Answer:
The first ionization energies (I1) of the alkaline earth metals are not as low as the alkali metals. The alkaline earth metals are therefore less reactive than the alkali metals (Be and Mg are the least reactive of the alkaline earth metals). Several physical properties of these elements are compared in Table 7.7.
burning sugar is a chemical change give reason?
Burning a sugar cube is a chemical change. Fire activates a chemical reaction between sugar and oxygen. The oxygen in the air reacts with the sugar and the chemical bonds are broken. Burning sugar leads to reaction of sugar with oxygen in air and leads to formation of carbon dioxide and water. The change is irreversible and is thus a chemical change
How many moles of oxygen are required to react completely with 5 mol C8H18?
Answer:
62.5 moles of O₂.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2C₈H₁₈ + 25O₂ —> 16CO₂ + 18H₂O
From the balanced equation above,
2 moles of C₈H₁₈ reacted with 25 moles of O₂.
Finally, we shall determine the number of mole of O₂ needed to react with 5 moles of C₈H₁₈. This can be obtained as shown below:
From the balanced equation above,
2 moles of C₈H₁₈ reacted with 25 moles of O₂.
Therefore, 5 moles of C₈H₁₈ will react with = (5 × 25) / 2 = 62.5 moles of O₂.
Thus, 62.5 moles of O₂ is needed for the reaction.
what do you mean by acceleration due to gravity of a body is 10 metre per second square
Answer:
If a body is accelerated by 10m/s^2, it means that the body's speed (or velocity to be precise) is increasing by 10m/s every second. That is, if the initial ...
How many molecules are in 35.5 grams of carbon dioxide?
Answer:
you have to use the avogadro's constant of 6.023×10^23 to calculate the number of molecules of carbon dioxide.and you also have to use the molecular mass which is 44.
35.5/44×6.023×10^23
=4.85×10^23
I hope this helps and sorry if it's wrong
10. Fuel oil, gasoline, kerosene and naphtha are four fractions obtained from the fractional
distillation of petroleum.
What is the order of the boiling points of these fractions?
Answer:
option b
Explanation:
answer from gauth math
What is the valency of halogens?why
Answer:
-1
Explanation:
Which of the following are held together by nonpolar covalent bonds?
The Periodic Table
A. Atoms of phosphorus (P) and chlorine (CI)
B. Atoms of chlorine (CI)
C. Atoms of chlorine (CI) and magnesium (Mg)
D. Atoms of magnesium (Mg)
Answer:
Answer: Atoms of chlorine (CI) and magnesium (Mg)
Answer: Atoms of chlorine (CI) and magnesium (Mg)is your answer
Jane wants to study how a person's heart and lungs respond to intense
exercise. She measures the heart rate and breathing rate of 10 people before,
during, and after a 5K race. Which body systems is she studying?
A. Cardiovascular and respiratory
B. Skeletal and urinary
C. Digestive and nervous
D. Muscular and reproductive
SUBMIT
A cactus needle is a structure made of different tissues that work together to protect the plant from animals that might want to eat it. What level of body organization does a cactus needle represent?
A. Cell
B. Organ
C. Cell system
D. Body system SUBMIT
Which of the following elements would you expect to be most reactive, based
on the number of valence electrons it has?
Answer:
C. Lithium
Explanation:
This image describes the trend in reactivity. Group 1 metals are always the most reactive so yeah :)
Emission and abpsorption spectra from a given atom or molecule can tell us: Group of answer choices the composition of substances, even at great distances away, by identifying its uniques spectral fingerprint. The motion toward or away from us based on the doppler effect and corresponding red shift or blue shift The temperature of an object by using Wien's Law. All of the above.
Answer:
The motion towards or away from us based on the Doppler effect and corresponding red shift or blue shift.
Explanation:
The emission and absorption spectra demonstrates the lines where light has been absorbed by the atoms. The spikes can be observed due to atoms releasing photons at those wavelengths. Infrared and ultra violet waves can be observed during spectroscopy.
How did elements get to earth?
the universe formed through the big bang explosion, all of the elements on Earth have been cooked for billions of years in stars and then released in the universe through super- nova explosions.
We have two surfaces A and B where same amount of Force is acting. Area of Surface A is greater than Area of Surface B. which of the following will be true *
1 point
Pressure on Surface A > Pressure on Surface B
Pressure on Surface B > Pressure on Surface A
Pressure does not depend on area
Pressure on Surface A= Pressure on Surface B
Answer:
Pressure on Surface A > Pressure on Surface B
Explanation:
Pressu
re on Surface B > Pressure on Surface A
True or false, the four units that must always be used when using the ideal gas law are liters, atm, Kelvin, and grams
Answer:
False grams is not used
Explanation:
IDEAL GAS LAW
The ideal gas law states that PV = NkT, where P is the absolute pressure of a gas, V is the volume it occupies, N is the number of atoms and molecules in the gas, and T is its absolute temperature.
It is necessary to use Kelvin for the temperature and it is conventional to use the SI unit of liters for the volume. However, pressure is commonly measured in one of three units: kPa , atm , or mmHg . Therefore, R can have three different values.
g) silver nitrate + magnesium chloride → silver chloride + magnesium nitrate
Answer:
AgNo3+Mgcl2--->Agcl2+Mg(No3)2
I hope this helps
a gas has a volume of 7L and a mass of 4.44*10^5 micrograms. what is it's density
Answer:
Explanation:
D = mass/volume.
for the units, I'll take it in g/L but I don't know which units you want.
4.44*10^5 mg = 0.444 grams.
0.444/7 = 0.0634 g/L
Help! Can somebody explain the answer and how they got it?
"Write the equation for the first ionization of potassium."
Answer:
K°(g)* + 419 Kj/mole => K⁺(g) + e⁻
Explanation:
1st ionization step for potassium is the ionization of the 4s¹ electron. This requires 419 Kj/mole energy (endothermic). The reaction equation is ...
K°(g)* + 419 Kj/mole => K⁺(g) + e⁻
*note: Ionization of group IA metals requires they be in gas phase. That is, as shown by the Born-Haber Cycle** for formation of ionic compounds ...
K°(s) + 89.24 Kj/mole => K°(g); then ...
K°(g) + 419 Kj/mole => K⁺(g).
**Recommend review of Born-Haber cycle for formation of ionic compounds.
The process of diffusion can be described as: Movement of water from the area of high concentration of solute to the area of low concentration of solute. Movement of solute from the area of low concentration of solute to the area of high concentration of solute. Movement of water from the area of low concentration of solute to the area of high concentration of solute. Movement of solute from the area of high concentration of solute to the area of low concentration of solute.
Answer:
Movement of water from the area of high concentration of solute to the area of low concentration of solute.
Explanation:
Diffusion can be defined as the movement of gas molecules from a region of high concentration to a region of lower concentration until an equilibrium is attained or reached. This mixing of gas molecules in the liquid or gaseous state is due to their kinetic energy of random motion i.e without requiring bulk motion.
This ultimately implies that, diffusion is a phenomenon through which gas molecules in either a gaseous or liquid state spread out in response to a concentration gradient, which is simply the difference in concentration of the gases across a space.
During diffusion, molecules move from areas of high concentration to areas of low concentration. Also, diffusion does not require energy to move molecules.
Hence, the process of diffusion can be described as movement of water from the area of high concentration of solute to the area of low concentration of solute.
A solute can be defined as a substance that is typically dissolved in a liquid solvent such as water, coffee, tea, etc., to produce a solution.
6. 240J of electric energy flows into a certain light bulb every second, and some energy is transformed into
light energy while some 'waste' thermal energy is also generated. If 200J of thermal energy is generated each
second, what is the efficiency of this bulb? (Hint: Pay good attention to what energy values you've been
given, before you start plugging them into the efficiency formula.)
Looking for
Solution
Given
I
Relationship Formula
Answer:
don't know
Explanation:
try it your self
try it your self
try it your self
try it your self
try it your self
try it your self
what is electronic configuration?
Answer:
In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals.
15. The starting diol for this molecule is
O A. ethanol.
O B. propan-1,3-dioic acid.
O C. propan-1,3-diol.
O D. ethan-1,2-diol.
Hope my answer is helpful to you ☺️
Arrange the steps in order to describe how photons and carbon dioxide (CO2) contribute to the warming of Earth.
CO2 in the atmosphere absorbs infrared
photons.
CO2 in the atmosphere emits infrared photons back toward Earth.
Photons from the Sun strike Earth and become infrared photons.
Earth radiates infrared photons into the atmosphere
The Sun radiates sunlight (visible)
photons
The Sun radiates sunlight (visible) photons
Photons from the Sun strike Earth and become infrared photons.
Earth radiates infrared photons into the atmosphere
CO2 in the atmosphere absorbs infrared photons.
CO2 in the atmosphere emits infrared photons back toward Earth.
Certain gases are known to contribute towards global warming. Such gases are called greenhouse gases. The infrared rays from the sun are absorbed by these gases as they are re-emitted from the earth and re-emitted.
The sun radiates photons to the earth which is re-radiated into outerspace from the earth's surface. CO2 and other greenhouse gases absorbs these gases and re-emit them to the earth thereby causing a gradually rise in the temperature of the earth called global warming.
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1a.calculate the relative formula mass of magnesium oxide when the relative atomic masses are O=16 Mg=24
1b.calculate the percentage by mass of magnesium in magnesium oxide
here's the answer to your question
The relative mass of the magnesium oxide (MgO) is equal to 40 g. The percentage by mass of magnesium in MgO is 60 %.
What is the mass percentage?The mass percentage of any element in a particular compound can be calculated from the number of parts by mass of the element in 100 parts by mass of a given compound.
Calculate the molar mass of the given compound by adding the atomic masses of the present elements. Then, the percentage of each element can be determined by dividing the total mass of the element by the molar mass of the compound multiplied by 100.
Given, the molecular formula of magnesium oxide is MgO. The atomic mass of Mg and O is 24 g and 16 g respectively.
The relative formula mass of the MgO = 40 g/mol
The mass percentage of the Mg = (24/40) × 100 = 60 %
Therefore, the mass percentage of the Mg in MgO is equal to 60 %.
Learn more about the mass percentage, here:
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which statement best describes the polarity of the molecule Sil4
a. it is polar, because the bond polarities add together in a tetrahedral molecule
b. It is non-polar, because the bond polarities cancel each other out in a tetrahedral molecule
c. it is non-polar, because the bonds between silicon (si) and iodine (I) are not polar
d. it is polar, because the bond polarities add together in a trigonal-planar molecule
The boiling points of diatomic halogens are compared in the table.
Boiling Points of Diatomic
Halogens
Molecule
Boiling Point
F2
-188 °C
Cl2
-34 °C
Br2
59 °C
12
184°C
Which of the following statements best explains the trends in boiling points?
The atomic size increases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.
The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.
Which of the following statements best explains the trends in boiling points?
A. The atomic size increases down the group, and this decreases the strength of the intermolecular forces.
A is incorrect
B. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.
B is incorrect
C. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.
C is correct
D. The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.
D is incorrect
The boiling point increase down a group because the total number of electrons increases down the group, and this increases the strength of the intermolecular forces. Hence option C is correct.
What is boiling point?Boiling point of a substance is the temperature at which the substance changes from its liquid state to vapour state. Boiling point of a molecule or compounds depends on the bond type, molecular weight, temperature and pressure.
For ionic compounds, boiling point will be higher since ionic bonds are stronger than covalent compounds. There is a periodic trend for the physical properties such as boiling point for elements in periodic table.
Down a group, the number of electrons increases and the atomic size also as well as the ionic character increases down a group . These two facts leads to higher intermolecular attraction, thus more temperature have to applied to weaken the bonds.
Higher temperature to be applied means the boiling point of the substance is higher. Therefore, boiling point down a group increases because of the higher intermolecular attraction as said in option C.
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What exactly is a proton? Is it a member of the periodic table?
The atomic number is the number of protons in the nucleus of an atom. The number of protons define the identity of an element (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).
What information does the percent composition of an atom in a molecule
give?
A. The relative number of atoms one element contributes to a
molecule
B. The relative amount of mass an atom contributes to a molecule
C. The total mass that element contributes to a molecule
D. The total number of atoms of that element in a molecule
C.
This is basically the definition of percent composition which is how much mass a element contributes to a specific molecule.
Answer: B.
Explanation:
the relative amount of mass an atom contributes to a molecule
PLZ HELP ME WITH MY WORK
For his science fair project, Martin studied the growth of trumpet vines. He grew 20 trumpet vines. All of the conditions were the same, except that he grew 10 in a flower bed without support and 10 in a flower bed near a trellis. The stems of the vines near the trellis twisted around the trellis, and these Yines grew tall and seemed much healthier than the vines grown without a trellis. In fact, four of the vines grown without a trellis died. Which characteristic of living things were the trumpet vines displaying as the stems twisted around the trellis?
A. Movement
B. Response to a stimulus
C. Use of energy
D. Reproduction
Answer:
it's B
Explanation:
Climbing plants require an external support to grow vertically and enhance light acquisition. Vines that find a suitable support have greater performance and fitness than those that remain prostrate. Therefore, the location of a suitable support is a key process in the life history of climbing plants
100cm³ of ethane gas diffuses through a porous plug in 100 seconds.What is the molecular mass of the gas Q if 100cm³ of the gas diffuses through the same plug in 121 secknds under the same condition?(C=12.0,H=1.0)
Answer:
The molar mass of gas Q is 43.923 g/mol
Explanation:
The given volume of ethane gas that diffuses through a porous plug in 100 seconds = 100 cm³
Therefore;
The rate of diffusion of ethane gas through the porous plug, [tex]v_{ethane}[/tex], is given as follows;
[tex]v_{ethane}[/tex] = (100 cm³/100 s) = 1 cm³/s
The molar mass of ethane, C₂H₆ = 2×12 g/mol + 6×1 g/mol = 30 g/mol
The given volume of gas, Q, that diffuses through a porous plug in 121 seconds = 100 cm³
∴ The rate of diffusion of the gas, Q, [tex]v_Q[/tex] = 100/121 cm³/s
Graham's Law of diffusion states that the rate of diffusion of a gas is inversely proportional to the square root of the molecular mass of the gas
Mathematically, we have;
[tex]\dfrac{v_A}{v_B} =\sqrt{\dfrac{m_B}{m_A} }[/tex]
Where;
[tex]v_A[/tex] = The rate of diffusion of gas A
[tex]v_B[/tex] = The rate of diffusion of gas B
[tex]m_A[/tex] = The molar mass of the gas A
[tex]m_B[/tex] = The molar mass of the gas B
Therefore, for ethane and gas Q, measured under the same condition, we have;
[tex]\dfrac{v_{ethane}}{v_Q} =\sqrt{\dfrac{m_Q}{m_{ethane}} }[/tex]
[tex]\dfrac{1 \ cm^3/s}{\dfrac{100}{121} \ cm^3/s} =\sqrt{\dfrac{m_Q}{30 \ g/mol} }[/tex]
[tex]m_Q = \left ({\dfrac{121}{100} } \right) ^2 \times 30 \ g/mol = 43.923 \ g/mol[/tex]
The molar mass of gas Q, [tex]m_Q[/tex] = 43.923 g/mol.
During a reaction, the enthalpy of the reactants and the products are not equal. What does this result in?
O A. Spin of electrons is reversed
O B. Change in chemical composition
O C. None of these
D. Absorption or release of energy
Answer:c
Explanation:
Answer: C
i think none of these
Explanation:
