Which type of substance is graphene?
A-atom
B- molecule
C-compound
Will mark brainliest
Answer: B- molecule
Explanation:
An atom is the smallest entity of a substance which may or may not have independent existence.
Molecule is a pure substance which is composed of similar kind of atoms.It can not be decomposed into simpler constituents using chemical reactions.Example: Hydrogen [tex]H_2[/tex]
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water [tex]H_2O[/tex]
Graphene is a crystalline allotrope of carbon and thus is a molecule as it is made up of similar kind of atoms.
How do the independent and dependent variables in an experiment compare?
Answer:
The independent variable controls the dependent variable.
Explanation:
Which of these actions isn’t part of your body’s homeostasis? A. Sweating when your hot B. Breathing harder when u excercise C. Smiling when you’re happy or D. Going to the bathroom
Answer:
C. smiling when you're happy
Explanation:
SInce it's just an emotion and isn't actually that nessary
scientists build theories to test their ideas about things that they cannot observe directly true or false?
Which of these is a physical property?
Question options:
malleable
easy to digest
does not burn
becomes moldy quickly
how many atoms of oxygen are contained in 47.6g of Al2(CO3)3? The molar mass of Al2(CO3)3 is 233.99g/mol.
how do you know if a reaction is exothermic
A chemist isolates an element that is suspected to have a principal quantum number equal to 5. What is the maximum number of electrons that can occupy this level?
The maximum number of electrons that can occupy the principal quantum number 5 is 50, calculated using the formula 2n² where n is the principal quantum number.
Explanation:The maximum number of electrons that can occupy the fifth energy level (n = 5) of an atom is determined by the formula 2n2. For n = 5, this formula gives:
2 × 52 = 2 × 25 = 50 electrons
Therefore, the maximum number of electrons that can occupy the principal quantum number 5 is 50. This includes the possible subshells in that energy level: 5s, 5p, 5d, and 5f, with the number of orbitals in each subshell being one s-orbital, three p-orbitals, five d-orbitals, and seven f-orbitals, respectively.
What was rutherfords contribution to the structure of an atom
The Nuclear Model-1909
While visiting the Grand Canyon, you observe the exposed layers of rock in the valley. What natural process most likely caused the valley to form? Deposition Chemical weathering Oxidation Erosion
Answer: it would be erosions
Explanation:
The natural process most likely caused the valley to canyon is tectonic uplift and erosion.
What is tectonic uplift?Tectonic uplift is defined as the portion of the total geologic uplift to the mean of the earth surface that is not attributable to an isostatic response to an unloading.
Tectonic plate is defined as a scientific theory explaining how large landforms are formed as a result of subsurface motions on Earth.
Erosion is defined as the geological process in which earthen materials will move away and transported by the natural force such as wind and water.
There are basically two types of erosion
Surface erosionMass movement erosionThus, the natural process most likely caused the valley to canyon is tectonic uplift and erosion.
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The molecules in compound AB are strongly polar, while the molecules in compound XY are non polar. Which substance probably has a higher boiling point
what is the volume, in liters, of 2.00 moles of hydrogen H at STP
Final answer:
To find the volume of 2.00 moles of hydrogen gas at STP, multiply the number of moles by the standard molar volume, 22.4 L/mol, resulting in 44.8 liters.
Explanation:
The volume of hydrogen gas at STP (Standard Temperature and Pressure) can be found using the standard molar volume. By definition, the standard molar volume of an ideal gas at STP, which is 0°C (273 K) and 1 atm pressure, is 22.4 liters per mole.
For 2.00 moles of hydrogen gas at STP, the calculation simply involves multiplying the number of moles by the standard molar volume:
Volume = 2.00 moles × 22.4 L/molVolume = 44.8 litersThus, 2.00 moles of hydrogen gas at STP occupy a volume of 44.8 liters.
Water particles in gas coming off a pan of boiling water are moving faster or slower than the particles of the water in the pan
Answer:
faster.
Explanation:
Particles of water in the gas coming out of a pot of boiling water are moving faster than particles of water in the pot.
This is because the heat energy makes the molecules move faster, so the molecules "trapped" in the liquid are able to gradually break down the barriers of the liquid-air interface and, therefore, the amount of water. it decreases until it "disappears". When you boil water, that smoke you see coming out is nothing more than a bunch of molecules that have broken through the barrier and are free, gaseous. This was due to the rapid movement of these molecules.
We want to see what happens to the particle's speed in a given material as the temperature changes (increases in this case) and it faces a change of phase.
We will see that the particles in the gas (vapor of water) have a larger speed than the ones in the liquid water.
--------------------------------
To see this, first, we need to understand how the temperature manifests in a given material.
As we increase the temperature of the material, the kinetic energy of the particles that make the material increase (thus the speed increases). This causes the particles to move more, and this is why as we increase the temperature, is likely to see an increase in the volume.
This is the reason of why we usually see that a solid has less volume than a liquid, and a liquid has less volume than a gas (for the same mass of the same material).
Then as we increase the temperature of liquid water and that water starts to change of phase (by boiling) the kinetic energy of the particles increase, and thus, the speed increases.
Then the particles will be moving faster than the particles of the water in the pan.
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What is the smallest part of Substance called?
A. Element
B. Atom
C. Mixture
D. Molecule
Please help! ☺️
Living organisms all have DNA and RNA which are both _______
How do I identify the ions present in K2HPO4?
Final answer:
In K2HPO4, the ions present are potassium ions (K+) and hydrogen phosphate ions (HPO42-). Hydrogen phosphate can further dissociate, but the dissociation leading to the formation of PO43- is much less due to the small value of the equilibrium constant. Hence, the solution is basic.
Explanation:
To identify the ions present in K2HPO4, we first consider the fact that K2HPO4 is a salt derived from the reaction of a strong base (KOH) with a weak acid (H3PO4), and it is made up of potassium ions (K+) and hydrogen phosphate ions (HPO42-). In aqueous solution, K2HPO4 fully dissociates into these ions:
K2HPO4 (s) → 2 K+ (aq) + HPO42- (aq)
The potassium ions, K+, are the cationic species and the HPO42- ions are the anionic species. The hydrogen phosphate ion is an amphiprotic species, meaning it can act as both an acid and a base. This ion may further dissociate in water:
First ionization: H2PO4- (aq) → H+ (aq) + HPO42- (aq)
Second ionization: HPO42- (aq) + H2O(l) ⇌ H3O+ (aq) + PO43- (aq)
However, the second ionization, which forms PO43- and H3O+, has an equilibrium constant (K2), which is much less than that of the first ionization, indicating that it occurs to a significantly lesser extent. The solution of K2HPO4 is basic because the K2 of the HPO42- ion is much larger than the acidic dissociation constant.
To squeeze a gas into a smaller space you
the half-life of U234 is 25200 years. How much of a 100 gram sample remains after 352800 years?
Write a brief explanation about why a plant extract is a mixture
A plant extract is a mixture due to the fact that it contains multiple compounds physically combined, they retain their individual characteristics. This makes the composition of extracts heterogeneous. Mixtures in the form of plant extracts are especially important in pharmaceutical science.
Explanation:A plant extract is considered a mixture due to the fact that it contains multiple compounds physically combined, not chemically bonded. These compounds usually include various elements of the plant like oils, pigments, and other organic molecules, all present in varying amounts. The plant extract retains the characteristics of its individual components because they are not chemically reacting with one another, but simply mixed together, making it a heterogeneous mixture, as the same drop of the extract might have different compounds in different proportions.
This is not much unlike the example of an Italian dressing, where in different parts of the mixture you may find more oil or vinegar or herbs because the ingredients separate and settle unevenly throughout the mixture. Similarly, in a plant extract, the compounds will not be proportionately arranged in every drop of the mixture.
Particularly in pharmaceutical science, this heterogeneous nature is an advantage as different plants contain unique combinations of beneficial compounds. Examples include medicines such as aspirin and codeine, which were once derived from plant extracts. This demonstrates the importance of mixtures in medicinal applications.
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How many molecules are in each sample?4.6 g H2O
Answer: The number of molecules present in given amount of water are [tex]1.54\times 10^{23}[/tex]
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of water = 4.6 g
Molar mass of water = 18.0 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of water}=\frac{4.6g}{18.0g/mol}=0.255mol[/tex]
According to mole concept:
1 mole of a compound contains [tex]6.022\time 10^{23}[/tex] number of molecules.
So, 0.255 moles of water will contain [tex]0.255\times 6.022\times 10^{23}=1.54\times 10^{23}[/tex] number of molecules.
Hence, the number of molecules present in given amount of water are [tex]1.54\times 10^{23}[/tex]
Which of the answer choices correctly identifies a scenario that displays evidence a chemical reaction is occurring?
Paper absorbs liquid and sinks.
Sugar burns and turns black.
Water boils and evaporates.
Glass vibrates and shatters.
Answer: Option (b) is the correct answer.
Explanation:
A chemical reaction is the one in which there occurs change in the chemical composition of a substance in order to result in the formation of a new compound.
For example, when sugar burns then it means it is chemically reacting due to which it turns into black.
On the other hand, a physical change is the one in which there occurs no change in chemical composition of a substance. As a result, no new compound is formed.
For example, Paper absorbs liquid and sinks, Water boils and evaporates, and Glass vibrates and shatters are all physical changes.
Thus, we can conclude that sugar burns and turns black correctly identifies a scenario that displays evidence a chemical reaction is occurring.
Some common substances used in the laboratory are listed in the table. The chemical formulas of the substances are also listed beside their names.
How many of the listed items are elements?
Answer:5
Explanation:
5
Copper, sulfur, gold, iron, and aluminum are elements, as their symbols suggest. The other four substances are compound with two elements each.
Difference between osmosis and diffusion
Osmosis occurs through a semipermeable membrane
Net movement in osmosis is from areas of higher concentration to areas of lower concentration
Osmosis requires facilitation by an energy carrying molecule, such as ATP. Diffusion requires no additional energy to move molecules across the concentration gradient.
Osmosis is used for gases, such as oxygen and carbon dioxide. Diffusion is used for water that contains salt or sugar molecules.
PLEASE NO GUESSING OR INCORRECT ANSWERS.
How many grams of magnesium oxide can be produced when 97.2 g Mg react with 88.5 g O2?
Unbalanced equation: Mg + O2 → MgO
Herbicides:
1.are used to kill insects
2.can increase crop yields by killing weeds
3.supply plants with nutrients and minerals
4.are only used with hybrid plants
Answer:
The correct answer is number 2: herbicides can increase crop yields by killing weeds.
Explanation:
Herbicides are chemiclas used to avoid the spreding of undesired plants (weeds) on crops. These weeds would be prejudicial to the harvest, therefore, herbicide use can increase crop yields.
As an environmental engineer how would you apply the process of separating mixtures to clean up a polluted beach? What would you do first? Second? Third? What equipment would you need? Explain your process.
Radioactive isotopes of an atom are?
Radioactive isotope, also called radioisotope, radionuclide, or radioactive nuclide, any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.
Answer:
Less stable
Explanation:
I took the K12 test
What does the law of conservation say about matter?
How are osmosis and diffusion alike
Both processes can occur though semipermeable membranes
Both levees can occur though permeable bilayer membranes
Both require additional energy provided by channel proteins
Botha low solute molecules to move across a semipermeable membrane
Answer: Option A
Explanation:
The osmosis can be defined as a biological process where the movement of the particles takes place through the semipermeable membrane.The solvent moves from a region of high concentration to low concentration.
The diffusion is same in the reference that it can also occur through the semipermeable membrane.
The particles from the higher concentration moves towards the lower concentration.
Hence, option A is correct.
Does H₂O have a subscript?