost all of the mass in an atom is made up from the protons and neutrons in the nucleus with a minimal contribution from the orbiting electrons.
Helium atom has two orbital electrons and two protons and two neutrons in nucleus. It has 4 atomic mass and 2 atomic numbers. So, the greatest concentration of atomic mass is in nucleus.
Which state of matter undergoes changes in volume most easily
The state of matter that undergoes changes in volume most easily is gas.
The state of matter is the organization and movement of the constituent particles (atoms, molecules, or ions) and the forces between them.
Gas undergoes change in volume because the particles in a gas are free to move in all directions and are not held together by strong intermolecular forces.
As a result, gas particles can spread out to fill the container they are in, and they can be compressed or expanded relatively easily.
Therefore, gas is the state of matter that undergoes changes in volume most easily because the particles in a gas are free to move and are not bonded together by strong intermolecular forces.
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What is an organ that produces enzymes that break down nutrients
The organ responsible for producing enzymes that break down nutrients is the pancreas.
The pancreas is a vital organ located in the abdomen, with both endocrine and exocrine functions. In its role as an exocrine gland, the pancreas secretes digestive enzymes into the small intestine to aid in the breakdown of carbohydrates, proteins, and fats from the food we consume.
These enzymes, including amylase, protease, and lipase, are crucial for the proper digestion and absorption of nutrients. The pancreas plays a central role in maintaining the body's metabolic balance and ensuring that the nutrients from the food we eat can be effectively utilized by the body's cells. Dysfunction of the pancreas, such as in conditions like pancreatitis or pancreatic cancer, can lead to impaired digestion and nutrient absorption, emphasizing the essential role this organ plays in our overall health.
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what did earnest Rutherford's gold foil experiment demonstrate about atoms
Final answer:
Rutherford's gold foil experiment showed that atoms have a small, dense nucleus at the center with electrons orbiting around it in mostly empty space.
Explanation:
Rutherford's gold foil experiment demonstrated that atoms have a small, dense nucleus at the center, surrounded by mostly empty space where electrons orbit. He bombarded thin sheets of gold foil with alpha particles, which are positively charged particles with a mass four times that of a hydrogen atom.
According to Rutherford's expectations, most of the alpha particles passed through the gold foil un-deflected. However, he observed that around one in 20,000 alpha particles deflected at larger angles, indicating the presence of a tiny but very dense region in the center of the atom, which was later named the nucleus. This discovery challenged the prevailing plum pudding model of the atom, leading to a new understanding of atomic structure.
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.
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.
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.
what is the body temperature in the Celsius scale the Fahrenheit scale and the Kelvin scale
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:
Which of the following animals exhibits bilateral symmetry?
1. Coral
2. Jelly fish
3. Starfish
4. Sea horse
Need help quick!! Please
Answer is: 4. Sea horse.
Seahorse is species of small marine fishes in the genus Hippocampus.
A seahorse has a bilateral line of symmetry, if it cut along a central axis, the left and right half would be congruent.
In bilateral symmetry or plane symmetry, the sagittal plane divides an organism into roughly mirror image halves.
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
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]
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
Scientific models can never be changed. Please select the best answer from the choices provided T F
Answer : False
Explanation : Scientific models can never be changed this statement is False.
As these scientific models are based on current scientific knowledge and may have to be changed when new discoveries are made. They were not a replacement for experimentation, rather they were used in conjunction with experimentation to further understanding of a concept, event, or process. It has to be changed when the scientific understanding changes.
What new scientific evidence led to changes in daltons atomic theory
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 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.
How do you know if a reaction is exothermic? Enter your answer in the space provided
Which graph shows negative acceleration?
Graph A
Graph B
Answer:
Graph B
Explanation:
the line is negative as it is travelling donwards
Density is an intensive property in that increasing the amount of a substance _________ increase its density.
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.
There are more protons than electrons in a negatively charged atom.true or false. it is false, pretty sure
Answer: false
Explanation:
I got it right
i need it assap
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.
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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what is the noble gas notation for the element indium, (in,atomic #49) is
Which element in Period 4 is the most chemically active non-metal?
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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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.
balance the combustion eqation; __C5H + __O2 ---> __CO2+__H2O
a mineral that breaks into irregular pieces is said to show which of the following?
a. cleavage
b. fracture
c. luster
d. hardness
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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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.
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%