Answer:
Group 2A (or IIA) of the periodic table are the alkaline earth metals: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). They are harder and less reactive than the alkali metals of Group 1A. The name comes from the fact that the oxides of these metals produced basic solutions when dissolved in water, and they remained solids at the temperatures available to the ancient alchemists. Like the Group 1A elements, the alkaline earth metals are too reactive to be found in nature in their elemental form.
The alkaline earth metals have two valence electrons in their highest-energy orbitals (ns2). They are smaller than the alkali metals of the same period, and therefore have higher ionization energies. In most cases, the alkaline earth metals are ionized to form a 2+ charge.
The alkaline earth metals have much higher melting points than the alkali metals: beryllium melts at 1287ºC, magnesium at 649ºC, calcium at 839ºC, strontium at 768ºC, barium at 727ºC, and radium at 700ºC. They are harder metals than the Group 1A elements, but are soft and lightweight compared to many of the transition metals.
Salts of the Group 2A metals are less soluble in water than those of Group 1A because of the higher charge densities on the 2+ cations; nevertheless, many Group 2A salts are at least moderately soluble. Some Group 2A salts bond strongly to water molecules, and crystallize as hydrates; among these are Epsom salt, MgSO4·7H2O, and gypsum, CaSO4·2H2O.
Explanation:
Answer:
H2, N2, O2, F2, Cl2, Br2, I2
Explanation:
The 7 diatomic elements in the periodic table are Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine and Iodine.
Define valence electrons.
Answer:
Electrons on the outermost shell of an atom. They are responsible for the chemical properties of an atom.
The burning of fossil fuels contributes to the addition of greenhouse gases to the atmosphere. These gases trap thermal energy in the Earth’s atmosphere. Which of the following would be the most reasonable changes that could result from an increase in the burning of fossil fuels?
Explanation:
The burning of fossil fuels contributes to the addition of greenhouse gases to the atmosphere. These gases trap thermal energy in the Earth's atmosphere.
The materials which contain hydrocarbons which are generated from the remains of decay of plants and animals that are buried underground for many years are called fossil fuels.
What causes by burning fossil fuels?The burning of fossil fuels can affect the environment, climatic conditions and human health. The burning of fossil fuels produces large amount of green house gases like CO₂, CH₄, etc. The increase in the amount of green house gases increases the heat and temperature of the earth's surface which leads to global warming.
The increase of temperature due to global warming can cause rise in the sea level, the glaciers of the earth will melt and coastal areas will be submerged under water due to this.
The burning of fossil fuels also releases toxic gases like SO₂, NO₂ which can cause acid rain and the emission these gases causes air pollution.
Thus the burning of fossil fuels has adverse effects.
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que es y que define a los elementos quimicos
Un elemento químico, o un elemento, se define como un material que no puede descomponerse ni transformarse en otra sustancia por medios químicos. Cada elemento se identifica según la cantidad de protones que tiene en su núcleo atómico. Se puede crear un nuevo elemento agregando más protones a un átomo.
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ITZY :)
How many moles of hydrogen atoms are found in 1.50 • 10{24} molecules of C12 H22 O11
In the reaction below the total mass of calcium in the reactants is 40. What is the total mass of calcium in the products?
Answer:
40
Explanation:
The total mass of calcium in the products is 40
What is the total mass number?The mass number (represented by the letter A) is defined as the total number of protons and neutrons in an atom. Consider the table below, which shows data from the first six elements of the periodic table. Consider the element helium. Its atomic number is 2, so it has two protons in its nucleus.
How do you find the mass number?Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.
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4. One gram of of ............... contains one type of atoms. a. iron b. ammonia c. hydrogen chloride d. water
Answer: hydrogen chloride.
Explanation:
Explain why ions have a charge on them.
Answer:
An ion is a charged atom or molecule. It is charged because the number of electrons do not equal the number of protons in the atom or molecule. An atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.
The coefficients in a balanced chemical equation directly represent moles of reacting substances. true or false
The statement "The coefficients in a balanced chemical equation directly represent moles of reacting substances." is true.
What is a balanced equation?A balanced equation is one in which there is an equal number of atoms present on both sides of the reaction. When the atoms of elements in the reaction equal the atoms of elements or compounds in the products. The number of moles is similar before and after the reaction.
The chemical equation is the mathematical representation of any reaction, the number written on the front of the element or compound represents the number of atoms of the element present in the reaction. These numbers are called the coefficient of the chemical equation.
Thus, the statement is true, because the coefficients tell the mole of reacting substance.
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A yellow solid, W is soluble in water. Which method of separation can be used to obtain the solid W from an aqueous solution?
A Neutralisation
B Chromatography
С Distillation
D Crystallisation
changing the position of the .. increases or decreases your effort ..
A chemistry teacher adds red food coloring to water and students observed the dye spreading out to fill the container. Is the teacher
demonstrating a physical or chemical change?
Answer:
its obviously a chemical change
Explanation: Facts
The addition of the food color in water only causes the change in the cor of water but no new substance is formed. Therefore, the teacher is restarting the physical change.
What is a physical change?A physical change can occur when the characteristics of the matter change but the identity does not. Physical changes are classified as: reversible and irreversible. For example, the melting of water is reversible in nature since the melted ice cube will be refrozen.
Physical change can be described as a kind of change where only physical properties of matter such as odor, color, solubility, etc. can change. During physical changes, there is no chemical bonds are broken or formed between atoms of the substance.
The chemical composition as well as the chemical nature of the substance remains unchanged during a physical change. The molecules of matter can rearrange without changing the internal composition of matter.
Therefore, adding food color to water is a physical change as no new substance formed.
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how long does it take for chlorine to evaporate from water?
Answer:
1 to 5 days
Explanation:
275 KJ of energy was transferred to water at 15c. Calculate the mass of water that can be brought to its boiling point
Answer:
need points rn sorry bro hope u get ur answer
Explanation:
What would happen if we didn’t have the Milky Way
(b)
Analysis of a molecule of DNA showed that cytosine accounted for 42 per cent of the
content of the nitrogenous bases. Calculate the percentage of bases in the molecule
which would be thymine. Show your working.
8%
Explanation:
In a DNA molecule the no. of Adenine bases equal to that of Thymine bases
The no. of Cytosine bases equal to that of Guamine bases.
If we take no. of Thymine bases as x and no. of Cytosine bases as y,
Adenine + Thymine + Cytosine + Guamine = 100
x + x + y+y = 100
2( x+y) = 100
x+y = 50
y=42
therefore x= 50-42 = 8%
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What is the correct orientation of the bar magnet, based on the magnetic field
lines shown?
A. South pole on the top edge and north pole on the bottom edge.
B. North pole on the top edge and south pole on the bottom edge
C. South pole on the left end and north pole on the right end
D. North pole on the left end and south pole on the right end
Answer:
b
Explanation:
north is up south is bottom
Answer:
C. South pole on the left end and north pole on the right end
Explanation:
From the figure, we can conclude that the poles of the magnet are on either sides of the magnet
Therefore, options 1 and 2 are excluded
It is a convention that the magnetic field lines move out of the north pole of a magnet and into the south pole of the magnet
From the figure, we can see that the magnetic field lines are moving out from the right end and into the left end
This means that the north pole is at the right end and that the south pole is at the left one
What is the molarity of Na+ ions in a 0.02M sodium phosphate solution?
Answer:
.06 M NA+
Explanation:
You go from (.02M Na3PO4 / 1) x (3 mole Na+ / 1 mole Na3PO4) = .06 M Na+
If pOH of the compound equals to 2, it shows that compound is *
Strong basic
Strong acidic
Weak acidic
Weak basic
. Nếu dẫn 0,01 mol CO2 vào 50 ml dung dịch Ba(OH)2 0,1M thì sau phản ứng thuđược
A. BaCO3
B. Ba(HCO3)2
C. BaCO3 vàBa(HCO3)2
D. BaCO3 vàBa(OH)2
Name the method that used to separate the components of petroleum oil.
Answer:
fractional distillation
Explanation:
When pyridine is treated with a mixture of nitric and sulfuric acids, the major product is:.
Answer: 3-nitropyridine
Explanation:
discuss the solubility differences between the halogens and the halides in both hexane and water. be sure to define what a halogen and halide are to foundation your discussion.
Halides are ionic substances while halogens nonpolar substances. Hence, halides dissolves in water while halogens dissolve in hexane.
A halogen is an element in group seventeen. The name halogen means salt former. This name came about because many of the halogens form salts. Halides are salts formed by the halogens.
Halogens are diatomic covalent molecules. As such, they are nonpolar molecules and can only effectively interact with nonpolar solvents. Benzene is a nonpolar solvent hence it acts as an effective solvent for the halogens.
The halides are polar compounds hence they do not dissolve in nonpolar solvents such as hexane. Rather, halides dissolve in polar solvents such as water due to dipole - dipole interaction between the ions in the halide and the dipoles in water.
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fork is a metal or nonmetal ?
DO the postulates of daltons atomic theory explain the law of consrevetion of mass and thelaw of constant composition
Answer:
see answer
Explanation:
DO the postulates of Daltons atomic theory explain the law of conservation of mass and the law of constant composition.
Dalton's Atomic Theory Postulates1. Everything is composed of atoms, which are the indivisible building blocks of matter and cannot be destroyed or divided any further.
2. All atoms of a single pure element are the same in size and mass
3. Atoms of different elements vary from each other in size and mass.
4. Compounds are produced through different simple whole-number combinations of atoms to produce molecules.
5. Anywhere a compound exists, it will have the same atoms in the same ratio.
6. A chemical reaction between compounds is a re-arrangement of atoms
The law of conservation of mass is shown in 2, 4. and 5.
The law of constant co,position is shown in 2, 4, 5, and 6
Why are reforestation and reclamation important to environmental health?
Answer:
Reforestation can be used to undo and rectify the effects of deforestation and improve the quality of human life by absorbing pollution and dust from the air, rebuilding natural habitats and ecosystems,reducing global warming via biosequestration of atmospheric carbon dioxide, and harvesting for resources, particularly.
Explanation:
During secondary active transport, the movement of one substance down its electrochemical gradient provides the force to move another substance up its electrochemical gradient. When both substances move in the same direction the mechanism is referred to as a(n)
Given what we know about the mechanisms surrounding the biological movement of substances, we can confirm that when two substances in a secondary active transport move in the same direction, it is called a symport.
A secondary active transport harnesses the electrochemical energy generated by its movement of one substance, to aid the movement of the other. These movements can be of two types, depending on the directions:
AntiportSymportAn antiport transport will move both substances in opposite directions, meaning one out of the cell and one into the cell. The transport described in the question is that of a symport, given that it moves both substances in the same direction.
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What is required for two atoms to share electrons equally in a chemical bend?
Answer: Nonpolar Covalent Bond
Explanation: A Nonpolar Covalent Bond is created when atoms share their electrons equally. This usually occurs when two atoms have similar or the same electron affinity. The closer the values of their electron affinity, the stronger the attraction. This occurs in gas molecules; also known as diatomic elements.
What is the frequency of light with a wavelength of 450 nm?
Answer:
The frequency of blue light that has a wavelength of 450 nm is 6.7×1014 6.7 × 10 14 Hz.
Explanation:
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How many grams of acetic acid are present in 250g of vinegar that contains 5.00% acetic acid?
how many grams of magnesium cyanide would you need to add to 275 ml of water to make a 0.075 molal solution
The mass of magnesium cyanide needed to prepare the solution is 1.57 g
We'll begin by calculating the number of mole of Mg(CN)₂. This can be obtained as follow:
Volume = 275 mL = 275 / 1000 = 0.275 L
Molarity of Mg(CN)₂ = 0.075 M
Mole of Mg(CN)₂ =?Mole = Molarity x Volume
Mole of Mg(CN)₂ = 0.075 × 0.275
Mole of Mg(CN)₂ = 0.020625 mole
Finally, we shall determine the mass of Mg(CN)₂Mole of Mg(CN)₂ = 0.020625 mole
Molar mass of Mg(CN)₂ = 24 + 2(12 + 14) = 76 g/mol
Mass of Mg(CN)₂ =?Mass = mole × molar mass
Mass of Mg(CN)₂ = 0.020625 × 76
Mass of Mg(CN)₂ = 1.57 g
Therefore, 1.57 g of Mg(CN)₂ is needed to prepare the solution
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