True or false A recent investigation found relatively high levels of the metalloid
arsenic in samples of apple juice. This would not be harmful
because arsenic is a stable metalloid.

Answer:

The skin of the apple is very thin, and the crust of the Earth is very thin.

Answer:

SF4 -Covalent bond

BaBr2 - Ionic bond

Ca - Metallic bond

Explanation:

Sulphur and fluorine are non metals. Nonmetal atoms combine by the sharing of electrons. This is also called a covalent combination(bond).

In BaBr2, a metal is combined with a nonmetal. This combination involves a transfer of electrons from the metal to the nonmetal forming an ion pair. This is otherwise called an ionic bond.

Atoms of a metal are held together by strong metallic bonds that involves positively charged cations and a cloud of electrons.

Answer: [tex]Co+2Na_2S\rightarrow 4Na+CoS_2[/tex]

Explanation:

According to law of conservation of mass, mass can neither be created nor be destroyed. The atoms on the reactant side must be equal to the number of atoms on the product side so that the mass remains the same on reactant and product side. Thus the reactions are balanced.

Single displacement reaction is one where a more reactive element replaces the lesser reactive one.

The balanced chemical reaction will be:

[tex]Co+2Na_2S\rightarrow 4Na+CoS_2[/tex]

Answer:

I think qs. "A" the net force acting on the book by gravity is down..

The statement is "The net force acting on the book by gravity is down."

Gravity is defined as the force that pulls materials toward the center point of a planet or other entity.

The textbook falls to the ground because of gravitational attraction between the ground and the book.

Because of the Earth's gravitational influence, the textbook moves towards the Earth when nothing is keeping it up. We know that the book has an equivalent impact on the Earth.

With a free fall acceleration of g, the textbook accelerates toward the Earth.

Hence, the correct option is A

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Answer:

For 1 mole of MgCl2, it would require 2 moles of KOH. ( 1 : 2 mole ratio)

Since you have 3 moles of KOH, it is in excess, and MgCl2 is the limiting reactant.

It attempts to explain the idea that:C. energy is quantized

Answer:

6.) mixture

8.) compound

Answer:

58.3%

Explanation:

The formula of the compound is given as:

     CsPO₄  

Now, the percentage composition of Cs in the compound is = ?

So;

To find this parameter, find the molar mass of the compound:

  Molar mass of  CsPO₄   = 132.9 + 31 + 4(16)  = 227.9g/mol

Percentage composition of Cs= [tex]\frac{132.9}{227.9} x 100[/tex]   = 58.3%

Answer:

159571 lb or cubic feet

Explanation:

Answer:

Between carbon and silicon, silicon element has the strongest attraction between its nucleus and its valence electrons.

because silicon's nucleus is bigger than carbon.silicon loses electrons easily than carbon.

Answer:

B. Carbon shares 2 pair of electrons with each oxygen.

Explanation:

Hope it helped!

Answer:

The electrochemical phenomenon of rusting of iron can be described as : At Anode: Fe (s) undergoes oxidation to releases electrons. Electrons released at anode move to another metal and reduce oxygen in presence of H+. It is available from H2CO3 formed from the dissolution of CO2 from air into water.

Answer:

The chemistry of iron is dominated by the +2 and +3 oxidation states i.e. iron(II) and iron(III) complexes e.g. Fe2+ and Fe3+ complex ions with selected ligands, usually of an octahedral shape, a few tetrahedral iron(III) complexes are mentioned too. The reactions of the aqueous ions iron(II) and iron(III) with ammonia, sodium hydroxide and sodium carbonate are described and explained as are complexes of iron(III) with the chloride ion and cyanide ion.

principal oxidation states of iron, redox reactions of iron, ligand substitution displacement reactions of iron, balanced equations of iron chemistry, formula of iron complex ions, shapes colours of iron complexes, formula of compoundsExplanation:

Answer:

3.39 x 10²³ particles

6.02 x 10²²particles

Explanation:

The problem here entails we find the number of particles in the given substances.

From the mole concept;

          1 mole of a substance contains 6.02 x 10²³ particles

a. 18g of O₂;

 We first find the number of moles of this substance first;

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

  Molar mass of O₂   = 2(16) = 32g/mol

      Number of moles  = [tex]\frac{18}{32}[/tex]   = 0.56mole

 So;

             1 mole of a substance contains 6.02 x 10²³ particles

            0.56 mole of  O₂ will contain 0.56 x 6.02 x 10²³ particles

                                                                   = 3.39 x 10²³ particles

b. 0.1mole of calcium atom:

        1 mole of a substance contains 6.02 x 10²³ particles

       0.1 mole of the substance will contain 0.1 x  6.02 x 10²³ particles

                                                                         = 6.02 x 10²²particles

Answer:

18.65004 grams H2O

Explanation:

First, we need to write down the balanced chemical equation for the decomposition reaction:

2LiOH -> H2O + Li2O

Since we have grams of LiOH and we need to know the grams of water, we need to convert to moles since we can only compare moles to moles.

The amu of LiOH is 23.947.

The given grams of LiOH is 63.. To convert to moles, we will divide 63 by 23.947..

This gives us 2.6310 moles LiOH..

To convert to moles of H2O (and later grams of H2O), we will use the mole fractions from the balanced equation...

When we look at the balanced equation we can see that 2 moles of LIOH can produce 1 mol of Water, so:

2.6310 moles [tex]* \frac{1 molH_{2}O}{2 mol LiOH}[/tex] = 1.3155 moles H2O

Now we will convert from moles to grams (we must multiply by the amu)

1.3155 moles H2O = 18.65 grams H2O

According to stoichiometry of the chemical equation of decomposition of lithium hydroxide 23.6 g of water are produced from the decomposition of 63 grams of lithium hydroxide.

Stoichiometry is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.

Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.It is useful in balancing chemical equations.

In the given example, as 47.9 g of lithium hydroxide produces 18 g water ,therefore 63 of lithium hydroxide will produce 63×18/47.9=23.6 g of water.

Thus, 23.6 g of water are produced from the decomposition of 63 grams of lithium hydroxide.

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Given,

Mass of a rifle = 5.5 kg

Mass of a bullet = 11 g

Speed of a bullet = 1000 m/s

To find,

(a) The recoil velocity of the rifle.

(b) If the shooter holds the rifle firmly against his shoulder, What will be the recoil velocity.

Solution,

(a) Let v₁ is the recoil velocity of the rifle. We can use the conservation of momentum to find it. The momentum of the system will remains conserved.

[tex]m_1v_1=m_2v_2\\\\v_1=\dfrac{m_2v_2}{m_1}\\\\v_1=\dfrac{0.011\times 1000}{5.5}\\\\v_1=2\ m/s[/tex]

So, the recoil velocity of the rifle is 2 m/s and it is in opposite direction of he bullet.

(b) Let V is the recoil velocity if the shooter holds the rifle firmly against his shoulder. Again using the conservation of momentum.

[tex]V=\dfrac{0.011\times 1000}{120}\\\\v=0.091\ m/s[/tex]

Therefore, this is the required solution.

Answer:

2 [tex]\pi[/tex] r

Explanation:

Given that:

Radius of basketball  = 9inches

Unknown:

Hoop's circumference  = ?

Solution:

To solve this problem, we use the formula for the circumference of a circle.

The shape of the hoops is circular.

 Circumference of a circle = 2 [tex]\pi[/tex] r

R is the radius of the basketball hoop

Answer:

According to avogadro's law, 1 mole of every substance contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles and weighs equal to its molecular mass.

To calculate the moles, we use the equation:

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

[tex]\text{Number of moles}=\frac{\text{Given molecules}}{\text {Avogadros number}}[/tex]

a. moles in 14.08 g of [tex]C_{12}H_{22}O_{11}[/tex] = [tex]\frac{14.08g}{342.3g/mol}=0.04113moles[/tex]

molecules in 14.08 g of [tex]C_{12}H_{22}O_{11}[/tex] = [tex]0.04113\times 6.023\times 10^{23}=0.2477\times 10^{23}[/tex]

b. moles in 17.75 g of NaCl = [tex]\frac{17.75g}{58.5g/mol}=0.3034moles[/tex]

molecules in 17.75 g of [tex]NaCl[/tex] = [tex]0.3034\times 6.023\times 10^{23}=1.827\times 10^{23}[/tex]

formula units 17.75 g of [tex]NaCl[/tex] = [tex]0.3034\times 6.023\times 10^{23}=1.827\times 10^{23}[/tex]

c. moles in 20.06 g of  [tex]CuSO_4.5H_2O[/tex]= [tex]\frac{20.06g}{249.68g/mol}=0.08034moles[/tex]

formula units in 20.06 g of  [tex]CuSO_4.5H_2O[/tex]= [tex]0.08034\times 6.023\times 10^{23}=0.4839\times 10^{23}[/tex]

Answer:

Cumulus clouds look like fluffy, white cotton balls in the sky. Since they are so thin, they seldom produce much rain or snow.

Cumulonimbus clouds are menacing looking multi-level clouds, extending high into the sky in towers or plumes. More commonly known as thunderclouds, cumulonimbus is the only cloud type that can produce hail, thunder and lightning.

Nacreous clouds are some of the rarest clouds on the planet. They are a form of polar stratospheric cloud, which is a main culprit in chemical destruction of the ozone layer.

Explanation:

Answer:

Helium

Explanation:

He- 3.99739969150064 (4)

S-0.498986433806336 (0.5)

Li-3.02550064832148 (3)

B-2.959948200906496 (3)

Answer:

Saliva and teeth in this order

Explanation:

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Answer:

1254 J

Explanation:

Mass, m = 10.0g

Initial Temperature = 20°C

Final Temperature = 50°C

Energy = ?

Specific heat capacity, c = 4.18 J/g·°C

The relationship between these quantities is given by the equation;

H = mcΔT

ΔT = Final Temperature - Initial Temperature = 50 - 20  = 30 °C

H = 10 * 4.18 * 30

H = 1254 J

Answer:

Explanation:

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Answer:

Electromagnetic Radiation

Explanation:

When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object's material and the frequency (color) of the light. However, because light can travel through space, it cannot be a matter wave, like sound or water waves.

Answer:

It is called "periodic" because elements are lined up in cycles or periods. From left to right elements are lined up in rows based on their atomic number (the number of protons in their nucleus). ... Each horizontal row in the table is a period. There are seven (or eight) total periods.

Explanation:

Answer:

The formula unit for beryllium oxide is BeO

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Answer:

3CaSO₄  + 2AlCl₃ →  Al₂(SO₄)₃   +   3CaCl₂

Explanation:

The reaction expression is given as:

        _CaSO₄  + _AlCl₃ →  _Al₂(SO₄)₃   +   _CaCl₂

To balance the reaction above, let us a mathematical approach;

         assign coefficients a, b, c and d to the species;

       aCaSO₄  + bAlCl₃ →  cAl₂(SO₄)₃   +   dCaCl₂

Conserving Ca : a  = d  

                     S:  a = 3c

                     O:  4a  = 12c

                     Al:    b = 2c

                     Cl:   3b = 2d

So;

 let a = 1, d = 1, c   = [tex]\frac{1}{3}[/tex] , b  = [tex]\frac{2}{3}[/tex]  

  Multiply by 3 through;

 a = 3, b  = 2, c  = 1 and d  = 3

  3CaSO₄  + 2AlCl₃ →  Al₂(SO₄)₃   +   3CaCl₂