Answer:
B. all organisms are made of at least one cell.
C.cells are the building blocks of life.
D.all cells come from preexisting cells
Explanation:
According to the cell theory that was proposed via the contribution of three scientists in 1830's namely: Matthias Schleiden, Theodor Schwann, and Rudolf Virchow, the following was stated:
- Cells are the basic and fundamental unit of life
- Living organisms are made up of one or more cells
- All cells arise from pre-existing cells.
From the above components, the following are said to be true and correlate with the universal cell theory:
B. all organisms are made of at least one cell.
C.cells are the building blocks of life.
D.all cells come from preexisting cells
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Answer:
B
Explanation:
A chemical reaction equation is balanced if the number of atoms of each element on the right hand side of the reaction equation is the same as the number of atoms of the same element on the left hand side of the reaction equation.
By inspection, the chemical reaction written in the question is a balanced chemical reaction equation.
However, the statement in option B that more molecules of N2 are needed to produce NH3 than molecules of H2 is a false statement since only one mole of N2 and three moles of H2 are required to produce NH3 according to the reaction equation as written in the question.
Given the table below, what is the chemical formula for a compound between Rb and the nitrate ion NO3-1?
nitrate ion NO3-1
phosphate PO4-3
sulfate SO4-2
acetate C2H3O2-1
ammonium NH4+1
chromate CrO4-2
carbonate CO3-2
dichromate Cr2O7-2
permanganate MnO4-1
sulfite SO3-2
RbNO 3
Rb(NO 3) 2
Rb 2NO 3
Rb 2(NO 3) 3
Answer:
b
Explanation:
The chemical formula for a compound between Rb and the nitrate ion NO₃-1 is Rb(NO₃)₂. Hence, option B is correct.
What is the chemical formula?Chemical formulas can be written for elements, compounds, and molecules. A compound is a substance made up of two or more different elements in a fixed ratio, and its formula shows the types of atoms and the number of each atom in the compound.
Rb(NO₃)₂ is the chemical formula for rubidium nitrate. It is an ionic compound composed of one rubidium cation (Rb+) and two nitrate anions (NO₃-) held together by ionic bonds.
The Rb+ ion has a charge of +1 and the NO₃- ion has a charge of -1, so two nitrate ions are needed to balance the charge of one rubidium ion. The overall charge of the compound is neutral.
Thus, option B is correct.
To learn more about the chemical formula, follow the link:
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m%of solution containing 100 gram of NaCl dissolved in 500g of water
Answer:
16.7 %(m/m)
Explanation:
The percent by mass of a solution (% m/m) is defined as 100 times the ratio of the mass of solute (The substance in the lower amount, NaCl) and the mass of the solution = Mass solute + Mass Solvent (water).
Mass Solution:
100g NaCl + 500g water = 600g solution
Mass Percent:
100g NaCl / 600g solution * 100
= 16.7 %(m/m)
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Answer:
1.B
2.C
3.D
Explanation:
In the first question, the valence in XH4 belongs to the X. So when it reacts with oxygen with always a valence of two, they cancel out remaining 2 making it XO2.
In the second question the 2 belongs to Y as we all know Sodium is atomic number 11 with a valence of one, so they exchanged valence.
When Y2 reacts with chlorine with atomic number 17 and valence 1,they exchange valencies making it YCl2.
In the third question, 2belongs to Y, so when it reacts with aluminum with atomic number 13 and valence 3,they exchange valencies making it Al2Y3
the pH of a solution is 2.0. what is the [OH^-] concentration?
Which of the Following Correctly Balances this Equation? _H2+_Cl2 --> _HCl
An expandable balloon contains 3.50 dm3 of helium at 101. kPa and 23.0oC. What volume will the balloon occupy when the pressure drops to 85.0 kPa and the temperature is 10.0oC?
Answer:
3.98dm³
Explanation:
Using combined gas law equation:
P1V1/T1 = P2V2/T2
Where;
P1 = initial pressure (kPa)
P2 = final pressure (kPa)
V1 = initial volume (dm³)
V2 = final volume (dm³)
T1 = initial temperature (K)
T2 = final temperature (K)
According to the provided information in this question:
V1 = 3.5dm³
V2 = ?
P1 = 101 kPa
P2 = 85.0 kPa
T1 = 23.0°C = 23 + 273 = 296K
T2 = 10.0°C = 10 + 273 = 283K
Using P1V1/T1 = P2V2/T2
101 × 3.5/296 = 85 × V2/283
353.5/296 = 85V2/283
Cross multiply
296 × 85V2 = 353.5 × 283
25,160V2 = 100,040.5
V2 = 100,040.5 ÷ 25,160
V2 = 3.98dm³
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Pls Answer
What happens when dilute sulphuric acid is poured on a copper plate ?
Answer:
No observable change.
Explanation:
Copper renders dilute sulphuric acid passive, no reaction.
H2SO4+Cu-->CuSO4+H2
Explanation:
THIS IS THE CORRECT ANSWER
Compare the stability of primary, secondary and tertiary carbocation
Answer:
Primary carbocations are most stable, Secondary carbocations are more stable, tertiary carbocations are least stable.
Explanation:
This is due to Asterric hinderance.
Obtener la fórmula empírica de un compuesto cuya composición centesimal reporta: Cr: 26,53 % , S: 24,52 % y O: 48,96%. Dato: m.A. [Cr= 52 , S= 32]
Respuesta:
Cr₂S₃O₁₂
Explicación:
Primer paso: Dividir el porcentaje en masa de cada elemento por su masa atómica
Cr: 26,53/52 = 0,510
S: 24,52/32 = 0,766
O: 48,96/16 = 3,06
Segundo paso: Dividir todos los números por el más pequeño (0,510)
Cr: 0,510/0,510 = 1
S: 0,766/0,510 = 1,5
O: 3,06/0,510 = 6
Tercer paso: Multiplicar todos los números por algún número que haga que todos sean enteros (2)
Cr: 1 × 2 = 2
S: 1,5 × 2 = 3
O: 6 × 2 = 12
La fórmula empírica es Cr₂S₃O₁₂.
Answer: The empirical formula of the compound becomes [tex]Cr_2S_3O_{12}[/tex]
Explanation:
The empirical formula is the chemical formula of the simplest ratio of the number of atoms of each element present in a compound.
Let the mass of the compound be 100 g
Given values:
% of Cr = 26.53%
% of S = 24.52%
% of O = 48.96%
Mass of Cr = 26.53 g
Mass of S = 24.52 g
Mass of O = 48.96 g
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.Molar mass of Cr = 52 g/mol
Molar mass of S = 32 g/mol
Molar mass of O = 16 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of Cr}=\frac{26.53g}{52g/mol}=0.510 mol[/tex]
[tex]\text{Moles of S}=\frac{24.52g}{32g/mol}=0.766 mol[/tex]
[tex]\text{Moles of O}=\frac{48.96g}{16g/mol}=3.06 mol[/tex]
Step 2: Calculating the mole ratio of the given elements.Calculating the mole fraction of each element by dividing the calculated moles by the least calculated number of moles that is 0.510 moles
[tex]\text{Mole fraction of Cr}=\frac{0.510}{0.510}=1[/tex]
[tex]\text{Mole fraction of S}=\frac{0.766}{0.510}=1.5[/tex]
[tex]\text{Mole fraction of O}=\frac{3.06}{0.510}=6[/tex]
Multiplying the mole fraction of all the elements by 2, in order to make it as a whole number
[tex]\text{Mole fraction of Cr}=(2\times 1)=2[/tex]
[tex]\text{Mole fraction of S}=(2\times 1.5)=3[/tex]
[tex]\text{Mole fraction of O}=(2\times 6)=12[/tex]
Step 3: Taking the mole ratio as their subscripts.The ratio of Cr : S : O = 2 : 3 : 12
Hence, the empirical formula of the compound becomes [tex]Cr_2S_3O_{12}[/tex]
what is chemical reaction
Answer:
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.
Explanation:
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Which of the following is correct for adsorption theory of Heterogeneous catalysis? Statement-I : This theory explains why the catalyst remains unchanged in mass and chemical composition at the end of the reaction. Statement-II : This theory explains the action of catalytic promoters and catalytic poison.
Statement-I is true, Statement-II is false
Statement-I is false, Statement-II is true
Both Statement-I and Statement-II are true
Both Statement-I and Statement-II are false
please answer rightly
Answer:
The correct answer is - Statement I is true, Statement-II is false.
Explanation:
In which orbital would the valance electrons for carbon(C) be placed?
Carbon has an atomic number of 6 so its electron configuration will be 1s² 2s² 2p². It has two orbitals as indicated with the 2 as its period number with the outer orbital have 4 valence electrons. So carbon is in the p-orbital, period 2 and in group 4.
Which of the following are 'natural polymers
(bio-molecules)? Choose all that apply.
nylon
teflon
silk
cellulose
proteins
polyethylene
What is natural selection
Answer:
Hey there
Explanation:
The process where organisms better adapted to their environment tend to survive and produce more offspring is called natural selection. It is one of the points of Darwinism by Charles Darwin.
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Answer: protein bar,it gives alot of energy and wont upset your stomach!!
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Answer:
A) Q + XZ = X + QZ is a single displacement reaction.
B) Q + Z = QZ is a synthesis reaction
C) QT = Q + T is a decomposition reaction
D) QT + XZ = QZ + XT is double replacement reaction.
Explanation:
A) Q + XZ = X + QZ
This is a single displacement reaction because it is one in which one element is substituted for another one in a compound. In this case X is substituted for Q.
B) Q + Z = QZ
This is a synthesis reaction because Q and z combine to form a single product QZ.
C) QT = Q + T
This is a decomposition reaction because the compound QT breaks down to form 2 simpler substances Q and T.
D) QT + XZ = QZ + XT
Thus is a double replacement reaction because QT and XZ have exchanged cations to form new compounds QZ and XT
What is the concentration , in grams per liter , of a solution containing 6 mEq of calcium chloride ( CaCl2 ) per milliliter ? ( Ca = 40 , Cl = 35.5 , H = 1 , 0 = 16 )?
Answer:
333g/L
Explanation:
The moles of CaCl2 in 6mEq are:
6mEq * (1mmol / 2mEq) = 3mmol CaCl2.
2Eq / mol because the charge of Ca is 2+
The mass is:
3mmol CaCl2 * (111mg/mmol) = 333mg = 0.333g
Molar mass: 2*35.5g/mol + 40g/mol = 111g/mol = 111mg/mmol
The liters are:
1mL * (1L / 1000mL) = 1x10⁻³L
The concentration in grams per liter is:
0.333g / 1x10⁻³L = 333g/L
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Chemistry
Answer:
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NUMBERS 6-8 URGENT PLEASE
Answer:
See explanation
Explanation:
9g of water contains : 9g/18 g/mol = 0.5 mole of water
1) 2 moles of hydrogen yields 2 moles of water
x moles of hydrogen yields 0.5 moles of water
x= 2 × 0.5/2 = 0.5 moles of hydrogen
Mass of hydrogen = 0.5 moles × 2 = 1 g of hydrogen
2) Number of moles of Al(OH)3 = 468 g/ 78 g/mol = 6 moles
2 moles of Al(OH)3 yields 3 moles of H2O
6 moles of Al(OH)3 yields 6 × 3/2 = 9 moles of H20
Mass of water =9 moles × 18 g/mol = 162 g of water
3) There are 13 oxygen atoms in the compound.
Mass of each oxygen atom = 16 g
Total mass of oxygen atoms = 13 × 16 = 208 g
describe about chromatography
Answer: Chromatography is a technique for the separation of a mixture. The mixture is dissolved in a fluid (gas, solvent, water, ...) called the mobile phase, which moves it through a system (a column, a capillary tube, a plate, or a sheet) on which is fixed a material called the stationary phase.
Explanation:
The relative atomic mass of helium is 4 and the relative atomic mass of bromine is 80. How many helium atoms will be as one bromine atom?
Answer:
80÷4=20 Helium atoms
Explanation:
Because one helium atom is a quarter of of one bromine atom
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Answer:
See explanation
Explanation:
The can chiller has a cooling system which expels heat around the immediate vicinity of the can chiller.
Let us remember that convection is a mode of heat transfer that occurs as a result of the actual movement of the particles of a substance. In this case, we are going to consider the movement of air molecules.
As the can chiller expels heat, the air molecules around the can chiller become heated and less dense and begin to move away from the can chiller. They are quickly replaced by cold denser air.
This process of cycling of hot/cold air molecules is known as a convection current. It is set up as a result of the working of the can chiller.
Thompson's experiments with cathode ray tube lead to the invention of what?
Answer:
Thompson's experiments with cathode ray tube showed that every atom contains a small amount of negatively charged subatomic particles. Thomson proposed the plum pudding model of the atom.
Explanation:
What is meant by term valency? Explain it in terms of electrons donations and acceptance.
Answer:
Valency can be defined as a measure of the combining power of a chemical element with other atoms to form a molecule or chemical compound.
Explanation:
An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.
Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.
In Chemistry, electrons can be defined as subatomic particles that are negatively charged and as such has a magnitude of -1.
Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others. Thus, this property is typically used to determine the chemical properties of elements.
Valency can be defined as a measure of the combining power of a chemical element with other atoms to form a molecule or chemical compound.
Typically, valency is measured by the amount of hydrogen atoms that a chemical element can combine with or displace to form a molecule or chemical compound.
For example, Oxygen has a total number of eight (8) electrons while neon has total number of ten (10) electrons. Therefore, an atom of oxygen is able to gain (accept or receive) two (2) more electrons in order to have the same electron arrangements as the noble gas i.e an atom of neon with an atomic number of 10.
2. List and elaborate on at least two limitations of the 24-hour recall as a
method of diet assessment (Each item .5 pt for a total of 1 pt, support
for each response 5 pt for a total of 1 pt = 2 pts)
Answer:
The correct answer is - may not be typical, and participant burden.
Explanation:
The 24-hour recall is nothing but a retrospective method of diet assessment. In this method, an individual is interviewed about his or her diet consumption during the last 24 hours.
The disadvantages or limitations of this method include the inability of a single day's intake to describe the typical diet, multiple recalls to intake, cost and administration time; participant burden, have to recall to reliably estimate usual intake.
my answer was 10 and it’s telling me it’s wrong..what did i do wrong?
Answer:
1.586x10^-9
Explanation:
To make a multiplication in scientific notation we need to multiply the coefficients and sum the exponents:
Coefficients: 2.600 * 6.1000 = 15.86
Exponents: -5 + (-5) = -10
The result is:
15.86x10^-10
As the scientific notation must be given with only 1 number in the left of the point:
1.586x10^-9Please help me with this in the picture I need 8 thing wrong and 8 what should they do right
What is the molar mass of tetraethyl lead, Pb(C2H5)4
So, the molar mass of tetraethyl lead is
[tex]207.2+8(12.011)+20(1.00794)=\boxed{323.4468 \text{ g/mol}}[/tex]
Please answer the question
Answer:
Oxygen is the nearest noble gas