where are the first repost of new scientific discoveries published A.) Internet Sites B.) Magazines C.) encyclopedias D.) Scientific journals

Answer:

n = 9

Explanation:

Given parameters:

Molar mass of Na₂SO₄.nH₂O = 304.04gmol⁻¹

Solution

To find the hydration number n, we simply express atomic masses of the atoms in the compound as equal to the given molar mass.

Atomic mass of Na = 23g

                           S = 32g

                           O = 16g

                            H = 1g

       Molar mass of the compound is evaluated as:

       2(23) + 32 + 4(16) + n[2(1) + 16] = 304.04

       46 + 32 + 64 + 18n = 304.04

          142 + 18n = 304.04

              18n = 304.04 - 142

              18n = 162.04

                n = 9

Answer:

Its not bar graph

Explanation:

Answer:

C- Line Graph

Explanation:

Answer:

0.22 atm

Explanation:

The total pressure is the sum of the partial pressures.

P = P₁ + P₂ + P₃

1.25 atm = 0.68 atm + 0.35 atm + P

P = 0.22 atm

Answer:

0.22 atm

Explanation:

First, you need to add up each of the values of the known gases

0.68+0.35

Then you need to subtract that value from the total pressure to find the partial pressure of the third value

1.25-(0.68+0.35)

By doing that you get the answer of 0.22 atm

Answer:

1-3 2-2 3-1

Explanation:

Answer:

236588 cm3

Explanation:

If a large recipe calls for 250 quarts of milk, there are 236588 cm3.

Multiply the volume value by 946.353

Answer:

Dr. Patel, a cardiologist, presents her findings on heart disease

Explanation:

Answer: C. The number of protons

Explanation: because when you take or add protons to an element it becomes another element.

The answer is in the photo

Answer : The moles of [tex]CO_2[/tex] produced are, 3.462 moles.

Explanation : given,

Mass of [tex]C_6H_6[/tex] = 45.0 g

Molar mass of [tex]C_6H_6[/tex] = 78 g/mole

First we have to calculate the moles of [tex]C_6H_6[/tex].

[tex]\text{Moles of }C_6H_6=\frac{\text{Mass of }C_6H_6}{\text{Molar mass of }C_6H_6}=\frac{45.0g}{78g/mole}=0.577moles[/tex]

Now we have to calculate the moles of [tex]CO_2[/tex]

The given balanced chemical reaction is,

[tex]2C_6_H6+15O_2\rightarrow 12CO_2+6H_2O[/tex]

From the balanced chemical reaction, we conclude that

As, 2 moles of [tex]C_6H_6[/tex] react to give 12 moles of [tex]CO_2[/tex].

So, 0.577 moles of [tex]C_6H_6[/tex] react to give [tex]\frac{12}{2}\times 0.577=3.462[/tex] moles of [tex]CO_2[/tex].

Therefore, the moles of [tex]CO_2[/tex] produced are, 3.462 moles.

Answer:

Gamma Radiation maybe

Explanation:

The atomic particles given off as a result of nuclear fission are Beta and Alpha particles, so the only thing left is gamma radiation.

I hope this helps, and as always, I am joyous to assist anyone at any time.

Answer:

cation

Explanation:

Answer:

Cation

Explanation:

Cation is the name of an ion with a positive charge.

Cation is made electron loss.

Also, it means atoms forced into position or gained.

Answer:

Approximately 3318 disintegrations per minute.

Explanation:

The activity [tex]A[/tex] of a radioactive decay at time [tex]t[/tex] can be found with the following equation:

[tex]\displaystyle A(t) = A_0 \cdot \mathrm{e}^{-\lambda\cdot t}[/tex].

In this equation,

The decay constant here can be found using the activity after 10 days. As long as both times are in the same unit (days in this case,) conversion will not be necessary.

[tex]A(10) = A_0\cdot \mathrm{e}^{\rm -\lambda \times 10\;day}= (\mathrm{8540\; min^{-1}})\cdot \mathrm{e}^{\rm -\lambda \times 10\;day}[/tex].

[tex]A(10) = \rm 6690\; min^{-1}[/tex].

[tex]\displaystyle \frac{\rm 6690\; min^{-1}}{\mathrm{8540\; min^{-1}}} = \mathrm{e}^{\rm -\lambda \times 10\;day}[/tex]

Apply the natural logarithm to both sides of this equation.

[tex]\displaystyle \ln{\left(\frac{\rm 6690\; min^{-1}}{\mathrm{8540\; min^{-1}}}\right)} = \ln{\left(\mathrm{e}^{\rm -\lambda \times 10\;day}\right)}[/tex].

[tex]\displaystyle \rm -\lambda \cdot (10\;day) = \ln{\left(\frac{\rm 6690\; min^{-1}}{\mathrm{8540\; min^{-1}}}\right)}[/tex].

[tex]\displaystyle \rm \lambda= \rm \frac{\displaystyle \ln{\left(\frac{\rm 6690\; min^{-1}}{\mathrm{8540\; min^{-1}}}\right)}}{-10 \; day} \approx 0.0200280\; day^{-1}[/tex].

Note that the unit of the decay constant [tex]\lambda[/tex] is [tex]\rm day^{-1}[/tex] (the reciprocal of days.) The exponent [tex]-\lambda \cdot t[/tex] should be dimensionless. In other words, the unit of [tex]t[/tex] should also be days. This observation confirms that there's no need for unit conversion as long as the two times are in the same unit.

Apply the equation for decay activity at time [tex]t[/tex] to find the decay activity after 47.2 days.

[tex]\displaystyle \begin{aligned}A(t)& = A_0 \cdot \mathrm{e}^{-\lambda\cdot t}\\&\approx \rm \left(8540\; min^{-1}\right)\cdot \mathrm{e}^{-0.0200280\; day^{-1}\times 47.2\;day}\\&\approx \rm 3318\; min^{-1}\end{aligned}[/tex].

By dimensional analysis, the unit of activity here should also be disintegrations per minute. The activity after 47.2 days will be approximately 3318 disintegrations per minute.

Answer:

14.3 g SO₃

Explanation:

2S + 3O₂ → 2SO₃

First, find the limiting reactant.  To do that, calculate the mass of oxygen needed to react with all the sulfur.

5.71 g S × (1 mol S / 32 g S) = 0.178 mol S

0.178 mol S × (3 mol O₂ / 2 mol S) = 0.268 mol O₂

0.268 mol O₂ × (32 g O₂ / mol O₂) = 8.57 g O₂

There are 10.0 g of O₂, so there's enough oxygen.  The limiting reactant is therefore sulfur.

Use the mass of sulfur to calculate the mass of sulfur trioxide.

5.71 g S × (1 mol S / 32 g S) = 0.178 mol S

0.178 mol S × (2 mol SO₃ / 2 mol S) = 0.178 mol SO₃

0.178 mol SO₃ × (80 g SO₃ / mol SO₃) = 14.3 g SO₃

The answer is:

[tex]MolarConcentration=\frac{3.5moles}{volume(1.5L)}=2.33molar[/tex]

Since there is not information about the solute but only its mass, we need to assume that we are calculating the molar concentration of a solution or molarity. So, need to use the following formula:

[tex]MolarConcentration=\frac{mass(solute)}{volume(solution)}[/tex]

Now, we know that the mass of the solute is equal  3.5 moles and the volume is equal to 1500 mL or 1.5L

Then, substituting into the equation, we have:

[tex]MolarConcentration=\frac{3.5moles}{1.5L}=2.33molar[/tex]

Have a nice day!

Hey there!:

Molarity, molar concentration, concentration in mol/L or concentration in quantity of matter is the ratio of the amount of matter of the solute (mol) by the solution volume (in liters), expressed in the Unit mol/L (molar).

Number of moles  = 3.5 moles

1 L = 1000 mL

Volume in liters  = 1500 mL / 1000 =>  1.5 L

Therefore:

Molarity = number of moles / Volume in liters:

Molarity = 3.5 / 1.5

Molarity =  2.333 M

Hope this helps!

Answer:

(C) 503 g

Explanation:

Balanced reaction:

2NH₃ + 2O₂ → N₂O + 3H₂O

Stoichiometry:

317 g NH₃ × (1 mol NH₃ / 17.03 g NH₃) = 18.61 mol NH₃

18.61 mol NH₃ × (3 mol H₂O / 2 mol NH₃) = 27.92 mol H₂O

27.92 mol H₂O × (18.02 g H₂O / mol H₂O) = 503 g H₂O

Answer:

(C) 503 g of water, H2O, are produced from 317 grams of ammonia and excess oxygen

Explanation:

[tex]2 NH_3+2 O_2>N_2 O+3 H_2 O[/tex]

Molar mass of

[tex]H_2 O=(2\times1.008)+15.999=18.02 g/mol[/tex]

Molar mass of

[tex]NH_3=14.01+(3\times1.008)=17.03 g/mol[/tex]

The conversions are

Step 1:

Mass [tex]NH_3[/tex] to moles [tex]NH_3[/tex] by dividing with molar mass [tex]NH_3[/tex]

Step 2:

Moles [tex]NH_3[/tex] to moles [tex]H_2 O[/tex] by using mole ratio of [tex]NH_3:H_2 O[/tex] i.e., 2 : 3

Step 3:

Moles [tex]H_2 O[/tex] to mass [tex]H_2 O[/tex] by multiplying with molar mass [tex]H_2 O[/tex]

[tex]317gNH_3  \times \frac {(1mol NH_3)}{(17.03gNH_3 )} \times \frac {(3mol H_2 O)}{(2mol NH_3 )} \times \frac {(18.02g H_2 O)}{(1mol H_2 O)}[/tex]

[tex]= 503g H_2 O[/tex] is formed.

(Answer)

Please note :

To convert moles to mass, we multiply by molar mass  

To convert mass to moles, we divide by molar mass

Molar mass is the mass of 1 mole of the substance

For example molar mass of [tex]CO_2[/tex] is

[tex](12.0+2\times16)=44 g/mol[/tex]

(we just add the atomic mass of the atoms to get the molar mass of the substance).

Explanation:

First conversion factor: moles of SO₄ per mole of Al₂(SO₄)₃.

3 mol SO₄ / mol Al₂(SO₄)₃

Second conversion factor: moles of S per mole of SO₄.

1 mol S / mol SO₄

Altogether:

(3 mol SO₄ / mol Al₂(SO₄)₃) × (1 mol S / mol SO₄) = 3 mol S / mol Al₂(SO₄)₃

To relate moles of S to moles of Al2(SO4)3, we use the compound's 2:3 ratio to establish that 1 mole of Al2(SO4)3 has 3 moles of S. Conversion factors are 1 mole Al2(SO4)3/3 moles S and 3 moles S/1 mole Al2(SO4)3. These allow for conversions between the moles of the two substances.

To construct a pair of conversion factors that relate moles of S to moles of Al2(SO4)3, we need to look at the chemical compound's formula. The compound aluminum sulfate, Al2(SO4)3, shows there are three sulfate (SO42-) ions for every two aluminum (Al3+) ions.

This indicates a 2:3 ratio between Al and SO4 in the compound. Each sulfate ion contains one atom of sulfur (S), so for every mole of Al2(SO4)3, there are three moles of sulfur atoms (S). Thereby, the conversion factors are:

These factors can be used to convert moles of sulfur to moles of aluminum sulfate and vice versa.

Answer:

6.022 x 10^23

Explanation:

There are 6.022 x 10^23 electrons that may bank in 1.6 g of methane.

10×6.023×10²²

6.023 ×10²³

Answer:

6.02 × 10^23

Explanation:

Number of moles of methane = 1.6/16 = 0.1

In one mole there are 6.02 × 10^23 atoms

Thus, in 0.1 mole there are 0.1 ×6.02 × 10^23 atoms =6.02 × 10^22 atoms

Hence total number of electrons = number of electrons present in CH4 × atoms present in 0.1 mole.

=10×6.02 × 10^22 =6.02 × 10^23

Answer:

[Ar] 4s2 3d10 4p3

Explanation:

Arsenic is Element 33. It is the 15th element in the Fourth Row, following the noble gas Ar at the end of the Third Row.

Thus, its noble gas electron configuration is

[Ar] 4s2 3d10 4p3

Answer:

[H⁺] = 3.02 x 10⁻¹⁰M

Explanation:

Given parameters:

pH of the solution = 9.52

Unknown:

Concentration of the solution

Solution

There is a relationship between the pH and concentration of a solution.

                     pH = -log₁₀[H⁺]

The unknown here is [H⁺],

Now making it the subject of the formula

           [H⁺] = Inverse log₁₀(-pH)

           [H⁺] = Inverse log₁₀(-9.52)

              [H⁺] = 3.02 x 10⁻¹⁰M

Answer:

Explanation:a cells state potential of the cell is the standard state conditions 1 mole per liter (1 m) and pressure of atmospheric 25oC

Answer:

Total of all numbers added with the correct rounding and number of significant figures

Explanation:

1. Add up all the numbers

8.32+8.00+8.30+8.3

2. Determine how many significant figures should be in your final answer. When it comes to addition, it will be the fewest number of decimal places. since 8.3 has one decimal place, your final answer should only have one decimal place.

3. Round your final answer to the nearest tenths

Give the numbers that we have to add up.

Answer: D

Explanation:

Just took the test

Final answer:

Niels Bohr's contribution to atomic theory was his proposal of the Bohr's Model, which introduced the concept of electron orbits and explained the atomic spectrum of hydrogen.

Explanation:

Niels Bohr made significant contributions to atomic theory by proposing a model of the atom in 1913 called the Bohr's Model. This model incorporated Rutherford's planetary model and explained the atomic spectrum of hydrogen. Bohr's model was based on the concept that electrons move around the nucleus in circular orbits at certain allowed radii, and it introduced quantum mechanics principles. However, it is important to note that Bohr's model has been superseded by more accurate and complex models in modern atomic theory.

Answer: B. Detecting the presence of humans trapped under collapsed buildings.

Explanation: Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion. Infrared technology is found not just in industry, but also in every-day life. Televisions, for example, use an infrared detector to interpret the signals sent from a remote control.

Answer:

D) constructive

Explanation:

Deposition is a constructive force since it involves dumping sediment in a particular location.

Constructive is the correct answer. A deposition is a constructive force when it involves dumping into sediment a particular location. I hope this will help you. Have a wonderful day!

Answer:

D) forms hydronium ions in water

Explanation:

Texture and conductivity are physical properties which makes answer A and B wrong. Answer C does not refer to a chemical reaction.

Answer:

Explanation:

Oxidation state of Cr in CrPO₄

As a general rule, the algebraic sum of all the oxidation numbers of all atoms in a neutral compound is zero.

The compound above is in its neutral state and we sum all the oxidation numbers and equate to zero:

The oxidation number of P is -2

                                           O is -2

Let the oxidation number of Cr be x:

                              x + (-2) + 4(-2) = 0

                              x -2-8 = 0

                               x -10 = 0

                                x = +10

For Cr in Cr₃(PO₄)₂

         Using the same rule:

        2(x) + 2[-2 + 4(-2)] = 0

           2x + 2(-2-8) = 0

            2x -20 = 0

                x = +10

Answer:

[tex]CrPO_4: Cr +3\\Cr_3(PO_4)_2: Cr+2[/tex]

Explanation:

[tex]CrPO_4[/tex] and [tex]Cr_3(PO_4)_2[/tex] are compounds known as ternary salts

This means that they are formed by a metal or a non-metal and an anion

 Its formula is [tex]M_x(X_yO_z)_w[/tex], that is, the cation is written first and then the anion and the simplified charges are exchanged if possible.

The anion [tex]PO_4[/tex] has a load of -3: [tex]PO_{4}^{-3}[/tex]

Let's look at the first compound [tex]CrPO_4[/tex] we observe that when exchanging the charges 3 of the[tex]PO_4[/tex] does not appear therefore the charges are simplified as the charges are completely simplified, it means that the chromium has the same valence (numerically but with opposite sign) that the anion

Therefore the oxidation state of Cr in [tex]CrPO_4[/tex] is +3

Let's look at the second compound [tex]Cr_3(PO_4)_2[/tex], it is observed that when exchanging the valences, the 3 of the [tex]PO_4[/tex] is with the chromium, and with the anion is  2

As valencia are not multiples, they cannot be simplified.

When exchanging the valences, the[tex]PO_4[/tex] has the valence corresponding to the chromium which in this case is + 2

Iron is unsuitable for fuel cell electrodes due to its reactivity and corrosion, whereas platinum is favored for being inert and stable in electrochemical reactions.

Iron is not a suitable metal for the electrodes of a fuel cell because it is reactive and can undergo corrosion, especially when in contact with water, leading to the degradation of the cell's performance. Instead, platinum is often used for electrodes because it is an inert metal that does not react during redox processes. This ensures that the platinum electrodes do not appear in the overall electrochemical reaction of the cell, thus maintaining their integrity and the efficiency of the fuel cell.

Answer:

B. Chemicals can keep bread fresher longer.

Explanation:

I checked the label of my bread  :)) and I found one ingredient which keep the freshness:  

ascorbic acoid (vitamin C) - it has antioxidant properties

Answer:

Chemicals can keep bread fresher longer.

Answer:

A double bond between carbon atoms

Explanation:

The suffix -ene is used for alkenes, which tells you that the molecule has a carbon-carbon double bond.

These are 6 questions and 6 answers, each with its explanation.

Answer:

Explanation:

a. 0.7540

When there are not digits (non-zero digits) before the decimal point, the significant digits are all the decimal digits from the first non-zero decimal. So, in this case, they are all the shown digits: 7, 5, 4, and 0, i.e. 4 significant figures.

b) 12500

When there is not decimal point, the significant digits include all the digits before only zeros appear. So, they are 1, 2, and 5, i.e. 3 significant figures.

When it is meant that all the digits are significan, a perod must be added, in this way: 12500. The last point is part of the number, it does not add value, but indicates that all the digits are significant.

c) 10000.01

This is the only number from the list with both decimal and non-decimal digits.

When there are digits before and after the decimal point, the significant digits include all the digits before the decimal point and all the decimal digits. So they are 1, 0, 0, 0, 0, 0, and 1, i.e. 7 significant digits.

d) 1200

Again, when there is not decimal point, the significant digits include all the digits before only zeros appear. So, they are 1 and 2, i.e. 2 significant figures.

The two last zeros do not count as significant digits. If the number were written 1200., i.e. showing a decimal point but without digits after the decimal point, then all the four digits were singnificant.

e) 1.04 × 10⁴

This number is written in scientific notation.

The numbers before the power of 10 are called mantissa.

For a number written in scientific notation, the significant digits are the digits in the mantissa, i.e. 1.04. So, the number of significant digits is 3 (1, 0, and 4).

f) 0.0080050

For a number with only decimal digits (there are not digits with value before the decimal point), the zeros after the decimal point and before the first non-zero digit do not count as significant figures. So, the significant figures are: 8, 0, 0, 5, and 0, i.e. 5 significant figures.