Answer:
Metalloids tend to be shiny like metals but brittle like nonmetals. Because they are brittle, they may chip like glass or crumble to a powder if struck. Other physical properties of metalloids are more variable, including their boiling and melting points, although all metalloids exist as solids at room temperature.
Explanation:
Which refrigerant is known to destroy ozone?
ammonia
Freon®
tetrafluoroethane
ice
Answer:
tetrafluoroethane
Explanation:
Its an HCFC, which are the refrigerants that destroy the ozone layer.
Answer:
Freon.
Explanation:
Brainliest plz???
The rolls in the table are called periods . which characteristic of the elements increases as you move across a period from left to right ?
Answer:
A. atomic number
Explanation:
An atomic number of the elements increases as you move across a period from left to right. Hence, option A is correct.
What is an atomic number?An atomic number is the number of a chemical element in the periodic system, whereby the elements are arranged in order of increasing the number of protons in the nucleus.
In a period atomic number increases as we move from left to right but the outermost shell remains the same. Hence it's only the number of protons increasing in the nucleus as we from left to right, the effect of the nucleus increases on the outermost shell hence atomic size decreases in a period.
Hence, The atomic number of the elements increases as you move across a period from left to right.
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When water particles in their gaseous state (X) lose enough energy, they
When water particles in their liquid state (Y) gain enough energy, they
Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Therefore, loosing and gaining energy by different phase of water, phases changes.
What is matter?Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.
Matter is anything that is made up of atoms. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.
When water particles in their gaseous state (X) lose enough energy, then the gaseous state of water converts to liquid state as the kinetic energy of particles decreases. When water particles in their liquid state (Y) gain enough energy, then water converts to vapor state.
Therefore, loosing and gaining energy by different phase of water, phases changes.
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The mass of an object is 240g and its volume is 60 cm3
A. Sink
B. Float
Answer:
A Sink
Explanation:
Anything greater than 1g/cm3 will sink in water
in a car engine a 250 mL cylinder and piston system is filled with a mixture of 0.42g and 0.24 g of octane gas and oxygen gas, respectively. Both gases are at room temperature of 33 c. If the total gas mixture is compressed to a pressure of 3.7 atm before combustion, calculate the total volume of gas mixture at this point in time.
Answer:
[tex]V_2=76.0mL[/tex]
Explanation:
Hello.
In this case, given the initial masses of both octane (C8H18, molar mass = 114 g/mol)) and oxygen (O2, molar mass = 32 g/mol), we can compute their moles and subsequently the total pressure via the ideal gas equation at 33 °C into the 250-mL:
[tex]n_{octane}=0.42g*\frac{1mol}{114g} =3.7x10^{-3}mol\\\\n_{oxygen}=0.24g*\frac{1mol}{32g} =7.5x10^{-3}mol\\\\n_T=7.5x10^{-3}mol+3.7x10^{-3}mol=0.0112mol\\\\P_1=\frac{n_TRT}{V_1}=\frac{0.0112mol*0.082\frac{atm*L}{mol*K}*(33+273.15)K}{0.25L}=1.1atm[/tex]
After that, via the Boyle's law, we compute the final pressure in the cylinder and piston system:
[tex]P_1V_1=P_2V_2\\\\V_2=\frac{P_1V_1}{P_2} =\frac{250mL*1.1atm}{3.7atm}\\ \\V_2=76.0mL[/tex]
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The unknown ionic compound gave a green flame test, precipitate with ammonium carbonate, and a colorless/light yellow halide test. What is the unknown compound?
Answer:
BaI2
Explanation:
Barium gives a green flame test. When the halide test is conducted, a yellow precipitate indicates the presence of the iodide ion.
Also, BaI2 reacts with ammonium carbonate as shown below:
BaI2(aq) + (NH4)2CO3(aq) → BaCO3(s) + 2(NH4)I(aq)
The BaCO3(s) separates from the reaction system as a precipitate.
QUESTION 6
1. What is the maximum amount (in grams) of sulfur dioxide that can be produced by the reaction of 1380 g
of dihydrogen sulfide with 6890 g of oxygen according to the balanced equation below?
2 H2S(g) + 3 O2(g) + 2 H2O(g) + 2 SO2(g)
Enter the numeric value in the box without units.
Answer:
Explanation:
2 H₂S(g) + 3O₂(g) = 2 H₂O(g) + 2SO₂(g)
2 moles 3 moles 2 moles
1380 g of H₂S = 1380 / 34 = 40.588 moles of H₂S
6890 g of oxygen = 6890 / 32 = 215.31 moles of oxygen
Here H₂S is limiting reagent .
2 mole of H₂S reacts to give 2 moles of sulfur dioxide .
40.588 moles of H₂S will react to give 40.588 moles of sulfur dioxide.
sulfur dioxide formed = 40.588 moles
= 40.588 x 64 = 2597.63 g of sulfur dioxide.
The maximum amount of sulfur dioxide is 2597.63 g of sulfur dioxide.
Calculation of maximum amount:Since
2 H₂S(g) + 3O₂(g) = 2 H₂O(g) + 2SO₂(g)
So,
2 moles 3 moles 2 moles
Now
= 1380 g of H₂S
= 1380 / 34
= 40.588 moles of H₂S
Now
= 6890 g of oxygen
= 6890 / 32
= 215.31 moles of oxygen
Here H₂S represents limiting reagent .
2 moles of H₂S reacts to provide 2 moles of sulfur dioxide .
Now
40.588 moles of H₂S will react to provide 40.588 moles of sulfur dioxide.
Also,
sulfur dioxide formed = 40.588 moles
So,
= 40.588 x 64
= 2597.63 g of sulfur dioxide.
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Which of the following molecules would contain a polar covalent bond? A molecule containing two atoms
Answer:
of different elements with different electronegativities
Explanation:
A molecule containing two atoms "of different elements with different electronegativities"
A polar covalent bond exists when two different atoms (non-metals) with different electronegativities are able to share their electrons in a covalent bond.
Some examples of polar covalent bonds are seen in:
1. Ammonia(NH3): The polar covalent bonds exists between the nitrogen and hydrogen atoms.
2. Water(H2O): The polar covalent bond exists between hydrogen and oxygen. The oxygen molecule has a net negative charge while the hydrogen atoms have a net positive charge.
The molecular formula of butane is C4H10. It is obtained from petroleum and is used commonly in LPG (Liquefied Petroleum Gas) cylinders (a common source of cooking gas). It has two arrangements of carbon atoms: a straight chain and a branched chain. Using this information, draw the structure of the tertiary butyl radical that will form upon removal of a hydrogen atom. Draw the molecule on the canvas by choosing buttons from the Tools (for bonds).
Answer:
See attached picture.
Explanation:
Hello.
In this case, since butane has two common occurring structures, n-butane and isobutane, there is a way in which the tert-butyl radical can be formed upon the removal of a hydrogen from the isobutane form of butane as shown on the attached picture, wherein you can see that the radical is named by "tert" since the central carbon is bonded to three carbon atoms, that is why we classify it as tertiary. Moreover, it is a radical due to the presence of the bolded dot next to the tertiary carbon suggesting that it is very likely to bond with an other atom.
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7. The data that Carrie collected is classified as ___ data.
A. Quantitative
B. Qualitative
C. Neither
D. Both
The answer is A) Quantitative because Carrie has collected actual data and has not just made a judgement or prediction.
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Identify each process numbered 1-6
Answer:
1 = Melting
2 = Freezing
3 = Sublimation
4 = Deposition
5 = Condensation
6 = Boiling
Explanation:
When a base metal is converted into gold - this phenomenon is best described as what?
Answer:
Alchemy
Explanation:
Alchemy is the believe that base metals such as a copper, lead etc can be transmuted into gold.
The alchemists were in search of a magical piece that would enable them to make gold from base metals. They called this magical stuff 'the Philosopher's Stone'.
Modern science has discovered that lead can be turned into gold,without applying the methods of alchemy. Nuclear transmutation in particle accelerators can indeed change one element into another.
Na3AsO4 is a salt of a weak base that can accept more than one proton. If 18.4 g of Na3AsO4 is dissolved in water to make 250mL of solutions how many moles of sodium cations are in the solution?
Answer in units of mol.
Answer:
0.266 moles of Na⁺
Explanation:
First step we dissociate the salt:
Na₃AsO₄ → 3Na⁺ + AsO₄⁻³
From 1 mol of sodium arsenate, we must have 3 moles of sodium cation and 1 mol of arsenate.
We determine the moles of salt:
18.4 g . 1 mol/ 207.89 g = 0.0885 moles of salt.
We apply the followring rule of three:
1 mol of salt has 3 moles of Na⁺
0.0885 moles of salt may have (0.0885 . 3) / 1 = 0.266 moles of Na⁺
3
Identify the ions present in K2HPO4.
1) K+ and H+ and PO43-
6
2) K 2+ H+, and PO43-
9
3) K+, H+, p3-, and O2-
4) K2H3+ and PO43-
5) K2HPO4 is not ionic.
Answer:
K⁺ and HPO₄²⁻ ions are present in K₂HPO₄
Explanation:
K₂HPO₄ consist of anion and cation such as HPO₄²⁻ and K⁺. We can see that the charge on HPO₄²⁻ is negative 2. Thus inroder to balance the charge and to neutral the compound two potassium ions are attached because the charge on one atom of potassium is K⁺.
Properties of K₂HPO₄ :
It is salt of phosphoric acid.
Its density is 2.44 g/cm³.
It is odourless compound.
It is white powder and soluble in water.
It is used in fertilizer because it provide phosphorus which is beneficial for the growth of plants.
It is also used as a additive in food.
It is inorganic compound and also used as buffering agent.
You are assigned the task of separating a desired granular material, with a density of 3.26 g/cm3, from an undesired granular material that has a density of 2.04 g/cm3. You want to do this by shaking the mixture in a liquid. A solid will float on any liquid that is more dense. Using an Internet-based source, find the densities of the following substances: carbon tetrachl oride, hexane, benzene, and diiodomethane. Which of these liquids will serve your purpose, assuming no chemical interaction between the liquid and the solids?
Answer:
diiodomethane
Explanation:
The densities of each of the liquids mentioned in the question are stated below;
CCl4- 1.59 g/cm^3
Hexane- 0.672 g/cm^3
Benzene- 0.8765 g/cm^3
Diiodomethane- 3.3 g/cm^3
Clearly, the density of diiodomethane methane is almost the same as that of the desired granular material, hence the undesired granular material having a density of 2.04 g/cm3 will float in diiodomethane thus separating the two granular materials.
What do tissues combine to form?
A.organisms
B.organs
C.organ systems
D.cells
Answer:
b. organs
Explanation:
molecules combine to form cells, cells combine to form tissues, tissues combine to form organs, organs combine to form organ systems, and organ systems combine to form organisms.
Answer:
B. Organs
Explanation:
Cell - Tissue - Organs - Organ Systems - Organism
15. Glucose reacts with oxygen to give CO2 and H20. What mass of oxygen (in grams) is required for
complete reaction of 25.0 g of glucose?
a. 25.0 g
b. 0.83 g
c. 26.6 g
d. 30.1 g
if the atomic number of Potassium is 19 and its mass is 39 what will be the number of electrons protons and neutrons and atoms also give its symbol and sure its electronic configuration pictorially
Answer:
Explanation:
Symbol: K
Protons = 19
Electrons in an atom: 19
Neutrons: 39 - 19 = 20
Draw the nucleus at the center. Label it with 19 Protons and 20 Neutrons.
Draw a circle around the nucleus.
Put two dots opposite each other on the circle's circumference.
Draw another circle with its center at the nucleus bigger than you first circle.
Space 8 electrons around the circumference.
Draw a third circle like the other 2 only bigger.
Space 8 electrons around this circle's circumference.
Draw 1 more circle bigger than the third circle.
It has 1 electron.
This is timed i need this fast
Answer:
1. or A
Explanation:
What is the answer A,B,C,D?
Answer:
Explanation:
I think that it is frequency
Answer:
B
Explanation:
is the solid planet itself.
Which scientist was the first to practice the scientific method we use today
En Hedu'Anna
Aristotle
Archimedes
Answer:
Aristotle
Explanation:
Answer: Aristotle
Explanation:
because i took the quiz
11. Drawing the Graph
Mass vs Volume
SER
20
15
10
2
4
Nu
12. Find the slope of the line (density of the substance);
Questions and Problems
Q1A metal object has a mass of 8 37 2. When it was placed in a graduated cylinder
containing 20.0 ml. of water, the water level rose to 23.1 mul
a) What is the density of the metal (Show calculation?
a) What is the identity of the metal (see Reference Table S)
Q2What is the mass of a solution that has a density of 0 775 gm. and a volume of
500 ml?
Q3What is the volume of a solution that has a density of 12 g ml, and mass of 185?
No
Explain in a paragraph how do you know or can find the number of each subatomic particle using the information on the periodic table. include why the atomic mass of your element on the periodic table is not a whole number or why it is. (PLEASE ANSWER FOR BRAINLEST ANSWER)
Answer:
A typical atom consists of three subatomic particles: protons, neutrons, and electrons (as seen in the helium atom below). Other particles exist as well, such as alpha and beta particles (which are discussed below). The Bohr model shows the three basic subatomic particles in a simple manner. Most of an atom's mass is in the nucleus—a small, dense area at the center of every atom, composed of nucleons. Nucleons include protons and neutrons. All the positive charge of an atom is contained in the nucleus, and originates from the protons. Neutrons are neutrally-charged. Electrons, which are negatively-charged, are located outside of the nucleus.
Explanation:
What is the name of the unit in the measurement 0.8 L
Answer:
hiiiiiiiiiiiiiiiiiiiiiiiiiiii
Answer:
The name of this unit in the measurement is called: Liter
Calculate the hydronium ion, H3O+ , and hydroxide ion, OH− , concentrations for a 0.0440 M HCl solution. [H3O+]= M [OH−]=
Answer:
[H3O+] = 0.0440M
[OH-] = 2.27x10⁻¹³M
Explanation:
Based on the equilibrium of water:
2H2O ⇄ H3O+ + OH-
K = 1x10⁻¹⁴ = [H3O+] [OH-] (1)
We can determine [OH-] with [H3O+] or vice versa
As HCl is a strong acid, [HCl] = [H3O+]
That means:
[H3O+] = 0.0440M
And [OH-] is:
1x10⁻¹⁴ / [H3O+] = [OH-]
2.27x10⁻¹³M = [OH-]
Taking into account the definition of pH and pOH, the hydronium ion, H₃O⁺, and hydroxide ion, OH−, are 0.044 M and 2.29×10⁻¹³ M respectively.
First of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:
pH= - log [H⁺]= - log [H₃O⁺]
Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
The following relationship can be established between pH and pOH:
pOH + pH= 14
In this case, you have a 0.044 M HCl. HCl is a strong acid.
It is called strong acid, that acid that dissociates completely in solution at constant temperature and pressure. Under these conditions, the concentration of a strong acid is equal to the concentration of hydrogen ions (Hydronium or H₃O⁺). Then, in this case:
[H⁺]= [H₃O⁺]= [HCl]= 0.044 M
Replacing in the definition of pH:
pH= -log (0.044 M)
Solving:
pH= 1.36
Considering the relationship established between pH and pOH:
pOH + 1.36= 14
pOH= 14 -1.36
pOH= 12.64
Finally, replacing in the definition of pOH:
12.64= -log [OH-]
[OH-]= 10⁻¹² ⁶⁴
[OH-]= 2.29×10⁻¹³ M
In summary, the hydronium ion, H₃O⁺, and hydroxide ion, OH−, are 0.044 M and 2.29×10⁻¹³ M respectively.
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brainly.com/question/12200689 brainly.com/question/16032912?referrer=searchResults brainly.com/question/13557815?referrer=searchResultsI need ASAP! When particles are enclosed in a vesicle and released OUT of a cell, the process is called:
A
Osmosis
B
Diffusion
C
Endocytosis
D
Exocytosis
Answer:D Diffusion
Explanation:
Because the the cell Is letting it go diffuse it to remove it.
Which of the following characteristics of the pineal gland is not correct? A. The pineal gland is located in the brain, above the cerebellum. B. The pineal gland acts as an internal clock. C. The pineal gland regulates sleep and waking cycles. D. The pineal gland regulates salt and water levels.
Answer:
D
Explanation:
The pineal gland regulates salt and water levels.
The pineal gland does not regulate salt and water levels. Therefore, option (D) is correct.
What is the pineal gland?The pineal gland can be described as a pinecone-shaped small gland located in the middle of the human brain. The pineal gland is the main site for melatonin secretion, which regulates the internal clock of the body.
The dimensions of the pineal gland can be described as about 0.3 inches long and weighing 0.1 grams. The pineal gland is made of pinealocytes and supporting cells that are similar to the astrocytes in the brain.
The pineal gland secretes the hormone melatonin and this hormone regulates the circadian rhythm of the body and also reproductive hormones. The secretion of hormones depends upon the quantity of light a person is exposed to.
This hormone is formed in huge amounts when it is dark. The presence of light prevents the secretion of melatonin which controls circadian rhythms.
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Magnesium can interfere with the measurement of the calcium concentration in water samples using colorimetric tests. Write a balanced chemical equation for the reaction of dissolved magnesium chloride with sodium hydroxide to form magnesium hydroxide as a precipitate and sodium chloride.
(Reactants -> Products)
Answer:
[tex]MgCl_2+2NaOH\rightarrow 2NaCl+Mg(OH)_2[/tex]
Explanation:
Hello.
In this case, since aqueous magnesium chloride reacts with aqueous sodium hydroxide, a precipitate product, magnesium hydroxide is formed as well as aqueous sodium chloride as shown below:
[tex]MgCl_2+NaOH\rightarrow NaCl+Mg(OH)_2[/tex]
However, since there are two chlorine atoms at the reactants we need a 2 before NaCl on the products in order to balance it. Moreover, there one OH at the reactants and two OH at the products, that is why we also add a 2 before NaCl as shown below:
[tex]MgCl_2+2NaOH\rightarrow 2NaCl+Mg(OH)_2[/tex]
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Q1) A vapor-compression refrigeration system operates on the cycle of Fig. 9.1. The refrigerant is 1,1,1,2-Tetrafluoroethane. Given that the evaporation T = 4°C, the condensation T = 34°C, η(compressor) = 0.76, and the refrigeration rate = 1200 kJ⋅s−1, determine the circulation rate of the refrigerant, the heat-transfer rate in the condenser, the power requirement, the coefficient of performance of the cycle, and the coefficient of performance of a Carnot refrigeration cycle operating
between the same temperature levels.
Answer:
i) 0.5071 (kg/s)
ii) -1407.1 kj/kg
iii) 204.05 Kw
iv) 5.881
v) 9.238
Explanation:
Given Data:
evaporation temperature ( T ) = 4°c = 277.15 K
Condensation Temperature ( T ) = 34°c = 307.15 K
n ( compressor efficiency ) = 0.76
refrigeration rate = 1200 kJ.s^-1
i) determine the circulation rate of the refrigerant
m = [tex]\frac{Q}{H2 - H1}[/tex] = [tex]\frac{Q}{H2 - H4\\}[/tex] ------- 1
Q = 1200 Kj.s^-1
H2 = entropy at step 2 = 2508.9 (kJ / kg ) ( gotten from Table F )
H4 = entropy at step 4 = 142.4 ( kJ/ kg )
back to equation 1
m ( circulation rate of refrigerant ) = 0.5071 (kg/s)
ii) heat transfer rate in the condenser
Q = m ( H4 - H3 )
= 0.5071 ( 142.4 - 2911.27 )
= -1407.1 kj/kg
where H3 = H2 + ΔH23 = 2911.27 (kj/kg) ( as calculated )
iii) power requirement
w = m * ΔH23
= 0.5071 (kg/s) * 402.37 (kj/kg) = 204.05 Kw
where: ΔH23 = [tex]\frac{H'3 - H2 }{0.76}[/tex] = [tex]\frac{2814.7-2508.9}{0.76}[/tex] = 402.37 (kj/kg)
iv) coefficient of performance of a cycle
W = Qc / w
= 1200 Kj.s^-1/ 204.05 kw
= 5.881
v) coefficient of performance of a Carnot refrigeration cycle
[tex]w_{carnot} = \frac{T2}{T4 - T2}[/tex]
= 277.15 / ( 307.15 - 277.15 )
= 9.238