Answer:
4
Explanation:
The Atomic number of beryllium is 4, which means that it has 4 protons.
An unknown gas with a formula of HX is contained in a 25.0 L tank at 1.2 atm and 25.0 oC. What is the chemical formula of the gas if the mass of the gas is 44.7 g?
Answer:
HCl
Explanation:
Volume = 25L
Temperature = 25.0 oC + 273 = 298 K (Converting to kelvin units)
Pressure = 1.2 atm
Mass of gas = 44.7g
Formular of gas = HX
To solve this, we have to know the identity of X. One qay to do that is by obtaining the molecular mass of the compound.
To get the molar mass, we need the number of mole.
Using the ideal gas equation;
PV = nRT
where R = gas constant = 0.082 057 L atm K−1 mol−1
n = PV / RT
n = 1.2 * 25 / 0.082 057 * 298
n = 30 / 24.45
n = 1.227 mol
The relationship between number of moles and molar mass is given as;
Nummber f moles = mass / molar mass
Molar mass = mass / Number of moles
Molar mass = 44.7 / 1.227
Molar mass = 36.43 g/mol
Molar mass of gas X = Molar mass of H + Molar mass of X
36.43 = 1 + X
X = 36.43 - 1 = 35.43
Chlorine is the only element with molar mass approximate to 35.43
Hence X = Cl
The chemical formular = HCl
GIVEING BRAINLIST
ATP is a(1 point)
storable form of energy.
usable form of energy.
form of energy that can be used and stored.
form of energy that can be stored and released as heat.
Answer:
ATP is a stored form of energy
Explanation:
it is the main source of this
What’s two options are examples of chemical changes
Answer:
what are the options? I'll edit my answer to the correct one once you inform me lol
The adult dosage of diphenhydramine, an antihistamine, is 50.0 mg. A 24 lb child should only receive 20.0% of the adult dose. Calculate this dose in milligrams.
The amount that the child should receive is 10 mg.
What is a dose?The term dose refers to the amount of drugs that a person should take. The dose of the drug is in proportion to the magnitude of the illness. The more severe the symptoms, the higher the dosage.
Since the child is to receive only 20% of the adult dose, we have;
20/100 * 50.0 mg
= 10 mg
The amount that the child should receive is 10 mg.
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Type the following formulas in the boxes in order of increasing boiling point: RbF, CO2, CH3OH, CH3Br.
Answer:
CO2 < CH3Br < CH3OH < RbF
Explanation:
The boiling point of the compounds can be determined in terms of the strength of the intermolecular forces present in each compound.
Intermolecular forces are weak forces joining non-polar and polar molecules together. We have London dispersion forces, dipole-dipole forces of attraction, and hydrogen bonding.
London dispersion forces are weak attractions found between non-polar and polar symmetrical molecules. They are the weakest of all the electrical forces and they act between atoms and molecules e.g CO2
The dipole-dipole attractions are forces of attraction existing between polar unsymmetrical molecules. The dipole-dipole force of attractions is much stronger than London dispersion forces but weaker than Hydrogen bonding. e.g CH3Br
Hydrogen bonding is a special dipole-dipole attraction between polar molecules in which a hydrogen atom is directly joined to a highly electronegative atom (e.g. oxygen, nitrogen, or fluorine). Here, the bond in CH3OH is a hydrogen bond.
Ionic bonding is a bond that is formed between two kinds of atoms having a large electronegative difference such as in RbF,
Thus, in increasing order of boiling point;
CO2 < CH3Br < CH3OH < RbF
How can carbon dating be used to study the history of the earth?
Consider the reaction between NO(g) and 02(8) represented
below. What is the balanced equation for this reaction, and what is the
limiting reactant?
when nitric oxide reacts with oxygen GIVES Nitrogen dioxide.
NO(g)+ [tex]0_2[/tex]=2N[tex]O_2[/tex] is the balanced reaction
here, from the above reaction, we have found that
1 mole of NO and 2 mole of [tex]0_2[/tex] gives 2 mole of N[tex]O_2[/tex]
from the mole concentration, we can conclude that oxygen is limiting reactant.
A limiting reactant is an active ingredient in a reaction that is totally consumed by its conclusion. The limiting reactant determines how much product is produced in a chemical process.
In a chemical reaction, the reactants react in a stoichiometric sequence to produce the products. The limiting reactant is the one that is present in lower stoichiometric amounts. The amount of the product created depends on how much of the limiting reactant is used up in the reaction. Excess reactants are the additional reactants in the reaction besides the limiting reactants.
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True or false: oceans have no efect on the temperature on Earth’s land.
Will give out free Brainiest, I know there are thirsty people out there :D
Answer:
False
Explanation:
Answer
is it FALSE?
I always answer question but people don't ever give me brainiest that why i got 0
What is the mass (in grams) of 255ml of mercury if mercury has a density of 13.34 grams per ml? (Remember significant digits in answer)
The mass in grams of 255mL of mercury if it has a density of 13.34g/mL is 3401.7g.
How to calculate mass?The mass of a substance can be calculated by multiplying the volume of the substance by its density as follows:
Mass = density × volume
According to this question, 255mL of mercury has a density of 13.34g/mL. The mass is calculated as follows:
Mass = 13.34g/mL × 255mL
Mass = 3401.7g
Therefore, the mass in grams of 255mL of mercury if it has a density of 13.34g/mL is 3401.7g.
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A student jumps of a sled toward the west after it stops at the bottom of an icy hill. Based on the law of action-reaction, in what direction will the sled most likely move as the student jumps off
Answer:
East
Explanation:
Given Newton's third law of motion; "Action and reaction are equal and opposite", when a student jumps off a sled toward the west after it stops at the bottom of an icy hill, the sled will move in the East direction.
This is because, the force exerted on the sled is a reaction force and is opposite in direction to the force that thrusts the boy westward though equal in magnitude with the former.
What is the maximum number of electrons that can be present in each principal energy level of hydrogen?
Answer:
Each principal energy level has one sublevel containing one orbital, an s orbital, that can contain a maximum of two electrons.
Explanation:
Answer:
2n
Explanation:
5. Aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide. (a) Write a
balanced equation for this reaction. (b) How many grams of aluminum hydroxide can be obtained from
5.50 g of aluminum sulfide?
6.2
A1₂S3 + 6H₂O → 3H₂S + 2A1 (OH)3
53
a) A1₂S₃ + 6H₂O → 3H₂S + 2Al(OH)₃ +3H₂S
b) 5.72grams of aluminum hydroxide.
It demonstrates that each molecule of aluminum sulfide yields two molecules of aluminum hydroxide, or two molecules of Al(OH)3 for every molecule of aluminum sulfide.
Al(OH)3 has a molecular weight of 78 while Al2S3 has a molecular weight of 150. Starting with 5.5 grams of aluminum sulfide, we can set up the ratio by dividing it by 150 to get x/156.
5.5/ 150 = x/156
where x represents the quantity of Al(OH)3 that was created.
Since two moles of Al(OH)3 are created for every mole of Al2S3 that reacts, we utilize 156, which is twice as much as 78. As a result, we arrive at x = (5.5)(156)/150 = 5.72 gm. To the nearest decigram, we obtain 5.72grams of aluminum hydroxide.
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Can someone help me with number 5:/
So to answer this question first let's decribe precision vs accuracy.
Precision in this case means exact and accurate; in this scenario all of the dots next to each other mean that it is highly precise.
Whereas Accuracy means aiming for the middle of the circle in this case. Thus the accuracy is low, but the precision is high.
TLDR: It is highly precise but not accurate.
Look up "Accuracy vs. Precision: What’s the Difference?" for a better detailed example and solution.
Nuclear decay occurs according to first-order kinetics. How long will it take for a sample of radon-218 to decay from 99 g to 0.50 g? The half-life of radon-218 is 35 milliseconds.
a. 2.6 x 102 ms.
b. 2.0 10 ms.
c. 1.1 x 10 ms.
d. 6.6 x 102 ms.
Answer:
a. 2.6 x 102 ms
Explanation:
Initial mass [Ao] = 99 g
Final mass [A] = 0.50 g
Half life (t1/2) = 35 ms
Time ( t ) = ?
]The integrated rate law for first order reactions is given as;
To obtain k, we look at the expression for the half life of a first order reaction;
t1/2 = 0.693 / k
k = 0.693 / 35 = 0.0198 ms-1
ln[A] = ln[Ao] - kt
kt = ln[Ao] - ln[A]
t = ( ln[Ao] - ln[A] ) / k
t = ( ln(99) - ln (0.50) ) / 0.0198
t = 5.288 / 0.0198
t = 267.07 ms
correct option is;
a. 2.6 x 102 ms
which elements are solid at room temperature
Answer:bromine , neon , helium , argon , lithium , beryllium
Explanation:
Elements can be divided into three state that are solid, liquid and gas depending the intermolecular forces of attraction, distance between the particles etc. Lithium, beryllium, boron, carbon, sodium, magnesium, iron, copper, etc. are solid at room temperature.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Elements can be solid liquid or gas at room temperature.
Therefore, Lithium, beryllium, boron, carbon, sodium, magnesium, iron, copper, etc. are solid at room temperature.
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What nuclide undergoes fission to form molybdenum-103, atomic number 42, tin-131, atomic number 50, and two neutrons?
Element symbol: _______ mass number: _______
Answer:
The correct answer is Pu, 234.
Explanation:
In the given case, let us consider the reactant as X. Now the mass number (balanced) on both the sides will be,
Mass of X = Mass of Molybdenum + Mass of Tin + Mass of neutrons
M = 1 * 103 + 1 * 131 + 2 * 0
M = 234
Now the atomic number (balanced) on both the sides,
Atomic number of X = Atomic number of Molybdenum + Atomic number of Tin + Atomic number of neutrons
A = 1*42 + 1*50 + 2*1
A = 94
The atomic number 94 is for the element Plutonium, whose symbol is Pu. Thus, the reactant is 234-Pu.
Every neutral atom of a given element has the same number of what two subatomic particles?
A. Protons and neutrons
B. Protons and electrons
Answer:
B. Protons and Electrons
Explanation:
Protons have a positive charge and electrons have a negative charge. When an element contains the same number of both of those particles the charges will cancel out leaving the atom with a neutral charge, as neutrons already have a neutral charge.
Please help me I need these answers
Answer:
Q8) True
Q9) First ionization energy
Q10) Metal oxides
Explanation:
A common property of group one elements (alkali metals) is their combination with water to form basic solutions. E.g 2K(s)+2H2O(l)→2KOH(aq)+H2(g).
The distance of the outermost electron in the atom from the nucleus is inversely related to the first ionization energy. As the distance between the outermost electron and the nucleus in group 17 elements gets larger, the corresponding first ionization energies of elements in the group gets smaller.
Group 1 elements can combine with oxygen to give metal oxides. E.g 4K + O2 --> 2 K2O
calculate the pH of 5.9x10^-4
Answer:
The answer is 59
Explanation:
Helium decays to form lithium. Which equation correctly describes this decay? Superscript 6 Subscript 2 Baseline Upper H e right arrow Superscript 3 Subscript 3 Baseline Upper L i + Superscript 0 Subscript negative 1 Baseline e Superscript 6 Subscript 2 Baseline Upper H e right arrow Superscript 6 Subscript 3 Baseline Upper H + Superscript 0 Subscript negative 1 Baseline e Superscript 6 Subscript 2 Baseline Upper H e right arrow Superscript 6 Subscript 3 Baseline Upper L i + Superscript 0 Subscript negative 1 Baseline e Superscript 6 Subscript 2 Baseline Upper H e right arrow Superscript 6 Subscript 3 Baseline Upper L i + Superscript 0 Subscript 1 Baseline e
Answer:
Superscript 6 Subscript 2 Baseline Upper H e right arrow Superscript 6 Subscript 3 Baseline Upper L i + Superscript 0 Subscript negative 1 Baseline e
Explanation:
Helium decays by beta emission, in beta emission, the mass number of the parent and daughter nuclei are the same but the atomic number of the daughter nucleus increases by one hence it is found one place to the right of its parent in the periodic table.
Having said this, the decay of Helium to lithium may be written as follows;
6/2He -> 6/3Li + 0/-1e
Answer:
C
Explanation:
Edge 2020
A 1.00 g sample ofNH4N03 is decomposed in a bomb calorimeter. The temperature increases by 6.12 oc. What is the molar heat of decomposition of NH4N0.1
This question is incomplete, the complete question is;
A 1.00 g sample of NH4NO3 is decomposedin a bomb calorimeter. The temperature increases by 6.12°C. What is the molar heat of decomposition for ammonium nitrate?
Molar mass, NH4NO3 80.0 g/mol
Calorimeter Constant 1.23 kJ/°C
Answer:
the molar heat of decomposition for ammonium nitrate is - 602.4 kJ/mol
Explanation:
Given that;
change in temperature ΔT = 6.12 °C
Calorimeter Constant C = 1.23 kJ/°C
Molar mass, NH4NO3 = 80.0 g/mol
we know that;
Heat gained by the calorimeter (Q1) = Heat lost by the decomposition of NH4NO3 (Q2)
Q1 = C × ΔT
Q1 = (1.23 kJ/K) × (6.12 K) = 7.53 kJ
Q value we get becomes negative since we are talking about reaction and not calorimeter
hence
Q1 = - 7.53 kJ
now
1 g NH4NO3 decomposed, - 7.53 kJ of heat is released
so if 80 g which is 1 mol NH4NO3 decompose, the heat will be;
(80 g/mol x -7.53 kJ) / 1 g = - 602.4 kJ/mol
Therefore the molar heat of decomposition for ammonium nitrate is - 602.4 kJ/mol
what is percentage composition?
Answer:
The percent composition of a component in a compound is the percent of the total mass of the compound that is due to that component. To calculate the percent composition of a component in a compound: Find the molar mass of the compound by adding up the masses of each atom.
what is the difference between bio chemistry and organic chemistry
Answer:
Organic chemistry is the chemistry of carbon based compounds while biochemistry is the study of directly biologically relevant chemistry..pls mark as brainliestWhich type of precipitation occurs when the water vapor in a cloud freezes to form ice crystals?
Answer:snow i think
Explanation:
Answer:
snow
Explanation:
A physical change is when the form or shape of a substance changes, but
the chemical structure remains the same. *
True
False
Xenon tetrafluoride has two sets of lone pairs of electrons. What should be the relative positions of the two sets of lone pairs?Why?
Answer: Two equatorial positions so as to minimize the repulsion.
Explanation:
Formula used for calculating number of electrons :
[tex]\frac{1}{2}[V+N-C+A][/tex]
where,
V = number of valence electrons present in central atom = 8
N = number of monovalent atoms bonded to central atom = 4
C = charge of cation = 0
A = charge of anion = 0
Now we have to determine the hybridization of the [tex]XeF_4[/tex] molecule.
[tex]\frac{1}{2}[8+4-0+0]=6[/tex]
Bond pair electrons = 4
Lone pair electrons = 2
The number of electrons are 6 that means the hybridization will be [tex]sp^3d^2[/tex] and the electronic geometry of the molecule will be octahedral.
The molecular geometry will be square planar as two alternate positio ns will be occupied by lone pair of electrons so as to minimize the repulsion.
An atom does not have to have equal numbers of protons and _________________ in the nucleus.
Answer:
the answer is neurtons
Explanation:
Which produces the most energy? A. passing 5 kg of water through a hydroelectric power plant. B. fissioning 5 kg of uranium. C. burning 5 kg of gasoline. or D. fusing 5 kg of hydrogen.
Answer:
D. fusing 5 kg of hydrogen.
Explanation:
How many grams are in 0.040 moles zirconium (Zr)? Only 2 significant numbers?
Mass of Zirconium (Zr) in 0.040 moles : 3.6 g
Further explanationThe mole is the number of particles(molecules, atoms, ions) contained in a substance
1 mol = 6.02.10²³ particles
Can be formulated
N=n x No
N = number of particles
n = mol
No = Avogadro's = 6.02.10²³
Moles can also be determined from the amount of substance mass and its molar mass
[tex]\tt n(mol)=\dfrac{m(mass)}{MW(molecular~weight)}[/tex]
moles of Zirconium : 0.04
mass of Zirconium (MW=91,224 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=0.04\times 91,224\\\\mass=3.6~g[/tex]
How does having knowledge about viscosity may affect you in simple ways in your daily life?
Viscosity is an crucial factor in food preparation and serving. Cooking oils' viscosity may or may not change as they heat, but many become much more viscous as they cool.
What is viscosity?Viscosity refers to the resistance of a fluid (liquid or gaseous state) to a shape shift or mobility of neighboring portions relative to one another. Viscosity indicates flow resistance.
Gathering viscosity data on a material allows manufacturers to predict how the material will start behaving in the real world. For example, if toothpaste does not have the correct viscosity, it may be difficult or impossible to pump out of the tube.
Thus, it is important to have the knowledge of viscosity.
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