Which of these substances are molecules?
1. H2O
2. NaCl
3. N2
4. O2
Question 12 options:
3 and 4
All of them
1 and 2
None of them
The answer is; All of them
A molecule is a stable chemical unit (with neutral charge) of atoms chemically bonded together (these bonds can be covalent, metallic, ionic, and etcetera). The molecule can, therefore, be of an element (contain atoms of the same element – in this case, N2 and O2) or a compound (atoms of different elements- in this case, H2O and NaCl).
What is hydrolysis,and what type of weathering is it
What mass of water is required to react completely with 157.35 g CO2?
Answer:64.43g H2O
Explanation: the other one is wrong
Element A has seven valence electrons. How does its reactivity compare to that of element B, which has four valence electrons?
Answer:
The correct answer is "Element A is more reactive".
Explanation:
The missing options of this question are:
Element A is more reactive.
Element A is less reactive.
Element A and B have the same reactivity.
Element A has no reactivity.
The correct answer is "Element A is more reactive".
Valence electrons are defined as outer shell electron that can participate in the formation of chemical bonds with other atoms. The atoms tend to have either 0 or 8 valence electrons. Therefore, depending in the number of valence electrons, an atom can either give their valence electrons (1 to 3 electrons) or try to take more valence electrons (4 to 7 electrons). Element A with 7 valence electrons is more reactive that Element B with 4 valence electrons, because Element A only needs 1 more electron to full its 8 valence electrons.
A galvanic cell is made up of an aluminum electrode and a sodium electrode. Which metal is oxidized?
In a galvanic cell composed of aluminum and sodium electrodes, sodium is the metal that is oxidized because it has a more negative standard electrode potential, indicating a tendency to lose electrons more readily than aluminum.
In a galvanic cell, the metal that is oxidized is the one that loses electrons. Oxidation takes place at the anode of the cell. To determine which metal is oxidized between aluminum and sodium in a galvanic cell, we consider their standard electrode potentials. The metal with the more negative standard electrode potential tends to lose electrons and get oxidized. In this case, aluminum has a standard reduction potential of -1.66 V, while sodium has a standard reduction potential of -2.71 V. Since aluminum is less negative, it is the more noble metal and is less likely to lose electrons compared to sodium.
Therefore, in a galvanic cell made up of an aluminum electrode and a sodium electrode, sodium will be the metal that is oxidized. This is because sodium has the more negative standard electrode potential and, consequently, a greater tendency to lose electrons. The half-reaction for sodium at the anode would be
Na(s) ⇒ Na⁺(aq) + e⁻.
In contrast, aluminum will be reduced at the cathode in this cell.
Which group on the periodic table contains only metals? the second group
A.
the last group
B.
along the top
C.
along the bottom
D.
The answer is the second group :)
Determine the enthalpy for this reaction: Al(OH)3(s)+3HCl(g)→AlCl3(s)+3H2O(l)
To calculate the enthalpy of the given reaction, understanding of stoichiometry, bond energies and the concept of enthalpy changes in chemical reactions is utilized. The reaction has stoichiometric amounts of reactants, leads to formed stronger bonds in the products, and is exothermic.
Explanation:To determine the enthalpy for the given reaction: Al(OH)3(s)+3HCl(g)→AlCl3(s)+3H2O(l), firstly, for the reaction of 0.0500 mol acid (HCl), we know that q = -2.9 kJ. Since the reactants are provided in stoichiometric amounts (the same molar ratio as in the balanced equation). The enthalpy change is proportional to the amount of acid neutralized: ΔH = -2.9 kJ/0.0500-mol HCl.
Use the standard molar enthalpy of formation of HCl(g), ΔH, of -92.307 kJ/mol. This excess energy is released as heat, indicating that this reaction is exothermic. The bond formation and breaking are a part of this process, creating H-Cl bonds which release more energy than they consume.
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How many grams of CaCl2 are in 250 mL of 2.0 M CaCl2?
How many moles of KNO3 are in 500 mL of 2.0 M KNO3?
1 mol KNO3
How many grams of CaCl2 are in 250 mL of 2.0 M CaCl2?
55 g CaCl2
What volume of a 6.67 M NaCl solution contains 3.12 mol NaCl? 0.468 L
Which of the following statements does not describe the structure of an atom?
Inside the nucleus of an atom are protons and neutrons.
Protons are positively charged sub-atomic particles.
Electrons are negatively charged sub-atomic particles.
Most of the mass of an atom comes from the electron cloud.
Answer:
Most of the mass of an atom comes from the electron cloud
Explanation:
Protons are positive, Electrons are negative, and there are only protons and neutrons in the nucleus of an atom. Also there are only 6 electrons in a electron cloud and the mass of an electron is 1/1,836 the mass of a proton. So it would be the last answer.
Regarding the structure of an atom, it is false that most of the mass of an atom comes from the electron cloud.
Let's consider which of the following statements does not describe the structure of an atom.
Inside the nucleus of an atom are protons and neutrons. TRUE. The nucleus is formed by protons and neutrons surrounded by the electron cloud. Protons are positively charged sub-atomic particles. TRUE. The relative charge of protons is +1. Electrons are negatively charged sub-atomic particles. TRUE. The relative charge of electrons is -1. Most of the mass of an atom comes from the electron cloud. FALSE. The mass of electrons is negligible in comparison with protons and neutrons. Most of the mass of the atom comes from the nucleus.Regarding the structure of an atom, it is false that most of the mass of an atom comes from the electron cloud.
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Water plays a key role in chemical weathering by
a.
dissolving minerals
c.
contributing to the oxydation process
b.
transporting minerals
d.
all of the above
To function on their own, unicellular organisms must do what?
Make tissues
Perform a specialized task
Work with other cells
Do all jobs for survival
PLEASE NO INCORRECT ANSWERS AND PLEASE ANSWER QUICKLY
What Element is found in column 16, period 2?
describe one way lack of water affect cell function
During the hot summer days, there is a lot more water in the air. This is due to which change of state?
Condensation
Evaporation
Sublimation
Freezing
In evaporation particles of water take energy in the form of sunlight from the surrounding and then convert into vapor phase. Therefor evaporation is the only reason for the lot more water in air in summer
What is evaporation?Evaporation is a physical process in which the water in liquid state converts to gaseous state at the temperature below its boiling point. Evaporation happens before the boiling process.
Evaporation causes cooling effect in the surrounding. During summer when water is kept in earthen pot water cools, this is because of the evaporation process
Evaporation is affected by temperature. As the temperature increases the rate of evaporation increases and hence in summer there is more evaporation and hence there is lot more water in air
Therefor evaporation is the only reason for the lot more water in air in summer
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Final answer:
The increased water in the air during hot summer days is a result of evaporation, where the sun's heat transforms liquid water into water vapor increasing the humidity in the air.
Explanation:
During hot summer days, the increased water in the air is primarily due to the change of state called evaporation. Evaporation is a process where liquid water on Earth's surface, like lakes and rivers, absorbs heat from the sun and transforms into water vapor. This vapor then enters the atmosphere contributing to the higher humidity we experience during summer times.
Evaporation happens when the sun heats the water, providing energy for the water molecules to escape from the liquid's surface into the air as vapor. It is one of the critical phases in the water cycle, and unlike condensation, which is the change of water vapor into a liquid, evaporation changes liquid into gas. This process is essential as it contributes to cloud formation and precipitation, playing a vital role in weather patterns and ecosystems.
which of these is a mixture?
salad
sugar
water
potassium
Answer:
salad
Explanation:
A mixture is a substance that combines two or more substance that are physically combined. A mixture can be easily seperated by a physical means . A mixture is the combination of various substances that are not chemically combined .Examples of mixtures are cake and salad . The cake contains various substances like egg, flour and sugar. This mixture can be easily separated into it individual entities by a physical means .
Base on the option the only mixture among the option is salad . Salad is a a mixtures that combines substances like tomatoes , fruits and vegetable. The individual substances that makes up the salad can be easily separated.
Sugar is a compound . Water is a compound as it contains two elements and potassium is an element.
Determine the theoretical yield of H2S (in moles) if 32 molAl2S3 and 32 molH2O are reacted according to the following balanced reaction. A possibly useful molar mass is Al2S3 = 150.17 g/mol.
Al2S3(s) + 6 H2O(l) → 2 Al(OH)3(s) + 3 H2S(g)
For the given reaction, 1 mole of Al2S3 produces 3 moles of H2S. Therefore, 32 moles of Al2S3 can produce 96 moles of H2S. This is the theoretical yield of H2S for this reaction.
Explanation:The balanced chemical equation given is Al2S3 + 6H2O → 2Al(OH)3 + 3H2S. From this equation, you can see that 1 mole of Al2S3 produces 3 moles of H2S. Therefore, if you have 32 moles of Al2S3, theoretically you can produce 3 x 32 = 96 moles of H2S. This is the theoretical yield of H2S for the given reaction, assuming that the reaction goes to completion with no side reactions.
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The substance that gets broken down in a homogeneous mixture is the (A)colloid (B)solution (C)solvent (D)solute
How does atomic radius change within groups and across periods in the periodic table
how can deforestation Both decrease the amount of oxygen in the atmosphere and increase the amount of carbon dioxide in the atmosphere
Please help!
If it's right I'll give you extra points for it.
is C and D an answer?
\
What mass of oxygen (O2) forms in a reaction that forms 15.90 g C6H12O6?
16.94 grams of oxygen is the correct answer
1.which of the following correctly describes carbon, represented by c?
It is an element because it is made of atoms that are all the same type
It is a compound because it is made of different types of atoms that are chemically joined together.
It is a mixture because it is made of different type of atoms that are not chemically joined together.
2. Which of the following correctly describe carbon dioxide represented by CO2
It is an element because it is made of atoms that are all of the same types
It is a compound because it is made of different types of atoms that are chemically joined together.
It is a mixture because it is made of different types of atoms that are not chemically joined together.
An atom has 16 protons and 16 neutrons. Which of the following could be the symbol for that atom, including its mass numbe? Consult the periodic table.
A. 35CL
B. 32S
C. 32Cl
D. 35S
Answer:
Option b. 32S
Explanation:
Given:
No. of protons = 16
No. of neutrons = 16
Atomic number of an element is equal to the number of protons present in it.
Therefore, atomic number of the element = 16
Mass number of the element is equal to sum of number of protons and neutrons.
Therefore, Mass number = 16 + 16 = 32
Element 'S' has atomic number 16 and its mass number is 32.
So among the given options, option b is correct.
Which of the following provides evidence that supports the continental drift theory? PLEASE HELP 10 POINTS
A.) fossils of the same organisms found in different continents
B.) magnetized rocks that do not match with the poles
C.) seafloor spreading
D.) volcanic activity
Answer: A) Fossils of the same organisms found in different continents
Explanation: Continental drift is a theory, according to which, for a long period of time, continents moved one against the other across the ocean bed. This theory has been developed by several scientists, supplemented, rewritten, etc, but in essence this theory is explained by the theory of the tectonic plate, that is, the continents move by floating on the plates of the Earth's lithosphere. Evidence for this are similar fossils, animal and plant, found on different continents, which means that they were formed once on the same, one continent, before the separation and floating of continents one in relation to the other.
The statement 'fossils of the same organisms found in different continents' provides evidence that supports the continental drift theory (Option A).
The continental drift theory proposed by Alfred Wegener (1915) posits that current continents were once part of a single landmass known as Pangea.According to this theory, Pangea began to broke into two major landmasses (i.e., Laurasia and Gondwana) million years ago, which formed the current continents and drifted to their current locations.There are different fossils belonging to the same taxonomic group that can be found on separate continents, thereby supporting the idea of continental drift.In conclusion, the statement 'fossils of the same organisms found in different continents' provides evidence that supports the continental drift theory (Option A).
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This is a model of a normal chromosome
at the freezing point, the particles in an object have no kinetic energy. true or false?
The assertion that particles in an object at its freezing point have no kinetic energy is false. At the freezing point, the particles' motion is significantly reduced, but it is not completely eliminated. As a result, the particles maintain some level of kinetic energy.
Explanation:In physics, the statement 'at the freezing point, the particles in an object have no kinetic energy' is false. Kinetic energy is the energy an object possesses due to its motion. When a substance reaches its freezing point, its particles are still in motion, but at a slower rate. They continue to vibrate, rotate, and occasionally move from place to place, although at a slower pace than in a liquid or gaseous state, reflecting that they still possess kinetic energy, albeit at a reduced level.
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a model is any representation of an object or
URGENT PLEASE HELP!!!
During an investigation a scientist heated 27 g of mercuric oxide till it decomposed to leave a dry product. The total mass of the product formed was 25 g. Does the law of conservation of mass hold true in this case? Use complete sentences to justify your answer based on numerical calculations.
Answer:Yes, the law of conservation of mass is true because even though some/2grames of mass was not there to end the 2 grams might have evaporated or escaped.
Explanation:
I got this right on flvs and more explanation is up there kinda. hope this helps
When u heat a pot of water over a flame what form of energy is added to water
Answer:
Thermal Energy
Explanation:
moles of phosphorous in 15-35-15 fertilizer in 10g
The composition of a fertilizer is usually express in NPK number. NPK number is in terms of Percent by mass of the said element which are Nitrogen, Phosphorus and Potassium. A 15-35-15 fertilizer has 15% Nitrogen, 35% Phosphorous, and 15% Potassium by mass. If you have 10 g of this fertilizer, to get the number of moles of phosphorus, you multiply the mass by 35%, which is equal to 10*0.35 or 3.5 g phosphorus. Then you divide the calculated mass of phosphorous by its molar mass which is 30.97 g/mol. Therefore, you have 3.5/30.97 which is equal to 0.1130 mol Phosphorus. This is the amount of Phosphorus in moles in the fertilizer.