Which of the following is a physical change? (1 point)
A) Turning a solid sodium and chlorine gas into salt
B) burning a piece of wood
C) Forming a mixture
D) Food turning into waste in the intestines

Answer:

0.4816 mol S

Explanation:

I'm going to answer this question under the assumption that the question is how many moles of sulfur are present in 34.68 grams of disulfur pentoxide.

The molecular formula of disulfur pentoxide is S₂O₅ (di means two and penta means five).

Now we convert 34.68 g of S₂O₅ into moles, using its molar mass:

Then we convert moles of S₂O₅ into moles of S, given that there are two moles of S per S₂O₅ mol:

Answer:

A

Explanation:

195.49 g K x 1 mole / 39.01 g x 6.022 x 10^23 atoms/mole = 30.11 x 10^23 = 3.011 x 10^24

The number of K atoms present in 195.49 grams of K is 3.0110 × 10²⁴ atoms. The correct option is a 3.0110 x 10²⁴.

From the question,

We are to determine the number of K atoms present in 195.49 grams of K.

First, we will determine the number of moles K present

Using the formula,

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

Atomic mass of K = 39.0983 g/mol

Number of moles of K present = [tex]\frac{195.49}{39.0983}[/tex]

Number of moles of K present = 4.99996 moles

Number of moles of K present ≅ 5 moles

Now, for the number of atoms present

From the formula

Number of atoms = Number of atoms × Avogadro's constant

Number of K atoms present = 5 × 6.022 × 10²³

Number of K atoms present = 5 × 6.022 × 10²³

Number of K atoms present = 30.11 × 10²³

Number of K atoms present = 3.0110 × 10²⁴ atoms

Hence, the number of K atoms present in 195.49 grams of K is 3.0110 × 10²⁴ atoms. The correct option is a 3.0110 x 10²⁴.

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Answer:

[tex]t_{1/2}=375.5min[/tex]

Explanation:

Hello!

In this case, since this problem refers to two different temperatures, it is possible to compute the rate constant at 652 K given the half-life at such temperature:

[tex]k=\frac{ln(2)}{58.0 min}=0.0120min^{-1}[/tex]

Next, by using the T-variable version of the Arrhenius equation, we can compute the rate constant at 623 K:

[tex]ln(\frac{k_2}{k_1} )=-\frac{Ea}{R}(\frac{1}{T_2}-\frac{1}{T_1} ) \\\\ln(\frac{k_2}{k_1} )=-\frac{218000J/mol}{8.3145\frac{J}{mol*K}}(\frac{1}{623K}-\frac{1}{652K})\\\\ln(\frac{k_2}{k_1} )=-1.872\\\\k_2=0.0120min^{-1}exp(-1.872)\\\\k_2=0.00185min^{-1}[/tex]

Finally, the half-life at 623 K turns out to be:

[tex]t_{1/2}=\frac{ln(2)}{0.00185min^{-1}} \\\\t_{1/2}=375.5min[/tex]

Best regards!

answer: white fur works as a camouflage against the white snow, allowing polar bears an advantage when hunting for food and hiding from predators

Answer:

[tex]H^+(aq)+(ClO)^-(aq)\rightarrow HClO{(aq)}[/tex]

Explanation:

Hello there!

In this case, since perchloric acid is HClO4 and is a strong acid and calcium hypochlorite is Ca(ClO)2, the undergoing molecular chemical reaction turns out:

[tex]2HClO_4{(aq)}+Ca(ClO)_2{(aq)}\rightarrow 2HClO{(aq)}+Ca(ClO_4)_2{(aq)}[/tex]

Thus, since the resulting hypochlorous acid is weak, it does not fully ionize, so it remains unionized, however, we can write the ions for the other species:

[tex]2H^++2(ClO_4)^-+Ca^{2+}+2(ClO)^-\rightarrow 2HClO{(aq)}+Ca^{2+}+2(ClO_4)^-[/tex]

Now, we can cancel out the spectator ions, calcium and perchlorate, to obtain:

[tex]2H^+(aq)+2(ClO)^-(aq)\rightarrow 2HClO{(aq)}\\\\H^+(aq)+(ClO)^-(aq)\rightarrow HClO{(aq)}[/tex]

Best regards!

Answer:

B) Hope this helps! :)

Explanation:

More water is better but not always because access to water or sunlight is harmful to plants.

Water is an important part not only for plants to run the ecosystem it is always important but in a fixed amount not in a large quantity as access to anything is harmful t the environment as access to water can also damage the ecosystem.

Water is said to be life for plants but more water leads them not to grow in a manageable way like access to water in the soil will not allow the soil to hold the plant for growing plants will float on sol and the root will not be able to grow.

Therefore, water is essential always but in fixed quantity not in the large amount in access.

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Answer:

Build wind-powered pumps to use groundwater

Explanation:

Answer:

Its B!

Explanation:

Did it on the test!

When light travels from less dense air to denser glass or water, it slows down. Slowing down of a ray of light changes the direction of the ray of light.

Light that travels in a straight line in one direction is called a ray of light. When a group of light emanates from a source, it is called a beam of light. A beam of light is defined as the path of a photon or a group of photons traveling through a space appearing as a column of light.

There are three types of light rays. They are

Example of a beam is a beam of light with a pass from a laser or laser pointer. A beam of light is made up of particles called photons that carry specific amounts of energy. We cannot measure the length of a beam.

Thus, when light travels from less dense air to denser glass or water, it slows down. Slowing down of a ray of light changes the direction of the ray of light.

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Answer: B. [tex]\frac{\text {2 mol} H_2O}{\text {2 mol HCl}}[/tex]

Explanation:

The balanced chemical equation is:

[tex]Ca(OH)_2(aq)+2HCl(aq)\rightarrow CaCl_2(aq)+2H_2O(l)[/tex]

is the limiting reagent as it limits the formation of product and is the excess reagent.

According to stoichiometry :

2 moles of produce = 2 moles of

Thus 3.25 moles of [tex]HCl[/tex] will produce=[tex]\frac{2}{2}\times 3.25=3.25moles[/tex]  of [tex]H_2O[/tex]

Thus the tile used is [tex]\frac{\text {2 mol } H_2O}{\text {2 mol HCl}}[/tex]

Answer:Below is the answer to all 5 of stoichiometry question

Explanation:

1. B. The student chose the correct tile, but needs to flip the tile to make the units cancel.

2.C. 2.3 moles of oxygen (O2)

3. B. Tile B

4. A. 2.9 moles of aluminum sulfate

5. B. 42.0 grams

Answer:

Chemical reactions leads to formation of a new chemical subtance.

Answer:

200 meters

Explanation:

Answer:

B. Producers and decomposers

Explanation:

Producers aka plants convert raw energy into chemical energy.

Decomposers are responsible for decomposing dead organisms.

Answer:

the answer is b

Explanation:

Because it provides for the restoration of the life cycle

Answer:

I got you! I think the answer is D. Warmer air can hold more water vapor than colder air.

Explanation:

Although this statement is true, I could be incorrect, but it is unlikely. When warm air recieves more water vapor it expands while cold air becomes packed and unstable.

Hope this helps out, good luck! (¤﹏¤)

~ #LearnWithBrainly ~

Answer:

Explanation:

Answer:

280

Explanation:

total pressure=partial pressure (He)+partial pressure (N2)+partial pressure (H2)

Answer:

389929.827

Explanation:

33806.78° C

Answer:

(a) 3.96 (w/w) %

(b) 0.663M

Explanation:

The acetic acid, CH₃COOH, reacts with NaOH as follows:

CH₃COOH + NaOH → CH₃COONa + H₂O

Where 1 mole of acetic acid reacts with 1 mole of NaOH

In the equivalence point of the titration, the moles of acetic acid are equal to moles of NaOH added. To solve this question we need to find the moles of NaOH and thus, the mass of acetic acid

Moles NaOH = Moles acetic acid:

33.0cm³ = 0.033L * (0.100moles / L) = 0.0033 moles

Mass acetic acid -Molar mass: 60g/mol-:

0.0033 moles * (60g / mol) = 0.198g

a) Weight percent is 100 times the ratio of the mass of acetic acid (0.198g) in the mass of vinegar (5.00g):

0.198g / 5.00g * 100 = 3.96 (w/w) %

(b) The volume of the vinegar in the 5.00g is:

5.00g * (1mL / 1.005g) * (1L / 1000mL) = 0.00498L

And the molarity is:

0.0033moles / 0.00498L = 0.663M

Answer:

a) 0.099 L

b) 9.9

Explanation:

Now, given the equation for the decomposition of H2O2;

2H2O2(l) ------> 2H2O(l) + O2(g)

Mass of H2O2;

percent w/v concentration = mass/volume * 100

volume = 10.0-mL

percent w/v concentration = 3.0 percent

mass of  H2O2 = x

3 = x/ 10 * 100

30 = 100x

x = 30/100

x = 0.3 g of H2O2

Number of moles in  0.3 g of H2O2 = mass/ molar mass

Molar mass of H2O2 = 34.0147 g/mol

Number of moles in  0.3 g of H2O2 = 0.3g/34.0147 g/mol

= 0.0088 moles

From the reaction equation;

2 moles of H2O2 yields 1 mole of oxygen

0.0088 moles of H2O2 = 0.0088 * 1/2  = 0.0044 moles of oxygen

If 1 mole of oxygen occupies 22.4 L

0.0044 moles of oxygen occupies 0.0044 *  22.4/1

= 0.099 L

b) initial volume of the H2O2 solution = 10 * 10-3 L

Hence, ratio of the volume of O2 collected to the initial volume of the H2O2 solution = 0.099 L/10 * 10-3 L = 9.9

Answer:

its exothermic oooooooooooooooooooooo

Answer:

0.1332 L

Explanation:

The balanced chemical equation is the following:

2 Na(s) + 2 H₂O(l) → 2 NaOH(aq) + H₂(g)

According to the equation, 2 moles of water (H₂O) produce 1 mol of hydrogen (H₂). So, the stoichiometric ratio is 1 mol H₂/2 mol H₂O. To calculate how many moles of H₂O we need to produce 3.7 moles of H₂, we multiply the moles by the stoichiometric ratio:

3.7 moles H₂ x 2 mol H₂O/1 mol H₂ = 7.4 moles H₂O

Now, we have to convert the moles of water to liters. For this, we have to consider the molecular weight (MW) of water and its density (let's consider 1.0 g/mL).

MW(H₂O) = (2 x 1 g/mol H) + 16 g/mol = 18 g/mol

7.4 moles H₂O x 18 g/mol = 133.2 g

133.2 g/(1.0 g/ml) = 133.2 mL

133.2 ml x 1 L/1000 ml = 0.1332 L

Therefore, approximately 0.13 liters of water are needed.

Answer:

1461.7 g of AgI

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

CaI₂ + 2AgNO₃ —> 2AgI + Ca(NO₃)₂

From the balanced equation above,

1 mole of CaI₂ reacted to produce 2 moles of AgI.

Next, we shall determine the number of mole AgI produced by the reaction of 3.11 moles of CaI₂. This can be obtained as follow:

From the balanced equation above,

1 mole of CaI₂ reacted to produce 2 moles of AgI.

Therefore, 3.11 moles of CaI₂ will react to produce = 3.11 × 2 = 6.22 moles of AgI

Finally, we shall determine the mass of 6.22 moles of AgI. This can be obtained as follow:

Mole of AgI = 6.22 moles

Molar mass of AgI = 108 + 127

= 235 g/mol

Mass of AgI =?

Mass = mole × molar mass

Mass of AgI = 6.22 × 235

Mass of AgI = 1461.7 g

Therefore, 1461.7 g of AgI were obtained from the reaction.

Explanation:

          Whenever an ion in a solution is common for any two different salts, a common ion effect is formed that serves as the sources. Further addition of the common ion that is the product of a dissolution of the first. Adding the product ion decreases the solubility for the 1st salt.

           Equilibrium made between the reactants as well as the products are described by the equilibrium constant. This expression for the insoluble salt is written using the rules that were used for other equilibriums. Equilibrium constant is known as the solubility product, Ksp.

           The interactions between the ions are the results of the activity effects. The ion's activity is influenced by the surrounding. In case of water molecule, the activity of the ion has different values from the one in the middle of the counterion cloud. The Ksp values are used to decide for the order of the precipitation of any two or more of insoluble salts.

Answer:

i don't know what happened but r.i.p account

Answer:

Rest in peace.

Explanation: I need these 50 points tho.

Answer:

Which answer would represent 0.001 moles?

Answer:

0.5 mole of CO₂.

Explanation:

We'll begin by calculating the number of mole in 42 g of baking soda (NaHCO₃). This can be obtained as follow:

Mass of NaHCO₃ = 42 g

Molar mass of NaHCO₃ = 23 + 1 + 12 + (16×3)

= 23 + 1 + 12 + 48

= 84 g/mol

Mole of NaHCO₃ =?

Mole = mass / molar mass

Mole of NaHCO₃ = 42/84

Mole of NaHCO₃ = 0.5 mole

Next, balanced equation for the reaction. This is given below:

NaHCO₃ + HC₂H₃O₂ → NaC₂H₃O₂ + H₂O + CO₂

From the balanced equation above,

1 mole of NaHCO₃ reacted to produce 1 mole of CO₂

Finally, we shall determine the number of mole of CO₂ produced by the reaction of 42 g (i.e 0.5 mole) of NaHCO₃. This can be obtained as follow:

From the balanced equation above,

1 mole of NaHCO₃ reacted to produce 1 mole of CO₂.

Therefore, 0.5 mole of NaHCO₃ will also react to produce 0.5 mole of CO₂.

Thus, 0.5 mole of CO₂ was obtained from the reaction.

Answer:

Option D. 3 ppm isopropanol.

Explanation:

From the question given above, the following data were obtained:

Mass of isopropanol = 6 mg

Mass of water = 2 Kg

Isopropanol concentration =?

Concentration = mass isopropanol / mass of water

Isopropanol concentration = 6 mg / 2 kg

Isopropanol concentration = 3 mg/Kg

Next, we shall convert 3 mg/Kg to ppm. This can be obtained as follow:

Recall:

1 mg/Kg = 1 ppm

Therefore,

3 mg/Kg = 3 ppm

Thus, the isopropanol concentration is 3 ppm.

Answer:

Explanation:

We know that momentum is the product of mass and velocity so here

mass (m) = 1700 kg

velocity (v) = 13 m/s

So now

momentum = m * v

                   = 1700 * 13

                   = 22100 kg m/s

hope it helps :)