Answer:
The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).
Explanation:
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Which is the best description of a molecule?
A molecule of an element is composed of at least two types of atoms.
A molecule of a compound is composed of only one type of atom.
A molecule of a compound is composed of at least two types of atoms.
A molecule of an element is composed of exactly two types of atoms.
Answer:
The third option "A molecule of a compound is composed of at least two types of atoms" is correct
Explanation:
This question isn't about molecules, it's about elements and compounds.
Elements are made of one and only one type of atoms, while compounds are made of more than one type of atoms.
(Molecules are just groups of atoms, it doesn't matter what they're made of)
Answer:
a
Explanation:
Which of these is an example of a description of
speed?
An airplane traveled west from New York to Los
Angeles.
A train traveled east at 200 mph from Albuquerque to
Dallas.
The average Olympic sprinter runs 8 m/s.
An apple fell from the tree and then rolled 1 m north.
Answer:
The average Olympic sprinter runs 8 m/s.
Explanation:
Speed is defined as the change of an object from one position to another position with respect to the time taken. It is independent of direction and only depends on the change of its position.
In the context, all the other sentences has direction mentioned in the sentence except the sentence "the average Olympic sprinter runs 8 m/s". In this sentence, the speed of an Olympic sprinter id given i.e. 8 meter per second.
a 12m tall electric pole is supported by a wire from top making an angle 60 with pole.what is lenght of pole?
Answer:
i think 70inches
Explanation:
In an atom how many protons and electrons
Answer:
Atoms must have equal numbers of protons and electrons. In our example, an atom of krypton must contain 36 electrons since it contains 36 protons.
Explanation:
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effects of mg2 on enhancing luminescence efficiency for a red long persistent phosphor γ-zn3 (po4) 2: mn2
Through homogeneous co-precipitation and traditional solid-state calcining, a red long persistent phosphor of -Zn3(PO4)2: Mn2+, Mg2+ was created.
Effects of mg2 on improving luminous performance for a red long-lasting phosphor, -zn3 (po4) 2: mn2X-ray diffractions, scanning electron microscopes, X-ray photoelectron spectroscopies, decay curves, and thermoluminescence spectra were used to corroborate the crystalline structures and characteristics of the materials. The phase transition of Zn3(PO4)2:Mn2+ from to as well as the enhancement of the crystallinity of phosphors will be caused by the dopant of Mg2+, according to the XRD results. A noticeable peak at 620 nm in the photoluminescence emission spectrum of the red -Zn3(PO4)2: Mn2+, Mg2+ phosphor is due to the Mn2+ ion's 4T1g-6A1g transition. The addition of Mg2+ as a dopant can significantly improve the luminous characteristics of -Zn3(PO4)2: Mn2+. For the discussion of intrinsic flaws, TL curves are used. The suggested persistent luminescence operating mechanismlearn more about phosphor here
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what element is a F-18 Atom
Answer:
Sodium Fluoride F 18 Injection is a positron emitting radiopharmaceutical, no-carrier added.
Explanation:
Element Name Fluorine
Element Symbol F
Atomic Number 9
Weathering and erosion are the same thing. true or false? i personally think its false but just to be sure lol
Answer:
It is false.
Explanation:
Weathering is the general process by which rocks are broken down at Earth's surface. Erosion is a set of processes that loosen and move soil and rock downhill or downwind. Umm...for example, imagine you are having ice cream in your hand out on a sunny day, if the ice-cream melts and falls down, it is called erosion and if the ice-cream melts but it doesn't fall down, it called weathering.
Calculate the molar mass of a gas with a mass of 3.15 g, a pressure of 785 mmHg, and a temperature of 20 Celsius. The gas has a volume of 750 ml.
Answer:
Molar mass = 105 g/mol
Explanation:
Given data:
Mass of gas = 3.15 g
Pressure = 785 mmHg
Temperature = 20°C
Volume of gas = 750 mL
Molar mass of gas = ?
Solution:
Pressure = 785 mmHg (785/760 = 1 atm)
Temperature = 20°C (20+273 = 293 K)
Volume of gas = 750 mL (750 mL× 1 L/1000 mL = 0.75 L)
PV = nRT
R = general gas constant (0.0821 atm.L/mol.K)
1 atm× 0.75 L = n×0.0821 atm.L/mol.K × 293 K)
0.75 atm.L = n× 24.06 atm.L/mol
n = 0.75 atm.L / 24.06 atm.L/mol
n = 0.03 mol
Molar mass of gas:
Molar mass = Mass / number of moles
Molar mass = 3.15 g/ 0.03 mol
Molar mass = 105 g/mol
How does heat transfer by radiation different from the heat transfer by conduction or convection
The major difference between heat transfer by conduction and convection and heat transfer by radiation is that heat transfer by conduction and radiation requires a material medium, while heat transfer by radiation is done by electromagnetic waves and doesn't require a medium.
Heat or thermal energy is the energy generated when atoms or molecules move in a variety of directions (translational, rotational and vibrational). The three methods of heat transfer are convection, conduction and radiation. Conduction only occurs between solid objects in contact, convection occurs within a fluid, and radiation occurs through electromagnetic waves.
Unlike conduction and convection, radiation doesn't require a material medium before heat is transferred, as electromagnetic radiations don't require a material medium to propagate. Heat is transferred by radiation through infrared rays. Other differences include:
Conduction and convection are slow, while radiation is fast, as infrared rays travel at the speed of light.Radiation can be reflected using mirrors, while conduction and convection cannot.Learn more about radiation here:
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how many molecules are in 9.45 moles ? ( NaNO3)
Answer:
There are 5.69*10²⁴ molecules in 9.45 moles.
Explanation:
The mole is defined as the amount of matter that particles have, that is, atoms and elementary entities.
Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole and represents a quantity without an associated physical dimension. Avogadro's number applies to any substance.
Then the following rule of three can be applied: if 1 mole contains 6.023 * 10²³ molecules, 9.45 moles, how many molecules will it have?
[tex]amount of molecules=\frac{9.45 moles*6.023*10^{23}molecules }{1 mole}[/tex]
Solving:
amount of molecules= 5.69*10²⁴⁴ molecules
There are 5.69*10²⁴ molecules in 9.45 moles.
what is a coefficient
Answer:
In mathematics, a coefficient is a multiplicative factor in some term of a polynomial, a series, or any expression; it is usually a number, but may be any expression. In the latter case, the variables appearing in the coefficients are often called parameters, and must be clearly distinguished from the other variables.
Explanation:
MULTIPLE CHOICE
True or False: Any metal object that contains iron,
such as steel, will be attracted to a magnet.
Answer:
TRUE
Explanation:
is adrenaline radioactive?
Answer:
Yes adrenaline is radioactive.
Explanation:
ionic compounds are electrically neutral overall. therefore, the sum of the charges on the cation and anion in each formula unit must be equal to .
ionic compounds are electrically neutral overall. therefore, the sum of the charges on the cation and anion in each formula unit must be equal to zero
What is ionic compound ?Ions are charged particles that form when an atom (or group of atoms) receives or loses an electron, and ionic compounds are composed of these charged particles. An anion is a negatively charged ion, whereas a cation is a positively charged ion.
The simplest way to determine whether a chemical compound is an ionic compound is to see if it only contains two elements, one of which can be a metal (belonging to either of groups 1, 2, or 3), and the other of which can be a non-metal (from group 5, 6 or 7).Learn more about Ionic Compound here:
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A force that opposes or has resistance to motion.
use the internet to look up the sds for 2.0 m sodium hydroxide naoh to answer the following question a) list the potential acute
A safety data sheet is informational data that states the properties of the various chemicals. According to the SDS of NaOH, it causes irritation, nausea, eye burn, burns in the digestive system, etc.
What is SDS?SDS is abbreviated for a safety data sheet which is a document that provides information on the chemicals including the properties, health hazards, measures, safety, prevention, etc.
According to SDS, NaOH results in various potential acute health effects including vomiting, diarrhea, nausea, irritation, etc. The chronic effect includes coma, burns in the eye, respiratory infection, digestive system, dermatitis, etc.
Therefore, sodium hydroxide has various acute and chronic health effects.
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Your question is incomplete, but most probably your full question was, Use the internet to look up the sds for 2.0 m sodium hydroxide, NaOH, to answer the following question: list the potential acute and chronic health effects.
Double-Replacement Reactions
LiCl + CaBr2 →
Cr(OH)3 + Na2CO3 →
Sr3N2 + KClO3 →
Fe(NO3)2 + AlPO4 →
CuSO4 + AgNO3 →
HCl + Ba(OH)2 →
CsCN + SnF4 →
(NH4)2S + Mg(NO3)2 →
Na2CrO4 + Mo(OH)3 →
Ni(C2H3O2)2 + H3PO4 →
Answer:
(1) LiCl + CaBr2 → CaCl2 + LiBr
Balanced
2LiCl + CaBr2 → CaCl2 + 2LiBr
(2) Cr(OH)3 + Na2CO3 → NaOH + Cr2(CO3)3
Balanced
2Cr(OH)3 + 3Na2CO3 → 6NaOH + Cr2(CO3)3
(3) Sr3N2 + KClO3 → Sr(ClO3)2 + K3N
Balanced
Sr3N2 + 6KClO3 → 3Sr(ClO3)2 + 2K3N
(4) Fe(NO3)2 + AlPO4 → Fe3(PO4)2 + Al(NO3)3
Balanced
3Fe(NO3)2 + 2AlPO4 → Fe3(PO4)2 + 2Al(NO3)3
(5) CuSO4 + AgNO3 → Ag2SO4 + Cu(NO3)2
Balanced
CuSO4 + 2AgNO3 → Ag2SO4 + Cu(NO3)2
(6) HCl + Ba(OH)2 → H2O + BaCl2
Balanced
2HCl + Ba(OH)2 → 2H2O + BaCl2
(7) CsCN + SnF4 → CsF + Sn(CN)4
Balanced
4CsCN + SnF4 → 4CsF + Sn(CN)4
(8) (NH4)2S + Mg(NO3)2 → MgS + NH4NO3
Balanced
(NH4)2S + Mg(NO3)2 → MgS + 2NH4NO3
(9) Na2CrO4 + Mo(OH)3 → NaOH + Mo2(CrO4)3
Balanced
3Na2CrO4 + 2Mo(OH)3 → 6NaOH + Mo2(CrO4)3
(10) Ni(C2H3O2)2 + H3PO4 → Ni3(PO4)2 + C2H4O2
Balanced
3Ni(C2H3O2)2 + 2H3PO4 → Ni3(PO4)2 + 6C2H4O2
When 7.68 g of zinc react with hydrochloric acid, what volume of hydrogen gas will be collected at 20.00C and 740 mm Hg?
Answer:
V ≈ 2.9 L H₂
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisChemistry - Reactions
Aqueous Solutions and states of matterReaction PredictionChemistry - Gas Laws
Combined Gas Law: PV = nRT
P is pressureV is volume in litersn is amount of moles of substanceR is a constant - 62.4 (L · mmHg)/(mol · K)T is temperature in KelvinsTemperature Conversion: K = °C + 273.15
Explanation:
Step 1: Define
Unbalanced RxN: Zn (s) + HCl (aq) → ZnCl₂ (aq) + H₂ (g)
Balanced RxN: Zn (s) + 2HCl (aq) → ZnCl₂ (aq) + H₂ (g)
Given: 7.68 g Zn, 20.00 °C, 740 mmHg
Step 2: Identify Conversions
Kelvin Conversion
Molar Mass of Zn - 65.39 g/mol
Step 3: Convert
Stoichiometry: [tex]7.68 \ g \ Zn(\frac{1 \ mol \ Zn}{65.39 \ g \ Zn} )(\frac{1 \ mol \ H_2}{1 \ mol \ Zn} )[/tex] = 0.117449 mol H₂
Temp Conversion: 20.00 + 273.15 = 293.15 K
Step 4: Find V
Substitute: (740 mmHg)V = (0.117449 mol)(62.4 (L · mmHg)/(mol · K))(293.15 K)Multiply: (740 mmHg)V = 2148.45 L · mmHgIsolate V: V = 2.9033 L H₂Step 5: Check
We are given 2 sig figs as our lowest. Follow sig fig rules and round.
2.9033 L H₂ ≈ 2.9 L H₂
A substance dissolved in a liquid is a
solution
evaporation
vein
geode
What are the similarities and differences between ionic compounds and metals? Why are they important? Describe some common ionic compounds and metals and their uses in everyday life.
Answer:
Similarities:
1. Electrostatic attraction between particles of unlike charges. occurs in both ionic compounds and metals
2. Both involve metallic cations. Metallic cations are present in both ionic compounds and in metals.
3. Both ionic compounds and metals have a crystal lattice structure in their solid state.
4. Both ionic compounds and metals have high melting and boiling points
5. Both can conduct electricity although ionic compound do so only in molten or solution form.
Differences:
1. The crystal lattice of an ionic compound consists of two oppositely charged ions of two or more elements whereas metals lattices consists of metal cations and delocalised electrons of the same metal.
2. Ionic compounds are compounds whereas metals are elements.
3. Ionic compounds are brittle whereas metals are malleable and ductile.
4. Electrons are transferred from one atom to another in ionic compounds whereas in metals, are delocalised around metallic cations
5. Metals are sonorous and are shiny whereas ionic compounds are not.
Importance of ionic compounds and metals
Ionic compounds are important as salts in industries, as food additives, in detergent and soap-making, as electrolytes and in biochemical systems.
Metals are important in building and construction industry, in jewellery, as conductors in wires and electrode plates, in making parts for vehicles used in transportation
Common ionic compounds and their uses:
Sodium chloride, Potassium iodide and Sodium fluoride are used as a food additive and preservative, as electrolytes, as well as in toothpastes for healthy teeth.
Common metals and their uses
Iron, Aluminum and Gold are used in steel production, making many cooking utensils and for making jewelleries
Explanation:
Similarities:
1. Electrostatic attraction between particles of unlike charges. occurs in both ionic compounds and metals
2. Both involve metallic cations. Metallic cations are present in both ionic compounds and in metals.
3. Both ionic compounds and metals have a crystal lattice structure in their solid state.
4. Both ionic compounds and metals have high melting and boiling points
5. Both can conduct electricity although ionic compound do so only in molten or solution form.
Differences:
1. The crystal lattice of an ionic compound consists of two oppositely charged ions of two or more elements whereas metals lattices consists of metal cations and delocalised electrons of the same metal.
2. Ionic compounds are compounds whereas metals are elements.
3. Ionic compounds are brittle whereas metals are malleable and ductile.
4. Electrons are transferred from one atom to another in ionic compounds whereas in metals, are delocalised around metallic cations
5. Metals are sonorous and are shiny whereas ionic compounds are not.
Importance of ionic compounds and metals
Ionic compounds are important as salts in industries, as food additives, in detergent and soap-making, as electrolytes and in biochemical systems.
Metals are important in building and construction industry, in jewellery, as conductors in wires and electrode plates, in making parts for vehicles used in transportation
Common ionic compounds and their uses:
Sodium chloride: sodium chloride is an ionic compound composed of sodium and chloride ions. It is commonly used as a food additive and preservative, as an electrolyte, as well as the extraction of sodium metal.
Potassium iodide: it is composed of potassium and iodine ions. It is added to “iodized” salt to prevent goitre.
Sodium fluoride: it consists of sodium and fluoride ions. It is an important ingredient in toothpaste for healthy teeth.
Common metals and their uses
Iron; iron is used in steel production which is used for constructing bridges, houses, and various machinery parts
Aluminum: it is used in making many cooking utensils like pots and pans
Gold: it is used in making jewelleries and ornaments.
Iconic bonds only form with metals and non metals. They have to give up electrons and non metals want to gain electrons.
They are important as the variance electrons are transfer from the meal to the neighboring nonmetal. But the electron bonding they are free to float around within the entire solid metal. Sodium carbonate, potassium chloride an magnesium sulphate etc. are some of the common iconic compounds.Learn more about the and differences between ionic compounds.
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Calculate the maximum wavelength of light capable of dissociating the f–f bond in one molecule of fluorine if the bond energy, or bond dissociation energy, is 157 kj/mol.
Maximum wavelength of light capable of dissociating the f-f bond is 7.6245 nm.
How is wavelength related to dissociation energy calculated?Wavelength related to bond dissociation energy is calculated by first calculating the energy required to break one f-f bond which is calculated as,
energy required to break a bond=bond energy/Avogadro's number
In this case which is equal to,157×10³/6.022×10²³=2.6071×10[tex]^-19[/tex] J.
Now to calculate wavelength, Planck's equation is used which is,
E=hc/λ
∴λ=6.626×10[tex]^-34[/tex]×3×10⁸/2.6071×10[tex]^-19[/tex]
=7.6245×10[tex]^-7[/tex] m or 7.6245 nm
Thus, the maximum wavelength of light capable of dissociating the f-f bond in one molecule of fluorine is 7.6245 nm.
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Which chemicals are reactants?
0: NH₃ + 0 02
0:02 0: N2 + 0:420
A. NH3 and O2
B. O, and H2O
C. N, and H2O
D. NH3 and N2
Light radiation travels as a wave and does ________ require a _____________ for travel
Answer:
not
medium
Explanation:
Light radiation travels as a wave and does not require a medium for travel. Like all electromagnetic radiations, light does not need medium particles for its propagation.
Light radiation can pass through a vacuum of space without particles. This carries energy from one point to another in this region of space. Such form of waves are electromagnetic waves. Electromagnetic waves can be propagated through vacuums.What is the name of CF7
Answer:
Formula mass in daltons of the chemical component.
The electrostatic potential of atoms in a molecule is not a visual representation of the atom's potential to attract or repel a
A.) electron
B.) neutron
C.) proton
D.) quark
Answer:
C proton hope it helps <3
Explanation:
A calculation based upon _______is only as accurate as the device used for measurement.
Which statement best describes how temperature, humidity, and pressure vary within an air mass?
I will mark brainliest
Answer:
d
Explanation:
it's the only one that seems to make sense
Why is it important for us to study isotopes?
Answer:
it is useful in diagnostics and treatment applications
Gina is trying to reduce the number of indoor pollutants in her home. Indoor pollutants include pet hair and dust, which are (gases, smoke, allergens, smog), and radon and carbon monoxide, which are (gases, smog, allergens, smoke)
Gina is trying to reduce the number of indoor pollutants in her home. Indoor pollutants include pet hair and dust, which are (c) allergens and radon and carbon monoxide, which are (a) gases.
Allergens are the substances that trigger the immune system of an organism and also produce allergic effects. Allergens can induce symptoms like: redness, itching, sneezing, coughing, etc. The examples of allergens are pollens, certain microbes, dust, pet hair, etc.
Radon is a highly poisonous and radioactive gas present in the environment. It is one of the major causes for lung cancer. It is inert and colorless in nature. Radon is present in environment due to decay of uranium which is present in soil naturally.
The question is incomplete, the complete question is:
Gina is trying to reduce the number of indoor pollutants in her home. Indoor pollutants include
A- pet hair and dust, which are:
(a) gases, (b) smoke, (c) allergens, (d) smog; and
B- radon and carbon monoxide, which are:
(a) gases, (b) smog, (c) allergens, (d) smoke.
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