Where would a disease transmitted by person to person contact be most likely to spread quickly

Answer: Na, S, Cl

Explanation:

Atomic size decreases as one moves from left to right on the periodic table with elements in the same period. This is as a result of the electrons increasing in the outer circle and thus being drawn to the protons in the nucleus which will lead to the outer shell area decreasing.

Sodium (Na) comes before Sulfur (S) which comes before Chlorine (S) so this is the decreasing order as they are all in the same period.

Mostly and for what I would say is A

The gases can undergo compression when subjected to lower temperatures and pressure. The water bottle becomes dented as the collision slowed down and got closer to each other. Thus, option C is correct.

Freezing has been the physical process that is involved in changing the states of matter from liquid to solids. This results in a decrease in the entropy of the water which decreases the heat and randomness of the particles.

As the temperature decreases the collision and the kinetic energy of the particles decreases. This results in the loss of entropy and makes the molecules or the particles show a higher force of attraction leading to close packing. The space becomes dense and tightly packed.

As the particle becomes closely packed it dents the water bottle at low temperature as now it has its own shape (solids) unlike the liquids. The lower temperature converts the liquids into solids.

Therefore, as the water freezes the bottle experiences a dent as ice is formed from liquids by freezing.

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Answer:

2.5 moles of oxygen are produced.

Explanation:

Given data:

Number of moles of O₂ produced = ?

Number of moles of HgO decomposed = 5 mol

Solution:

Chemical equation:

2HgO      →     2Hg + O₂

now we will compare the moles of HgO and O₂.

           HgO         :          O₂

            2              :          1

            5              :         1/2×5 = 2.5

Thus, from 5 moles of HgO 2.5 moles of oxygen are produced.

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Answer:

Six Steps to Control Workplace Hazards

Step 1: Design or re-organise to eliminate hazards. ...

Step 2: Substitute the hazard with something safer. ...

Step 3: Isolate the hazard from people. ...

Step 4: Use engineering controls. ...

Step 5: Use administrative controls. ...

Step 6: Use Personal Protective Equipment (PPE)

Explanation:

i it true?

Answer:

2

Explanation:

Based on the chemical equation, the number of molecules of hydrogen gas in the reactant side is 2.

This is indicated by the coefficient before reactant.

A molecule is a covalent compound that has discrete or separate units.

So H₂ is made up of two atoms of hydrogen that has been covalently bonded together by sharing their valence electrons.

From the reaction expression:

   2 molecules of hydrogen gas combines with 1 molecule of oxygen gas to produce 2 molecules of water.

Answer:

Explanation:

if it has a lower density than the liquid it's in will float

Answer:

Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol

Explanation:

Activation energy decreases from = 56 kj/mol to 35 kj/mol

products = 78 KJ lower in energy than reactants

Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol

attached below are the sketches of approximate energy-level for both catalyzed and uncatalyzed reactions

Answer:

Average atomic mass  = 3.9 amu

Explanation:

Given data:

Percent abundance of He-2 = 0.420%

Percent abundance of He-3 = 2.75%

Percent abundance of He-4 = 96.83%

Average atomic mass = ?

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) + (abundance of 3rd isotope × its atomic mass)  / 100

Average atomic mass = (0.420×2)+(2.75×3) +(96.83×4)/100

Average atomic mass =  0.84 + 8.25 +387.32 / 100

Average atomic mass = 396.41 / 100

Average atomic mass  = 3.9 amu.

Answer:

Vibrational energies of atoms

Explanation:

Planck applied quantization to Vibrational energies of atoms because in Black body spectrum prediction a blackbody at equilibrium is expected to radiate energies at various Frequencies ( i.e. increase in radiated energy ∝ increase in frequency ) but towards the ultraviolet region of the spectrum the energy radiated begins to drop as frequency increases. The phenomenon of drop in energy with increase in frequency is termed Ultraviolet catastrophe. hence to solve this phenomenon Planck applied quantization to Vibrational energies of atoms

Answer:

the effluent concentration is 0.06236 mg/L

Explanation:

Given that;

treatment capacity [tex]V_{0}[/tex] = 3,800 m³/d =  ( 3,800 × 86.4) =  43.98 L/sec

reactor's volume V = 45 m³ = (45 × 1000) = 45,000 L

reaction rate constant K =  0.0125 s⁻¹

influent manganese concentration [tex]CA_{0}[/tex] = 0.86 mg/L

-[tex]r_{A}[/tex] = [tex]KC_{A}[/tex]

Now, performance equation for CSTR is expressed as follows;

[tex]\frac{V}{V_{0} }[/tex] = [tex]\frac{CA_{0} -CA _{} }{-r_{A} }[/tex]

[tex]\frac{V}{V_{0} }[/tex] = [tex]\frac{CA_{0} -CA _{} }{KC_{A} }[/tex]

So we substitute

45000L / 43.98 L/sec = ( 0.86 mg/L - CA) / 0.0125 CA

we cross multiply

562.5CA = 37.8228 - 43.98CA

562.5CA + 43.98CA = 37.8228

606.48CA = 37.8228

CA = 37.8228 / 606.48

CA = 0.06236 mg/L

Therefore, the effluent concentration is 0.06236 mg/L

Answer:

C. P = nRT

Explanation:

PV = nRT, where n is a number of moles and R is the universal gas constant, R = 8.31 J/mol ⋅ K.

Hope this helps :)

Answer:T =PV/nR

Explanation:

Answer:

Kindly check the attached picture for the diagram of the chemical compound.

Explanation:

So, the following parameters were given from the question above;

=> A triplet at 0.9 ppm and a quartet at 1.4 ppm, a singlet at 1.35 ppm. Now, the unknown compound has a molecular formula of C7H16O.

For a triplet at 0.9ppm, there are nine (9) atoms of hydrogen, for the quartet at 1.4ppm there are six(6) atoms of hydrogen and for the singlet at 1.35 ppm, the number of hydrogen atoms is one(1). Hence, the total number of hydrogen atoms = 16.

Therefore, number of bondings = [(2 × number of carbon atoms) + 2 - number of hydrogen atoms present on the compound)/2 .

Thus number of bonds =[( 2× 7) + 2 - 16] ÷ 2 = 0.

Hence, there is no double bond or ring in the compound.

Answer:

1. 0.74mol

2. 0.42mol

3. 2.125mol

4. 0.301mol

5. 4.52 × 10^23 particles

Explanation:

Number of moles (n) in a substance can be found using the formula:

mole (n) = mass/molar mass

Using this formula, the following moles are calculated:

1. Molar of Na = 23g/mol

mole = 17/23

mole = 0.74mol

2. Molar mass of Na2SO4 = 23(2) + 32 + 16(4)

= 46 + 32 + 64

= 142g/mol

Mole = 60/142

mole = 0.42mol

3. Molar mass of CO2 = 12 + 16(2)

= 12 + 32

= 44g/mol

mole = 93.5/44

mole = 2.125mol

4. Molar mass of sodium nitrate (NaNO3) = 23 + 14 + 16(3)

= 23 + 14 + 48

= 85g/mol

mole = 25.6/85

mole = 0.301mol

5. Number of particles in one mole of a substance is 6.022 × 10^23 particles. Hence, in 0.75mol of calcium hydroxide (Ca(OH)2, there will be;

0.75mol × 6.02 × 10^23

= 4.515 × 10^23

= 4.52 × 10^23 particles

Test tubes heat small amounts of liquids while boiling tube boils liquids

Answer:

Black

Explanation:

Answer:

the answer is

-there is the same number of each type of atom on the right side of the equation as the left.

Explanation:

i have study island too :')

Answer:

See explanation

Explanation:

Here we are trying to see how a binary covalent compound is named. A binary covalent compound comprises of only two elements held together by covalent bonds.

The first element retains its normal name whereas the second element has the suffix -ide added to it.

For instance, CO2 is named as carbon dioxide, HBr is named as hydrogen bromide etc.

Answer: it's ide

Explanation:

Got it right in the quiz

Answer:

See explanation and images attached

Explanation:

a) In the mechanism for the acid catalysed esterification of propanoic acid using ethanol, we can see that the first step is the protonation of the acid followed by nucleophillic attack of the alcohol. Loss of water and consequent deprotonation regenerates the acid catalyst. We can see the fate of the 18O labelled ethanol in the mechanism shown.

b)  In the second mechanism, an unnamed ester is hydrolysed using an acid catalyst. The attack of the acid and subsequent nucleophillic attack of water labelled with 18O leads to the incorporation of this 18O into the product acid as shown in the mechanism attached to this answer.

Answer:

37.4 mol.

Explanation:

Hello!

In this case, since the Avogadro's number help us to realize that one mole of any substance contains 6.022x10²³ formula units, in this case atoms of zinc, the following dimensional analysis provides the correct answer:

[tex]=2.25x10^{25} atoms*\frac{1mol}{6.022x10^{23}atoms}\\\\= 37.4mol[/tex]

Best regards!

Answer:

a. ((100 - 35)/100) times 5.5 grams = 3.575 g

Explanation:

Given that:

The sample of carbon and oxygen = 5.5g

where carbon makes 35% of the mass of the substances.

It implies that oxygen will make: (100 - 35)% = 65%

Suppose y be the mass of the oxygen;

Then:

[tex]y = \dfrac{(100-35)}{100} \times 5.5 \ g[/tex]

[tex]y = \dfrac{(65)} {100} \times 5.5 \ g[/tex]

[tex]y = 3.575 \ g[/tex]

The mass of carbon [tex]= \dfrac{35}{100} \times 5.5 \ g[/tex]

= 1.925 g

Joseph Priestly is frequently credited with the discovery of oxygen, and was reported to have produced molecular oxygen from the decomposition reaction of mercury(II) oxide, which is the reverse of the synthesis of HgO depicted in the following equation. [tex]4Hg(l)+2O_2(g)\rightarrow 4 HgO(s) [/tex]Determine the value of [tex]\Delta ΔH°rxn[/tex] for the synthesis, given that [tex]\Delta H_f^0[/tex] for HgO is -90.7 kJ/mol.

Answer: The enthalpy change for this reaction is, -362.8 kJ

Explanation:

The balanced chemical reaction is,

[tex]4Hg(l)+2O_2(g)\rightarrow 4HgO(s)[/tex]

The expression for enthalpy change is,

[tex]\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)][/tex]

[tex]\Delta H=[(n_{HgO}\times \Delta H_{HgO})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{Hg}\times \Delta H_{Hg})][/tex]

where,

n = number of moles

[tex]\Delta H_{O_2}=0[/tex] (as heat of formation of substances in their standard state is zero

[tex]\Delta H_{Hg}=0[/tex] (as heat of formation of substances in their standard state is zero

Now put all the given values in this expression, we get

[tex]\Delta H=[(4\times -90.7)]-[(2\times 0)+(4\times 0)][/tex]

[tex]\Delta H=-362.8kJ[/tex]

Therefore, the enthalpy change for this reaction is, -362.8 kJ

Answer:

Ideal Gas

The ideal gas is extremely small and the mass is almost zero and no volume Ideal gas is also considered as a point mass.

Real Gas

The molecules of real gas occupy space though they are small particles and also have volume.

anation:

The differences between an ideal gas and a real gas are that the ideal gas follows the gas laws perfectly under all conditions. Whereas a real gas deviates from ideal gas behaviors.

The ideal gas law, also known as the general gas equation, is a fundamental principle in thermodynamics and relates the pressure, volume, temperature, and number of moles of an ideal gas.

An ideal gas is a theoretical gas that follows the gas laws perfectly under all conditions of temperature and pressure. It is assumed to have no volume, no intermolecular forces, and elastic collisions between its particles. An ideal gas also obeys the ideal gas law.

On the other hand, a real gas is a gas that does not follow the gas laws perfectly under all conditions of temperature and pressure. Real gases have volume and intermolecular forces that affect their behavior. These forces cause deviations from ideal gas behavior, especially at high pressures and low temperatures.

In summary, while an ideal gas is a theoretical gas that follows the gas laws perfectly under all conditions, a real gas is a gas that deviates from ideal gas behavior due to its volume, intermolecular forces, and non-elastic collisions between its particles.

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Answer:

Explanation:

Bromine >Tellurium > Phosphorus > Helium > Sodium

Electron affinity of Bromine , Tellurium , Phosphorus are positive , of helium is zero and of sodium is negative .

Answer:

I>Sn>Xe

Explanation:

Electron affinity refers to the ability of an atom to accept electron(s) and form a negative ion.

We know that electron affinity is a periodic trend that increases across the period but decreases down the group.

Hence the, electron affinity of iodine is far higher than that of tin. However, xenon is a noble gas and does not accept electrons. Hence, it has an electron affinity of 0 KJ/mol.

Answer:

all of the above

Explanation:

now I will bless you with this-

The molecular formula of hydrate : CaCl₂.6 H₂O

So there are 6 molecules of H₂O

Given

54.7g CaCl₂ and 53.64 g H₂O

Required

The number of molecules H₂O

Solution

mol CaCl₂ :

= mass : MW

= 54.7 : 111 g/mol

= 0.493

mol H₂O :

= 53.64 : 18 g/mol

= 2.98

mol ratio H₂O : CaCl₂ :

= 2.98/0.493 : 0.493/0.493

= 6 : 1

Answer:

0 for the elemental form, +2 in its compounds.

Answer:

The mass in grams of N₂O gas that can be dissolved is 0.18 g

Explanation:

The solubility of a gas is proportional to the partial pressure of that gas, over a determined solvent. That's what Henry's law states. We see the formula:

S = K . Pp

Where S is solubility and K is Henry's constant. This specific for each gas and each temperature, while Pp means partial pressure.

We replace data:

S = 0.025 M/atm .  0.69atm

S = 0.01725 M

This is the solubility of the gas, so now, we need to know what mass of gas is solubilized. We convert the moles, with the volume of water.

0.01725 mol/L . 0.235 L = 4.05×10⁻³ moles

Now, we determine the mass in grams:  4.05×10⁻³ mol . 28 g / 1mol =

0.1782 g

Answer:  On Earth, liquid water exists on the surface in the form of oceans, lakes and rivers. It also exists below ground as groundwater, in wells and aquifers. Water vapor is most visible as clouds and fog. The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and icebergs.