True- Alchemists tried to turn metals into gold. True-If the medicines have been evaluated using unbiased tests.
Which of the following is alchemy?True- A medieval pseudoscience that tried to find ways to change ordinary metals into gold.
Alchemy is a historical philosophical and proto scientific tradition that was practiced in China, India, the Muslim world, and Europe. It is an old branch of natural philosophy also.
In the early few centuries AD, a handful of pseudo epigraphical works produced in Greco-Roman Egypt are the first to mention alchemy in its Western form.
Which inference can be made from the fact that Fritz Haber received a Nobel Prize in 1918
The Haber-Bosch process was used to make explosives in World War I and The Haber-Bosch process was an important scientific development.
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the empirical formula is C6H6O.vapour density is 47.find the molecular formula
Answer: The molecular formula will be [tex]C_6H_6O[/tex]
Explanation:
Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.
Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.
The empirical formula is [tex]C_6H_6O[/tex]
The empirical weight of [tex]C_6H_6O[/tex] = 6(12)+6(1)+1(16) = 94 g.
The molecular weight = [tex]2\times \text{vapour density}=2\times 47=94[/tex]
Now we have to calculate the molecular formula.
[tex]n=\frac{\text{Molecular weight}}{\text{Equivalent weight}}=\frac{94}{94}=1[/tex]
The molecular formula will be=[tex]1\times C_6H_6O=C_6H_6O[/tex]
Which statement is best illustrated in the diagram above regarding how the Sun's energy affects the Earth's surface from June through September in the Northern Hemisphere? The season changes from autumn to winter, daylight hours decrease, and infrared radiation is the weakest during the June solstice. B The season changes from winter to spring, daylight hours increase, and infrared radiation is the weakest during the September equinox. C The season changes from summer to autumn, daylight hours decrease, and infrared radiation is the strongest during the June solstice. The season changes from spring to summer, daylight hours increase, and infrared radiation is the strongest during the September equinox.
Answer:
I'm sorry but there is no diagram above.
If I react 4.2mol N2 with H2, how many moles of NH3 would I produce?
Answer:
first balance the reaction
n2 + 3h2 --> 2NH3
then you have your ratios
so for every mole of N2 you get 2 NH3
so 8.4mol is your answer
Explanation:
Why might an increase in the concentration of greenhouse gases be a concern? What
might be the effect of an increase? Use the diagram to help you answer.
Answer:
too many greenhouse gases can cause the temperature to increase out of control. ... The increased greenhouse effect is causing changes in our planet that can affect our lives. The major Greenhouse Gas, carbon dioxide, emitted naturally and by the burning of fossil fuels, stays in the atmosphere a long
Effects: By increasing the concentration of greenhouse gases in the atmosphere, we’re amplifying the planet’s natural greenhouse effect and turning up the dial on global warming.
The atmosphere of the Earth may begin to trap more and more heat if these greenhouse gases are present in excess. Earth warms as a result of this.
What are Greenhouse gases?A greenhouse gas is a gas that produces the greenhouse effect by both absorbing and emitting radiant energy at thermal wavelengths that are infrared. The five main greenhouse gases in the atmosphere of Earth are ozone, carbon dioxide, methane, and water vapour.
Carbon dioxide, methane, nitrous oxides, and water vapour are examples of greenhouse gases. (A "feedback" is the term used to describe water vapor, which reacts chemically or physically to changes in temperature.) Scientists have found that the warming effect of carbon dioxide contributes to the stabilisation of Earth's atmosphere.
Thus, the atmosphere of the Earth may begin to trap more and more heat if these greenhouse gases are present in excess. Earth warms as a result of this.
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How much heat is absorbed in the complete reaction of 3.00 grams of SiO2 with excess carbon in the reaction SiO2(g) + 3C(s) → SiC(s) + 2CO(g) ΔH° = 624.7 kJ/mol?
Answer:
31.24 kJ
Explanation:
SiO₂(g) + 3C(s) → SiC(s) + 2CO(g) ΔH° = 624.7 kJ/molFirst we convert 3.00 grams of SiO₂ to moles, using its molar mass:
3.00 g SiO₂ ÷ 60.08 g/mol = 0.05 molNow we calculate the heat absorbed, using the given ΔH°:
If the complete reaction of 1 mol of SiO₂ absorbs 624.7 kJ, then with 0.05 mol:
0.05 mol * 624.7 kJ/mol = 31.24 kJ of heat would be absorbed.The heat absorbed by 3.00 grams of SiO2 is 31.17 kJ/mol.
The thermochemical equation is;
SiO2(g) + 3C(s) → SiC(s) + 2CO(g) ΔH° = 624.7 kJ/mol
The number of moles of SiO2 = 3.00 g/60.08 g/mol = 0.0499 moles
From the reaction equation;
1 mole of SiO2 absorbs 624.7 kJ/mol
0.0499 moles SiO2 absorbs 0.0499 moles × 624.7 kJ/mol/1 mole
= 31.17 kJ/mol
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Do number 5 vote you brainlest thanks
Answer:
DNA
Explanation:
because genetics come from DNA
Question 4 of 20
A student is performing experiments on a particular substance. Which
statement is an observation of a chemical property of the substance?
A. Its viscosity decreases.
B. It boils.
C. Electricity passes through it.
D. It reacts with acid.
SUBMIT
Answer:
D
Explanation:
Reacting with acid is the only chemical property out of the 4 options. The rest are physical
Petroleum is a mixture of many alkanes. The alkanes are separated and purified at oil refineries. What process decribes what happens in an oil refinery?
Answer:
Fractional distillation
Explanation:
The process of separating petroleum products into its fractions is called fractional distillation.
Fractional distillation is a method of separating a mixture of substances based on the differences in their boiling points.
Petroleum is a mixture of hydrocarbons separated in a large fractionation tower having many trays maintained at different temperatures.
As the vapor containing the petroleum mixture ascends the fractionation tower, the mixture is separated at each tray to yield the various fractions of petroleum.
Thea is doing a chemistry experiment. The instructions say she needs to use pure water. Hamza offer her a bottle labelled “100% Pure Spring Water”. Suggest why this water is unlikely to be suitable for the experiment [2]
A scientist is comparing 2 samples of the same compound. One is pure and the other is impure. The compound is a solid at room temperature. Explain how the scientist could tell which is the pure compound. [2]
The melting point of pure asprin is 136oC. The melting point of a sample of asprin is measured as being between 128 – 132oC. Give two reasons that suggest the sample is not pure asprin. [2]
Gunpowder is a formulation of potassium nitrate, charcoal and sulphur in the ratio 15 : 3 : 2
What is meant by the term “formulation” [2]
Calculate the mass of charcoal in 40g of gunpowder [1]
if you can just give me hints that would be great
How many protons, electrons, and neutrons are in calcium?
Answer:
20 protons , 20 electrons and 20 neutrons
can someone please explain this i will give brainliest
why and how do ions form?
Answer and Explanation:
Ions are electrically charged particles that are formed from the removing and addition of electrons. It can be a positively or negatively charged atom.
What is the momentum of a car with a mass of 1,300 kg traveling north at a speed of 28 m/s?
Answer:
p = 36400 kg·m/s
Explanation:
p=mv
p= Momentum
m= mass (1300 kg)
v= 28
1300 × 28
= 36400 kg·m/s
The Momentum of the car is 36400 kg-m/s.
What is Momentum ?Momentum is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. m is an object's mass and v is its velocity
Given that,
Mass of the car, m = 1300 kgSpeed of the car, v = 28 m/s (towards north)(m is an object's mass and v is its velocity)
To find :
The momentum of car, p
Solve :
Let p is the momentum of an object. It can be calculated by the product of mass and its velocity. The formula to find it is given by :
p = m x v
= 1300 x 28
= 36400 kg-m/s.
Therefore, the momentum of the car is 36400 kg-m/s.
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If the available number of valence electrons for a molecule or polyatomic ion does not complete all of the octets in a lewis structure what should you do
Answer:
If the available number of valence electrons for a molecule or ion does not complete all of the octets, then multiple bonds must be drawn.
Explanation:
If the available number of valence electrons for a molecule or ion does not complete all of the octets, then multiple bonds must be drawn.
We must note that Lewis structures are representations of molecules Using dots to show the number of valence electrons on the valence shell of the atoms of each of the constituent elements in the molecule. Each atom is expected to have an octet of electrons on its outermost shell.
Many times, we encounter Lewis structures in which the octet of some atoms are incomplete. This means that the atoms have less than eight outermost electrons.
In such cases, we must invoke the idea of multiple bonds to account for the incomplete octet.
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in sublimation which state of matter is absent
sublimation is the transition of a substance directly from the solid to the state without passing through the liquid state
Why doesn't the Earth usually feel solar winds?
A. because of the aurora borealis
B. because of its strong magnetic field
C. because of strong magnetic activity inside the Sun
D. because they contain electromagnetic radiation
7. C2H4O2 is what? vinegar
Answer:
Yes its vinegar
Explanation:
Actually [tex] \bold{\red {C_2H_4O_2}} [/tex] is the formula for acetic acid which is found in vinegar.
What element has the following Electron Configuration?
If 276 g of dinitrogen tetroxide and 64.0 g of hydrazine are mixed, how many grams of nitrogen gas can you produce?
Answer:
84 g of N₂
Explanation:
We begin from the reaction:
N₂O₄ + 2N₂H₄ → 3N₂ + 4H₂O
1st step: Find out the limiting reactant.
We convert the mass to moles.
276 g . 1mol/ 92g = 3 moles of N₂O₄
64 g . 1mol / 32g = 2 moles of hidrazine
Limiting reactant is the hydrazine. Ratio is 1:2, then for 3 moles of tetroixde I may need 6 moles of N₂H₄. (But I only have 2).
To determine the grams of produced nitrogen we see stoichiometry (2:3)
2 moles of hydrazine can produce 3 moles of N₂
Definetaly our 2 moles make 3 moles of gas.
We convert the moles to mass.
3 mol . 28g /1mol = 84 g of N₂
Step 9: Measure Pressure and Volume with the Book and 4 kg of Weight Total the mass on the syringe. Record it in the correct row of the data table. kg
Answer:
498 g
0.498 kg
Explanation:
Answer:
4.498 kg
1.47
35.0
51.5
Explanation:
iron (ii) hydroxide + sodium nitrate. Name the precipitate formed in reaction
All elements in this series are radioactive
Answer:
you did not posted the series
Explanation:
What is the concentration of a solution containing 2.4 mol of NaCl dissolved in 3.0L of water?
Answer:
0.500 liters
Explanation:
Determina la densidad de una barra dd hierro cuya masa ed de 160gr y su volumen es de 20,35cm³ ¿que volumen ocuparan 12g de hierro?
Answer:
15.26 cm³
Explanation:
La densidad de una sustancia se define como su masa por unidad de volumen:
densidad = masa/volumen
Tenemos los siguientes datos de la barra de hierro:
masa = 160 g
volumen = 20,35 cm³
Por lo tanto, la densidad de la barra de hierro es:
densidad = 160 g/20,35 cm³ = 0.786 g/cm³
El volumen de 12 gramos de hierro se calcula utilizando el dato de masa (12 g) y la densidad calculada:
densidad = masa/volumen ⇒ volumen = masa/densidad
= 12 g/(0.786 g/cm³)
= 15.26 cm³
H2 + Cl2 --> 2HCl
If 500 molecules of H2 react with 400 molecules of Cl2, how many of HCl will be produced?
Answer:
c20 will be there ok
Explanation:
okbbbbbbbbbbyyyyyyyy
Select the correct answer.
When a substance changes from one phase to another, which of the following occurs?
OA. The substance loses or gains heat.
shoes
OB. The average kinetic energy of the substance changes.
OC. The temperature of the substance changes.
OD. The molecular motion of the substance changes.
Reset
Next
D. The molecular motion of the substance changes.
Please help! I will give brainliest.
Which group (family) of non-metals does not form ions?
Answer:
Noble gasses
Explanation:
nobled gasses
all elements want to loose or gain electrons to be like the noble gasses in bonding but the noble gasses do not bond.
How does the nervous system work with the digestive system?
A: The muscular and nervous systems enable the involuntary breathing mechanism.
B: It doesn't
C: The enteric nervous system's network of nerves, neurons and neurotransmitters extends along the entire digestive tract - from
the esophagus, through the stomach and intestines, and down to the anus.
D: Gets nutrients (good) from food and hands it over to the blood
Anyone help I’m failing :(
Answer:
Enteric Nervous System
The enteric nervous system (ENS) is a subdivision of the autonomic nervous system (ANS) that directly controls the gastrointestinal system.
LEARNING OBJECTIVES
Describe the structure and function of the enteric nervous system (ENS)
KEY TAKEAWAYS
Key Points
The enteric nervous system (ENS), which is embedded in the lining of the gastrointestinal system, can operate independently of the brain and the spinal cord.
The ENS consists of two plexuses, the submucosal and the myenteric. The myenteric plexus increases the tone of the gut and the velocity and intensity of contractions. The submucosal plexus is involved with local conditions and controls local secretion, absorption, and muscle movements.
While described as a second brain, the enteric nervous system normally communicates with the central nervous system (CNS) through the parasympathetic (via the vagus nerve ) and sympathetic (via the prevertebral ganglia) nervous systems, but can still function when the vagus nerve is severed.
The ENS includes efferent neurons, afferent neurons, and interneurons, all of which make the ENS capable of carrying reflexes and acting as an integrating center in the absence of CNS input.
The ENS contains support cells, which are similar to the astroglia of the brain, and a diffusion barrier around the capillaries surrounding the ganglia, which is similar to the blood –brain barrier of cerebral blood vessels.
Key Terms
enteric nervous system: A subdivision of the peripheral nervous system that directly controls the gastrointestinal system.
EXAMPLES
The second brain of the enteric nervous system is the reason we get butterflies in our stomach or need to use the restroom more frequently when we are nervous and/or under stress.
The gastrointestinal (GI) system has its own nervous system, the enteric nervous system (ENS). Neurogastroenterology is the study of the enteric nervous system, a subdivision of the autonomic nervous system (ANS) that directly controls the gastrointestinal system. The ENS is capable of autonomous functions such as the coordination of reflexes.
Although it receives considerable innervation from the autonomic nervous system, it can and does operate independently of the brain and the spinal cord. The ENS consists of some 100 million neurons, one-thousandth of the number of neurons in the brain, and about one-tenth the number of neurons in the spinal cord. The enteric nervous system is embedded in the lining of the gastrointestinal system.
Ganglia of the ENS
The neurons of the ENS are collected into two types of ganglia:
The myenteric (Auerbach’s) plexus, located between the inner and outer layers of the muscularis externa
The submucosal (Meissner’s) plexus, located in the submucosa
The Myenteric Plexus
The myenteric plexus is mainly organized as a longitudinal chains of neurons. When stimulated, this plexus increases the tone of the gut as well as the velocity and intensity of its contractions. This plexus is concerned with motility throughout the whole gut. Inhibition of the myenteric system helps to relax the sphincters —the muscular rings that control the flow of digested food or food waste.
The Submucosal Plexus
The submucosal plexus is more involved with local conditions and controls local secretion and absorption, as well as local muscle movements. The mucosa and epithelial tissue associated with the submucosal plexus have sensory nerve endings that feed signals to both layers of the enteric plexus. These tissues also send information back to the sympathetic pre-vertebral ganglia, the spinal cord, and the brain stem.
This is an illustration of neural control of the gut wall by the autonomic nervous system and the enteric nervous system. A sensory neuron is shown to stimulate the nerves in the submucosal and myenteric plexuses, which are connected to nerves in the sympathetic and parasympathetic nervous systems. The sensory neuron is also shown signal the ganglia and central nervous system.
Neural control of the gut: An illustration of neural control of the gut wall by the autonomic nervous system and the enteric nervous system.
Function and Structure of the ENS
The enteric nervous system has been described as a second brain. There are several reasons for this. For instance, the enteric nervous system can operate autonomously. It normally communicates with the central nervous system (CNS) through the parasympathetic (e.g., via the vagus nerve) and sympathetic (e.g., via the prevertebral ganglia) nervous systems. However, vertebrate studies show that when the vagus nerve is severed, the enteric nervous system continues to function.
Explanation:
how many atoms are in 1.2x10^5 moles of neon?
Answer:
7.224 × 10^28 atoms
Explanation:
The number of moles contained in a substance (n) can be calculated from this expression:
nA = n × 6.02 × 10^23 atoms
Where;
nA = number of atoms of substance
n = number of moles of substance
Avagadro's number or constant = 6.02 × 10^23 atoms
Using nA = n × 6.02 × 10^23 atoms
In this question, there are 1.2 x 10^5 moles of neon (N). The number of atoms (nA) is as follows:
nA of neon = 1.2 x 10^5 × 6.02 × 10^23
nA = 7.224 × 10^ (5 + 23)
nA = 7.224 × 10^28 atoms
The number of neon atoms in 1.2 x 10^5 is 7.224 × 10^28 atoms.