A change that occurs when a solid melts or a liquid freezes is an example of a _____ change.

A. chemical
B. phase
C. oxidation
D. molecular

There are many gases in the atmosphere, that are harmful. Out of all gases carbon dioxide is the one.  By plantation we can decrease the amount of carbon in atmosphere.

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.

Carbon is release in large quantity around us on burning of fuels form of carbon dioxide. Carbon in our atmosphere is not good for us . So there is need to decrease the amount of carbon in atmosphere. The only way to decrease the amount of carbon in atmosphere is by increase plantantion.

Therefore, by plantantion we can decrease the amount of carbon in atmosphere.

To know more about element, here:

https://brainly.com/question/8460633

#SPJ5

To contain the same number of atoms also mean to contain the same number of moles. So let us say that X is the mass of Silver Ag required, so that:

X / 107.87 = 10 / 10.81

X = 99.79 g

Answer: The mass of silver atoms is 99.78 grams.

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]      .....(1)

For boron:

Given mass of boron = 10.0 g

Molar mass of boron = 10.81 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of boron}=\frac{10.0g}{10.81g/mol}=0.925mol[/tex]

As, the number of atoms of silver are same as the number of atoms of boron. This means that number of moles of boron will be same as number of moles of silver.

Now, calculating the mass of silver atoms by using equation 1, we get:

Molar mass of silver = 107.87 g/mol

Moles of silver = 0.925 moles

Putting values in equation 1, we get:

[tex]0.925mol=\frac{\text{Mass of silver}}{107.87g/mol}\\\\\text{Mass of silver}=99.78g[/tex]

Hence, the mass of silver atoms is 99.78 grams.

There are 0.538 moles of ¹³C atoms in the given 7.00 g sample.

This is a simple mole conversion problem.  It requires the molar mass, or the mass of one mole of a substance, of carbon - 13, an isotope of carbon. An isotope is like a different version of a specific atom. In this case, carbon - 13 is a version of a carbon atom that has one more neutron than the normal carbon atom. It is a little heavier than the normal carbon atom because of its extra neutron.

To convert from grams of sample to moles of sample, the general equation is:

[tex]moles \ of \ sample = \frac{given \ mass}{molar \ mass}[/tex]

To convert 7.00 g of ¹³C, the equation is:

[tex]mole \ of \ ^{13}C \ = \frac{7.00 \ g}{13.00 \ \frac{g}{mol}} \\\boxed {mole \ of \ ^{13}C \ = 0.53846 \ mol}[/tex]

Since there is only 3 significant figures in the given, the final answer must also have 3 significant figures. Therefore,

[tex]\boxed {\boxed {mole \ of \ ^{13}C \ = 0.538 \ mol \ or \ 5.38 \times 10^{-1} \ mol}}[/tex]

This answer is logical since one mole of ¹³C will have a mass of 13.00 g. The given sample (7.00 g) is less than 13.00 g so the mole equivalent of that should be less than one mole.

The man who created the original version of the modern Periodic Table of Elements is no other than Dmitri Mendeleev (1834 – 1907). He was a Russian chemist and inventor. Taken from his name, the element Mendelevium (symbol Md, atomic number 101) is named to him in his honor.

Answer:

 Mendelevium (Md)

Mendelevium, with atomic number 101, is named after Dmitri Mendeleev who created the first periodic table and arranged elements predicting future discoveries.

The element named after Dmitri Mendeleev, the man credited with creating the first periodic table, is called mendelevium. With an atomic number of 101, mendelevium was synthesized in 1955, which was several years after Mendeleev's death. Mendeleev's table arranged elements by atomic mass and left spaces for undiscovered elements, which showed his predictive insight into the chemical properties of elements. His version of the periodic table was significant due to its ability to predict new elements and their properties.

the answer is c, the number of protons plus the number of neutrons in a nucleus

Final answer:

The boiling point of water is 100°C and is an intensive property because it does not change with the amount of water. Intensive properties do not vary with the quantity of substance, while extensive properties do.

Explanation:

The boiling point of a substance is the temperature at which it changes from a liquid to a gas. For water, this temperature is 100°C under standard atmospheric pressure (1 atm). Whether we have 250 ml or 1000 ml of water, the boiling point remains the same and is an example of an intensive property. This is because intensive properties do not depend on the amount of substance present.

Regarding extensive and intensive properties, temperature is an example of an intensive property because it does not change when the amount of substance is doubled. On the other hand, an extensive property is dependent on the amount of substance (e.g., volume or mass). Combining two samples of water with the same temperature will result in a mixture of the same temperature, demonstrating that temperature is intensive.

When considering the ratio of two extensive properties, such as mass to volume to obtain density, the resultant property is intensive because it characterizes the property per unit amount, therefore not changing with the quantity of substance.

Equilibrium

We are given that there are 2 moles of NO3 from the 0.225 M Sr(NO3)2 solution. Therefore we simply use stoichiometry to solve this problem.

Concentration NO3 = 0.225 M Sr(NO3)2 * (2 moles NO3 / 1 mole Sr(NO3)2)

Concentration NO3 = 0.45 M

Answer : The concentration of nitrate ions is 0.450 m.

Solution : Given,

Molarity of [tex]Sr(NO_3)_2[/tex] = 0.225 m

The balanced ionic equation is,

[tex]Sr(NO_3)_2\rightarrow Sr^{+2}+2NO^-_3[/tex]

From the reaction, we conclude that the 1 mole of [tex]Sr(NO_3)_2[/tex] produces 2 moles of [tex]NO^-_3[/tex] ions. That means the concentration of nitrate ions is twice the value of [tex]Sr(NO_3)_2[/tex].

then, 0.225 m of [tex]Sr(NO_3)_2[/tex] gives 2 × 0.225 of [tex]NO^-_3[/tex] ions

Now the concentration of [tex]NO^-_3[/tex] ions is equal to 0.450 m.

Answer:

a just took the test on engenuity

Explanation:

hope dis helps : p

California’s rice fields are visited by migrating waterfowl. Hence option a is correct.

Migration is defined as movement from one nation, location, or neighborhood to another in quest of greater chances for settling. The primary beneficial consequences of migration on host countries are the growth of the labor force, the diversification of cultures, the filling of skill gaps in the labor market, and the improvement of local economies. Differences in income and economic opportunities between nations, varied levels of social and human security, and preexisting ethnic and diaspora networks are the main drivers of international migration.

Waterfowl are birds with waterproof feathers and webbed feet that can swim well. They propel themselves through the water by using their webbed feet as flippers. Waterfowl frequently have webbed feet, rounded bodies, long necks, and short wings. Near water bodies, waterfowl typically build their nests on the ground. Some are an exception to this rule, such as the Common Merganser and Wood Duck, which lay their eggs in nest boxes or cavities in trees.

Thus, California’s rice fields are visited by migrating waterfowl. Hence option a is correct.

To learn more about migration, refer to the link below:

https://brainly.com/question/28827966

#SPJ6

Final answer:

The bond length in[tex]F_{2}[/tex] is shorter than expected due to electron-electron repulsion and the influence of molecular orbitals, which lead to a bond length that doesn't simply equate to twice the atomic radius of fluorine.

Explanation:

The bond length in [tex]F_{2}[/tex] is shorter than twice the atomic radius of F because of electron-electron repulsion within the molecule. The process of bond formation involves not just the attraction between the electrons and nuclei but also the repulsion between the nuclei themselves and the electron pairs. When two fluorine atoms approach each other, their unpaired electrons in their outermost shells pair up to form a covalent bond, and due to fluorine's high electronegativity and small size, there is significant repulsion between these electrons when they are in close proximity. Additionally, when considering bond lengths, it is important to note that molecular orbital theory and experimental data both play a role in understanding the nature of bonds. The molecular orbital theory, which considers both bonding and antibonding orbitals, predicts a single bond for [tex]F_{2}[/tex]  as confirmed by the experimental bond order. Therefore, the combination of these repulsive forces and the nature of the molecular orbitals involved results in a bond length that is shorter than the sum of two fluorine atomic radii.

A substance and a solution are similar in that they both consist of matter composed of atoms, ions, or molecules, but they differ in that a substance refers to any specific type of matter, while a solution is a specific type of mixture that consists of a solvent and a solute.

A substance and a solution are similar in that they both consist of matter composed of atoms, ions, or molecules. They are different in that a substance refers to any specific type of matter, while a solution is a specific type of mixture that consists of a solvent and a solute. Solutions are homogeneous mixtures, meaning that the solute molecules are distributed evenly throughout the solvent. For example, when you dissolve sugar in water, the sugar molecules are separated by water molecules and evenly distributed throughout the solution.

https://brainly.com/question/30587659

#SPJ11

The formula for Barium nitrite is Ba(NO₂)₂. This is because barium has a +2 charge and nitrite has a -1 charge, so two nitrite ions are needed to balance the charge of the barium ion. So correct option is a.

a) Ba(NO₂)₂.

Barium nitrite is a chemical compound formed by the combination of the elements barium (Ba) and nitrite (NO₂). To understand the formula of barium nitrite, let's break down the composition of the compound:

1. Barium (Ba):

Barium is a metallic element with the chemical symbol "Ba." It belongs to the alkaline earth metal group, which is located in group 2 of the periodic table. Barium is a highly reactive metal that readily forms compounds with other elements.

2. Nitrite (NO₂):

Nitrite is a polyatomic ion composed of one nitrogen atom (N) and two oxygen atoms (O). Its chemical formula is NO₂. Nitrite is negatively charged due to the presence of two extra electrons, which gives it a -1 charge.

The chemical formula of barium nitrite is Ba(NO₂)₂.

To know more about barium nitrite here

https://brainly.com/question/30226594

#SPJ6

To count atoms in 4 HNO3, the coefficient 4 is multiplied with the number of each type of atom. It results in 4 hydrogen atoms, 4 nitrogen atoms, and 12 oxygen atoms.

To count atoms in a chemical formula like 4 HNO3, you look at the coefficients and subscripts. The coefficient (4 in this case) tells us how many molecules of HNO3 there are. We multiply this by the number of each type of atom within one molecule. Nitric acid (HNO3) has one hydrogen (H), one nitrogen (N), and three oxygen (O) atoms. Therefore, to count the atoms in 4 HNO3, we do the following: 4 molecules of HNO3 each contain 1 H atom, giving us a total of 4 H atoms; 4 molecules have 1 N atom each which is a total of 4 N atoms; and 4 molecules each have 3 O atoms, resulting in 12 O atoms in total. So, 4 HNO3 contains 4 hydrogen atoms, 4 nitrogen atoms, and 12 oxygen atoms.

Magnesium combines with oxygen to form magnesium oxide, which is characterized by the chemical formula MgO. The reaction is facilitated by the burning of magnesium in the presence of oxygen. This reaction highlights magnesium's strong affinity for oxygen.

The element from the periodic table that combines with oxygen to form magnesium oxide is magnesium. This is derived from the chemical formula for magnesium oxide, which is MgO. Here, Mg represents magnesium and O represents oxygen. The reaction to create magnesium oxide typically occurs when magnesium is burnt in the presence of oxygen, as illustrated by the chemical reaction: 2Mg(s) + O₂(g) → 2MgO(s). This reaction shows that magnesium and oxygen combine to form magnesium oxide.

Magnesium is recognized for its potency in chemical reactions, particularly in those involving oxides. When magnesium burns, it reacts with carbon dioxide to produce elemental carbon, demonstrating magnesium's significant affinity for oxygen.

Moreover, many of the common salts of the alkaline earth metals like magnesium are insoluble in water due to their high lattice energies and these compounds' divalent metal ions.

https://brainly.com/question/29828193

#SPJ2

Answer:

Explanation:

The option A, B and C are true statement while D is false statement.

Mass remains constant.

Only the form changes.

Kinetic energy changes.

Something new is formed.

CaCO3(s) ⟶ CaO(s)+CO2(s) 

moles CaCO3: 1.31 g/100 g/mole CaCO3= 0.0131 

From stoichiometry, 1 mole of CO2 is formed per 1 mole CaCO3, therefore 0.0131 moles CO2 should also be formed. 
0.0131 moles CO2 x 44 g/mole CO2 = 0.576 g CO2 

Therefore:
% Yield: 0.53/.576 x100= 92 percent yield

Answer : The percent yield for this reaction is, 91.9 %

Solution : Given,

Mass of carbon dioxide = 0.53 g

Mass of calcium carbonate = 1.31 g

Molar mass of carbon dioxide = 44 g/mole

Molar mass of calcium carbonate = 100 g/mole

First we have to calculate the moles of [tex]CaCO_3[/tex].

[tex]\text{Moles of }CaCO_3=\frac{\text{Mass of }CaCO_3}{\text{Molar mass of }CaCO_3}=\frac{1.31g}{100g/mole}=0.0131moles[/tex]

Now we have to calculate the mass of carbon dioxide.

The balanced chemical reaction is,

[tex]CaCO_3(s)\rightarrow CaO(s)+CO_2(g)[/tex]

From the balanced reaction we conclude that

As, 1 mole of [tex]CaCO_3[/tex] react to give 1 mole of [tex]CO_2[/tex]

So, 0.0131 mole of [tex]CaCO_3[/tex] react to give 0.0131 mole of [tex]CO_2[/tex]

Now we have to calculate the mass of carbon dioxide.

[tex]\text{Mass of }CO_2=\text{Moles of }CO_2\times \text{Molar mass of }CO_2[/tex]

[tex]\text{Mass of }CO_2=(0.0131mole)\times (44g/mole)=0.5764g[/tex]

Now we have to calculate the percent yield for this reaction.

[tex]\%\text{ yield of }CO_2=\frac{\text{Actual yield of }CO_2}{\text{Theoretical yield of }CO_2}\times 100=\frac{0.53g}{0.5764g}\times 100=91.9\%[/tex]

Therefore, the percent yield for this reaction is, 91.9 %