This is very difficult

Answer:

  They are in the same family/group.

Explanation:

Both Ca and Sr are Group 2 elements, so can be expected to have similar chemical properties. Strontium would be expected to be chemically similar to calcium because they are in the same family/group.

Answer:

2200 g

Explanation:

Data Given:

no. of moles of Ba₃N₂ = 5 moles

mass of Ba₃N₂ = ?

Solution:

Formula used

            no. of moles = mass in grams / molar mass

To find mass rearrange the above equation:

mass in grams = no. of moles x molar mass. . . . . . (1)

molar mass of  Ba₃N₂

molar mass of  Ba₃N₂ = 3(137.3) + 2(14)

molar mass of  Ba₃N₂ = 412 + 28

molar mass of  Ba₃N₂ = 440 g/mol

Put values in equation 1

         mass in grams = 5 moles x 440 g/mol

         mass in grams = 2200 g

So,

mass of Ba₃N₂ = 2200 g

Answer: 28000m/s

Explanation:

Displacement = 700 km due north = 700000m

Time = 25secs

Velocity =?

Velocity = Displacement / Time

V = 700000 / 25 = 28000m/s

Answer:troposphere

Explanation:The troposphere is the layer that holds 80 percent of the total gas in the atmosphere.

Explanation:

Mixtures

They are formed when two or more substances are simply mixed in any ratio not chemically combined with each other.  

Characteristics  

Let us discuss few techniques :

1. Evaporation

For example :To obtain colored component (Dye) from Ink

Materials Required : Watch glass ink (blue/ black) beaker , stand, burner.  

Procedure :  

Observation:  

Evaporation taking place from the watch glass can be seen  

Residue is left on the watch glass  

Conclusion drawn :

2, Centrifugal method

 For example : To separate cream from milk by using centrifuge method.  

Materials Required : Full cream milk centrifuging machine/milk churner, jug test-tubes.  

Procedure:  

Observation

Cream floating on the milk can be seen.  

Conclusion drawn

When milk is rotated at high speed then the suspended lighter particles (fats and protein molecules) bind with each other forming ‘cream’ and ‘skimmed milk’. The cream being lighter floats over the skimmed milk which can be removed easily.  

3. Sublimation

For example :To separate a mixture of common salt and ammonium chloride :  

Materials Required : China dish, tripod stand mixture of common salt and ammonium chloride glass funnel cotton and burner.  

Procedure:  

Observation :  

Conclusion drawn: Ammonium chloride, being a volatile substance , changes into white vapors easily which deposits on the cold inner wall of the funnel. This ammonium chloride obtained is called the  

Answer:

45.4 g

Explanation:

Data given:

mole of oxygen = 1.26 mol

mass of water = ?

Reaction Given:

     2H₂ (g) + O₂(g) --------> 2H₂O (g)

Solution:

To solve this problem we look for mole mole ratio oxygen to water we look for the chemical reaction

                    2H₂ (g) + O₂(g)   ---------->  2H₂O (g)

                                    1 mole                  2 mol

So,

It is clear from the reaction that 1 mole oxygen gives 2 mole water then how many mole of water will produce by 1.26 moles of oxygen.

So apply unity formula

               2 moles H₂O ≅ 1 mole O₂

               X moles H₂O ≅ 1.26 mole O₂

Do cross multiplication

              X moles H₂O = 2 mol x 1.26 mole / 1 mole

              X moles H₂O ≅ 2.52 mol

So,

1.26 mole of oxygen produce 2.52 mole of water.

Now convert moles of water to mass

Formula will be used

      mass in grams = no. of moles x molar mass

molar mass of water (H₂O)

molar mass of H₂O = 2(1) + 16

molar mass of H₂O = 2 + 16 = 18 g/mol

put value in above equation:

           mass in grams = 2.52 mole x 18 g/mol

           mass in grams = 45.4 g

So,

1.26 moles oxygen produce 45.4 g water

Answer:

write down the number of atoms in each element, which is listed in the subscript next to each atom. Then, add coefficients to the atoms on each side of the equation to balance them with the same atoms on the other side.

Explanation:

Final answer:

To balance a chemical equation, write the correct formulas, count the atoms of each element, adjust coefficients to balance the atoms, use polyatomic ions as units, eliminate fractional coefficients for whole numbers, and check that all elements are balanced.

Explanation:

To balance a chemical reaction, one must ensure that the number of atoms for each element is equal on both sides of the equation. This is key to upholding the law of conservation of mass. The following steps are a simplified guide:

Write the skeleton equation with the correct formulas for reactants and products.

Count the number of atoms of each element in the reactants and in the products.

If the equation is not balanced, adjust the coefficients before the formulas, not the subscripts within them, to balance the atoms of each element.

Balance polyatomic ions as a unit if they appear unchanged on both sides of the equation.

Use fractional coefficients if necessary, and then multiply the entire equation to eliminate fractions and have whole number coefficients.

Perform a final check to ensure that all elements are balanced.

Throughout this process, one may use a trial-and-error approach to fine-tune the balancing, adjusting coefficients as needed until the number of atoms for each element is the same on both sides of the equation.

Answer:

(NH₄)₂SO₃

Explanation:

Data Given:

formula for "ammonium sulfite”

Solution

Ammonium sulfite consist of following atoms

Nitrogen = N

Hydrogen = H

Sulfur = S

Oxygen = O

Now we will look for the symbols of ammonium and sulfite

Ammonium = NH₄⁺

ammonium consists one nitrogen and 4 hydrogen atoms. it have overall 1 positive charge.

Sulfite = SO₃²⁻

it have one sulfur and 2 oxygen atoms. the overall charge is 2-.

Now we will write Both ammonium and sulfite ions together. the charges will are the combining power and will be written at the base of the alternate position formula unit.

      (NH₄)₂SO₃

So 2 ammonium ions combine with one sulfite ion.

So the formula for “ammonium sulfite” is (NH₄)₂SO₃

The formula of compound that shows the types and numbers of atoms present in a molecule of the compound ammonium sulfite is (NH₄)₂SO₃.

The formula of a compound is a chemical shorthand that provides information about the composition of the compound. The formula typically consists of the atomic symbols of the elements present in the compound, along with subscript numbers indicating the number of atoms of each element.

For example, the formula of water is H₂O, which indicates that it contains two hydrogen (H) atoms and one oxygen (O) atom. Similarly, the formula of sodium chloride is NaCl, representing one sodium (Na) atom and one chlorine (Cl) atom.

The formula of a compound is essential for understanding its chemical properties, stoichiometry, and reactions. It provides a concise way to represent the arrangement of atoms in a molecule and allows scientists to communicate and work with compounds more efficiently.

Learn more about Formula of compound, here:

https://brainly.com/question/32900415

#SPJ6

Explanation:

Green house effect

It can be explained as :

Answer:

Scientific investigation aims to design and implement an experiment to learn new information, where

development aims to design a product to solve a problem.

Explanation:

Answer:

D

Explanation:

Scientific investigation aims to design and implement an experiment to learn new information, whereas technological development aims to design a product to solve a problem.

Answer:

4. The blood vessels in their neck bulge out.  

Explanation:

This option is closest to being correct.

On Earth, the force of gravity pulls blood to the lower body. In space, the force of gravity is cancelled, so the blood spreads out evenly.

More blood in the upper body leads to increased blood pressure there, so the blood vessels in the neck bulge out.

The heart does not pump more blood per beat. Instead, it becomes lazy because it does not have to do as much work pumping blood back from the legs against the force of gravity.

A and B are wrong. You don't gain or lose blood simply by going into space.

C is wrong. The blood vessels in the neck bulge out.

The blood vessels in their neck bulge out because the heart pumps more blood per beat most likely happens when astronauts go to space.

In microgravity, the heart transforms from an elliptical shape (like a balloon filled with water) to a round sphere (a balloon filled with air), and the universe causes atrophy of the muscles that work on Earth and blood vessels. Shrinks. Nor can it control blood flow.

There are completely different results in the universe. There is no gravity that draws blood into the lower body. Instead, blood flows into the chest and head, the astronaut's face swells, and the blood vessels in the neck swell. And appearance isn't the only ugly side effect.

Learn more about astronauts blood vessels here: https://brainly.com/question/3975539

#SPJ2

Answer:

Dusting for fingerprints makes use of the physical property of stickiness. Skin oils absorb the fingerprint dust, which is then collected on a sticky tape.

Dusting for fingerprints makes advantage of stickiness as a physical change. Skin oils adsorb the dust from fingerprints.

Physical modifications are those that modify a chemical substance's shape but not its chemical content. Physical changes are normally unable to divide compounds into chemical elements or simpler compounds, although they can be utilized to separate mixtures into their  components.

A physical change happens when a substance's physical characteristics change without undergoing chemical composition. Melting, changes in size, volume, color, and crystal shape are examples of common physical changes.

Thus, the dusting for fingerprints makes advantage of stickiness as a physical change. Skin oils adsorb the dust from fingerprints.

To learn more about physical change follow the link;

https://brainly.com/question/3680148

#SPJ2

Answer: 4.07x 10²⁴ atoms Pb( SO4)2

Explanation: Solution:

6.755 moles Pb(SO4)2 x 6.022x10²³ atoms Pb(SO4)2 / 1 mole Pb(SO4)2

= 4.07x10²⁴ atoms Pb(SO4)2

Answer: Evaporation of salt water

Explanation: During the process of evaporating salt water which involves simple distillation, pure water is separated with salt molecules.

When heated water evaporates from the solution since it is less dense. When condensed it becomes pure water and salt is left out since it is more denser.

Answer:

Jöns Jakob Berzellus _

Invented the chemical notation system

Explanation:

Meaning of chemical notation : It is the representation of chemical composition of element by symbols.

Berzelius was the first person to measure accurate atomic weight of the elements, which helped to confirm Dalton's Atomic Theory.

He described how chemical bonds are formed by electrostatic attraction.

Berzelius, work with atomic weight and his theory of electrochemical dualism led to the development of Chemical notation that decide the chemical notation of the compounds.This chemical notation determines about the element both qualitatively and quantitatively.

He identified that compounds can be distinguished by the opposing constituents which are the acidic constituent , the basic and the neutral part.

This formula representation is given by Berzelius.

Answer:

Jöns Jakob Berzellus

Invented the chemical notation system

Explanation:

I got this one right on my test so it is right.

Answer:

The atom will have a negative charge.

Explanation:

Electrons are subatomic particles with a negative charge, protons are subatomic particles with a negative charge, and neutrons have no charge. When a neutral atom's balance is disrupted by an extra electron, the atom  becomes negatively charged.

Answer:

it will have a negative charge

Explanation:

Answer:

D) C4H 12 + 70 2 - 6H 20 + 4CO 2

Explanation:

I'm certain this is a combustion reaction.

Answer:

Helium has the highest First Ionization Energy in the Noble Gases group. Ionisation energy is the energy required to remove one mole of electrons from one mole of gaseous atoms.

Final answer:

Helium (He) has the highest first ionization energy among the noble gases, attributed to its stable valence shell configuration and minimal electron shielding effect.

Explanation:

The noble gas with the highest first ionization energy is Helium (He). This can be understood considering the general trend that ionization energy increases as one moves across a period from left to right in the periodic table. Noble gases, situated at the far right of the periodic table, consequently have the highest ionization energies within their respective periods due to their stable electronic configurations, with filled valence shells.

Among the noble gases, Helium, being the lightest and having the least number of electron shells, demonstrates the least shielding effect. This results in its valence electrons being more strongly attracted to the nucleus compared to other noble gases, thereby requiring more energy to remove an electron, i.e., higher ionization energy. In contrast, heavier noble gases like Xenon (Xe) and Radon (Rn) exhibit relatively lower first ionization energies due to increased electron shielding from inner electrons.

Answer:

2Na + MgF₂   → 2NaF  + Mg

Explanation:

Chemical equation:

Na + MgF₂   →  NaF  + Mg

Chemical equation:

2Na + MgF₂   → 2NaF  + Mg

The given reaction follow the law of conservation of mass because there are equal number of atoms of sodium, magnesium and fluorine are present on both side of equation.

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by french chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

Type of reaction:

The given chemical reaction is type of single replacement reaction. Sodium replace the magnesium and form sodium fluoride.

Single replacement:

It is the reaction in which one elements replace the other element in compound.

AB + C → AC + B

Answer:

Number of Moles = Reacting mass / Molecular mass

                              = 63.8 / 100.09

                              = 0.637g

Hence, the moles of calcium carbonate  in 63.8 g of calcium carbonate is 0.637g

Explanation:

The number of moles of a compound is the ratio of weight given to the molar mass. One mole calcium carbonate is 100.09 g/mol. Then, the number of moles in 63.8 g of calcium carbonate is 0.638 moles.

One mole of a substance is its amount containing 6.02 × 10²³ number of its  atoms. This number is called Avogadro number. Hence, one mole of any element contains Avogadro number of atoms. The mass of one mole of an element is called atomic mass.

Similarly one mole of any compound contains Avogadro number of molecules. The mass of one mole of the compound is called its molar mass.

Molar mass of calcium carbonate = 100.9 g/mol

given mass = 63.8 g

then, number of moles = 63.8 /100.9 g = 0.693 moles.

Therefore, the number of moles of 63.8 g of calcium carbonate is 0.693 moles.

Find more on number of moles:

https://brainly.com/question/12513822

#SPJ2

Answer:

Metaphase

prophase

anaphase

telophase

Explanation:

Answer: 0.19mol

Explanation

Mass of Ca = 7.6g

Molar Mass of Ca = 40g/mol

n = Mass /Molar Mass = 7.6/40

n = 0.19mol

Answer:

2.255 x 10²³ g

Explanation:

Data Given:

no. of molecules of BeO = 5.43 x 10⁴⁵ molecules

mass of BeO = ?

Solution:

first we will find no. of moles

Formula used

       no. of moles = no. of molecules / Avogadro's number

Where

Avogadro's number = 6.022 x 10²³

Put values in above equation

    no. of moles = 5.43 x 10⁴⁵ molecules / 6.022 x 10²³ (molecules/mol)

    no. of moles = 9.02 x 10²¹ mol

So,

There are 9.02 x 10²¹  moles of BeO of 5.43x10⁴⁵

Now we will find the mass

For this formula will be used

            No. of moles = Mass in grams/ molar mass

Rearrange the above equation

           mass in grams = no. of moles x molar mass . . . . . (1)

molar mass of BeO = 9 + 16 = 25 g/mol

Put values in equation 1

          mass in grams = 9.02 x 10²¹  moles x 25 g/mol

          mass in grams = 2.255 x 10²³ g

So,

Mass of 5.43 x 10⁴⁵ molecules of BeO = 2.255 x 10²³ g

The mass of 5.43x10^45 molecules of BeO can be calculated using the atomic masses provided in Appendix A.

The mass of 5.43x10^45 molecules of BeO can be calculated using the atomic masses provided in Appendix A. The atomic mass of BeO is given by the formula BE = {[2m(^1H) + 2mn] - m(ª X)}c². We can substitute the atomic masses of ^1H (1.007825 u) and mn (1.008665 u) into the formula to calculate the binding energy (BE). By rearranging the formula, we can solve for the mass of 5.43x10^45 molecules of BeO.

Answer: D

The correct way of writing a vector is to put a bar (-) on it.

Acceleration usually has the symbol a. It is a vector. The correct way

to write the symbol to show that it is a vector is  â. Option A is correct.

Acceleration refer to the rate of change of velocity with time. That is velocity divided by time.

Uniformly accelerated motion refer to the movement of velocity in a straight line and when the amount increase in velocity is in equal interval with amount increase in time.

Vector quantity is the quantity that have both magnitude and direction. Example include acceleration.

Scalar quantity refer to quantity with magnitude and no direction.

To know more about acceleration here

https://brainly.com/question/23919575

#SPJ2

Answer:

It should be gas.

Explanation:

It should be gas but I don't see the simulation so it's possible that it's solid/liquid

Answer:

12.6 gram of HF will produced 0.315 moles of SnF₂

Explanation:

Given data:

Mass of HF = 12.6 g

Moles of Tin fluoride produced = ?

Solution:

Chemical equation:

Sn + 2HF   →   SnF₂ + H₂

Number of moles of HF:

Number of moles = mass/ molar mass

Number of moles = 12.6 g/20.01 g/mol

Number of moles = 0.63 mol

Now we will compare the moles of HF with SnF₂.

                           HF            :               SnF₂

                            2             :                 1

                          0.63         :             1/2×0.63 = 0.315 mol

So 12.6 gram of HF will produced 0.315 moles of SnF₂.

Answer:

OH⁻ = 1.05×10⁻¹³ M

Explanation:

Given data;

H₃O⁺ = 9.61×10⁻² M

OH⁻ = ?

Solution:

First of all we will calculate the pH.

pH = -log [H⁺]

pH = -log [H₃O⁺]

Because pH is also the hydronium ion concentration.

pH = -log [ 9.61×10⁻²]

pH = 1.02

It is known that,

pH + pOH = 14

1.02 + pOH = 14

pOH = 14 - 1.02

pOH = 12.98

Concentration of OH⁻.

pOH = -log [OH⁻]

12.98 =  -log [OH⁻]

OH⁻ = 10∧-12.98

OH⁻ = 1.05×10⁻¹³ M

Answer:

Ca: [Ar] 4s²

Pm : [Xe} 6s² 4f⁵

Explanation:

The electronic configuation of an element in noble gas notation is written by giving the symbol of the nearest noble gas that is present in the period above it in the periodic table, followed by the electronic configuration of the remaining electrons.

For Ca the atomic no is 20

It is in 4th period.

The electronic configuration of Ca is 1s²2s²2p⁶3s²3p⁶4s²

1s²2s²2p⁶3s²3p⁶ represents the electronic congiguation of Ar with completely filled valence shell. So we can represent electronic configuration of Ca as [Ar] 4s².

The atomic no. of Promethium,Pm is 61. It's electronic configuration is

1s²2s²2p⁶3s²3p⁶4s² 3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f⁵

1s²2s²2p⁶3s²3p⁶4s² 3d¹⁰4p⁶5s²4d¹⁰5p⁶ is the configuration of the noble gas Xe . So we can represent electronic configuration of Pm as

[Xe} 6s² 4f⁵

Answer:

Ca: [Ar] 4s²

Pm : [Xe} 6s² 4f⁵

Explanation: