Cars are the leading cause of____

1. carbon dioxide
2. nitrogen oxide
3.carbon monoxide

pollution

Answer:

yee I'm excellent in maths and science

Answer:

I believe the answer is "b". "During the experiment, the scientist has only one element, or variable, that is changed to test the hypothesis."

Explanation:

I remember from last year but I'm not totally sure. Good luck!

The experimental setup has been the design that includes the experimental and the control group. during the experiment, only one variable is changed to test the hypothesis. Thus, option b is correct.

The experiment design includes the testing of the hypothesis to solve the problem and reach the solution through the analysis of the observations. It has been the setup that includes the test and the control group that involves the dependent, independent, and controlled variables.

Testing one variable in the experimental designs means changing one of the elements of the experience to prove the reliability of the hypothesis. This variable is the factor that alters and affects the other factors of the experiment and leads to a cause and effect.

The result of the effect of the hypothesis proves the testability of the experiment and provides solutions to the research question. This further leads to the formulation of the law and theory.

Therefore, option A. testing one variable involves proving the hypothesis.

Learn more about experimental design, here:

https://brainly.com/question/17280313

#SPJ6

Answer:

ΔHreaction (KJ) =  - 78 KJ

The value may vary in relation to the source of the bond enthalpy data.

 Bond enthalpies used  (From a table of bond enthalpies )

Bond           KJ/ mol

C≡O           1080

C-Cl            330

C=O           741

Cl-Cl           243

Explanation:

                         CO(g) + Cl2(g)  →    COCl2(g)

1) Lewis structures

Valence electrons

C     4

O     6

Cl     7

Reactants

CO(g)

In the case of CO, carbon has a negative charge and oxygen a positive charge.

Cl2(g)

Products

COCl2(g)

_______________________

ΔHreaction (KJ) = ∑ n* ΔH ( reactants) - ∑ n* ΔH (product)

ΔHreaction (KJ) =   (ΔHC≡O +   ΔHCl-Cl)  - ( ΔHC=O  + 2* ΔHC-Cl)

Replacing the values

ΔHreaction (KJ) =   (1080 +  243)  - ( 741 + 2* 330)

ΔHreaction (KJ) = 1323 -  1401

                          =  - 78 KJ

Answer: 25

Explanation:

The new volume will be 18 L

The volume of a dry gas of a given mass was inversely proportional to its pressure at constant temperature, according to Boyle's law. At moderate pressures and temperatures, most gases behave like ideal gases.

Calculation of new volume is shown as below:

The new volume of can be calculated by using Boyle's law.

[tex]P_{1} V_{1} = P_{2} V_{2}[/tex]

It is given that, [tex]P_{1}[/tex] = 0.9 atm. [tex]V_{1}[/tex] = 4 L, [tex]P_{2}[/tex] = 0.20 atm

Now, put the values of given data in above equation.

[tex]V_{2}[/tex] = [tex]P_{1}V_{1}[/tex] / [tex]P_{2}[/tex].

[tex]V_{2}[/tex] = (0.9) ×4 / 0.20

= 3.6 / 0.20

= 18 L

therefore, the new volume will be 18 L.

To know more about volume.

https://brainly.com/question/2098026.

#SPJ2

Answer: Psychotherapy

Explanation:

Edge

Answer:

D. Psychotherapy

Explanation:

Did the test

Answer:

[tex]B_3H_6N_3[/tex]

Explanation:

Hello there!

In this case, since the mass percentages in a compound which is wanted to know the molecular formula, can be assumed to be the masses, we first need to compute the moles they have in the formula unit:

[tex]n_B=40.29gB*\frac{1molB}{10.811gB} =3.73molB\\\\n_H=7.51gH*\frac{1molH}{1.01gH} =7.44molH\\\\n_N=52.20gN*\frac{1molN}{14.01gN} =3.73molN[/tex]

Next, we divide each moles by the fewest ones (3.73 mol) in order to find the subscript in the empirical formula first:

[tex]B:\frac{3.73}{3.73}=1 \\\\H:\frac{7.44}{3.73}=2\\\\N:\frac{3.73}{3.73}=1[/tex]

Then, the empirical formula is BH2N whose molar mass is 26.83 g/mol, so the ratio of molecular to empirical is 80.50/26.83=3; therefore, the molecular formula is three times the empirical one:

[tex]B_3H_6N_3[/tex]

Best regards!

Answer:

1.A

Explanation:

please click the heart and rate excellent and brainleist to

Answer:

Explanation:

Answer: The volume of diluted solution is 4 L

Explanation:

According to the dilution law,

[tex]M_1V_1=M_2V_2[/tex]

where,  

[tex]M_1[/tex] = molarity of stock [tex]HCl[/tex] solution = 8 M

[tex]V_1[/tex] = volume of stock [tex]HCl[/tex] solution = 1 L  

[tex]M_1[/tex] = molarity of diluted [tex]HCl[/tex] solution = 2 M

[tex]V_1[/tex] = volume of diluted [tex]HCl[/tex] solution = ?

Putting in the values we get:

[tex]8M\times 1L=2M\times V_2[/tex]

[tex]V_2=4L[/tex]

Therefore, volume of diluted solution is 4 L

I haven't done these in some time, so I'm not sure if they are 100% right.

1) 6.3 moles of H2( 2 mol of NH3 / 3  mol of H2)= 4.2 mol of NH3

6.3 moles of H2( 2 mol of NH3/ 3 mol of H2)(17.04 g of NH3/1 mol NH3)= 71.57 g of NH3

2) 2.5 moles of N2(2 mol of NH3/1 mol of N2)= 5 moles of NH3

2.25 moles of N2(2 mol of NH3/ 1 mol of N2)(6.02x10^23 particles/ 1 mol of NH3)= 3.01x10^24 particles of NH3

3) 425 g of NH3(1 mol of NH3/17.04 g NH3)= 24.9 moles of NH3

425 g of NH3(1 mol of NH3/17.04 g of NH3)(1 mol of N2/2 mol of NH3)(28.02 g of N2/1 mol N2)= 349 g of N2

425 g of NH3(1 mol of NH3/17.04 g of NH3)(1 mol of N2/2 mol of NH3)= 12.5 mol of N2

4) 10 moles NH3(3 moles of H2/2 moles of NH3)= 15 moles H2

10 moles NH3(3 mol of H2/2 mol of NH3)(2.02 g of H2/1 mol of H2)= 30.3 g of H2

30.3 g = .0303 liters of H2

Answer:

n = 0.0102 mol.

Explanation:

Hello there!

In this case, according to the ideal gas law, which allows us to set up a relationship among volume, pressure, temperature and moles, we can define it as:

[tex]PV=nRT[/tex]

Thus, given the volume in liters (0.1000 L), temperature in kelvins (298.15 K) and pressure in atmospheres (2.50 atm), we can solve for moles as shown below:

[tex]n=\frac{PV}{RT}[/tex]

Thereafter, we plug in the aforementioned values to obtain:

[tex]n=\frac{2.50atm*0.1000L}{0.08206\frac{atm*L}{mol*K}*298.15K}\\\\n=0.0102mol[/tex]

Best regards!

Answer:

i think its the gibbous phase

Explanation:

Answer:

b

Explanation:

i know

Answer:

[tex]1s^2\, 2s^2[/tex].

Explanation:

Electron orbitals in an atom (e.g., [tex]1s[/tex]) are denoted with:

There are two aspects to consider when finding the electron configuration of an atom:

The [tex]s[/tex] orbital in each shell could hold up to [tex]2 \times 1 = 2[/tex] electrons (one [tex]s\![/tex] orbital per shell, with up to two electrons.)

The [tex]p[/tex] orbitals in each shell could hold up to [tex]2 \times 3 = 6[/tex] electrons (three [tex]p\![/tex] orbitals per shell, with up to two electrons in each orbital.)

The [tex]d[/tex] orbitals in each main shell could hold up to [tex]2 \times 5 = 10[/tex] electrons (five [tex]d\![/tex] orbitals per shell, with up to two electrons in each orbital.)

Refer to the order in which the orbitals are filled (Aufbau principle.)

All four electrons of Beryllium are thus assigned to the [tex]1s[/tex] and [tex]2s[/tex] orbitals. In a ground-state Beryllium atom, orbitals [tex]2p[/tex] and beyond would contain no electrons.

Notation:

Write the non-empty orbitals in the order by which they are filled:

[tex]1s^2\, 2s^2[/tex].

Answer:

A) 1.72 atm

Explanation:

Dalton's Law of Partial Pressures

[tex]P_{t} = P_{1} + P_{2} + P_{3} ....[/tex]

4.43 atm = 1.23 atm + 1.48 atm + x

x = 4.43 atm - (1.23 atm + 1.48 atm)

x = 1.72 atm

Answer:

see below

Explanation:

1)  chem rxn    compound   molecule   covalent   ions    ionic

2) 2 hydrogen  one oxygen       H2O    covalent

3) is always liq

Answer:

Explanation: Sodium Nitroprusside, whose molecular formula is  • 2H2O, and whose molecular weight is 297.95. Dry sodium nitroprusside is a reddish-brown powder, soluble in water.

Answer:

71.6 g of Ru(CO)₅ is the maximum mass that can be formed.

The limiting reactant is Ag

Explanation:

The reaction is:

RuI₃ (s) + 5CO (g) + 3Ag (s) → Ru(CO)₅ (s) + 3AgI (s)

Firstly we determine the moles of each reactant:

169 g . 1mol /481.77g = 0.351 moles of RuI₃

58g . 1mol /28g = 2.07 moles of CO

96.2g . 1mol/ 107.87g = 0.892 moles

Certainly, the excess reactant is CO, therefore, the limiting would be Ag or RuI₃.

3 moles of Ag react to 1 mol of RuI₃

Then 0.892 moles of Ag may react to (0.892 . 1) /3 = 0.297 moles

We have 0.351 moles of iodide and we need 0.297 moles, so this is an excess. In conclussion, Silver (Ag) is the limiting.

1 mol of RuI₃ react to 3 moles of Ag

Then, 0.351 moles of RuI₃ may react to (0.351 . 3) /1 = 1.053 moles

It's ok, because we do not have enough Ag. We only have 0.892 moles and we need 1.053.

5 moles of CO react to 3 moles of Ag

Then, 2.07 moles of CO may react to (2.07 . 3) /5 = 1.242 moles of Ag.

This calculate confirms the theory.

Now, we determine the maximum mass of Ru(CO)₅

3 moles of of Ag can produce 1 mol of Ru(CO)₅

Then 0.892 moles may produce (0.892 . 1) /3 = 0.297 moles

We convert moles to mass → 0.297 mol . 241.07g /mol = 71.6 g

Answer:

all of the above

Explanation

Answer:

There are 0.379 moles of Ca in the given sample.

Explanation:

Hey there!

We're given that we have 15.2 grams of Ca (Calcium). We need to convert grams to moles.

There are many different conversion types for moles. A few examples are:

There are really endless possibilities for conversion factors. Since we want to find the number of moles in a certain sample, we first need to define what a mole is.

A mole is one unit of a certain item. For instance, one cup would be equivalent to one mole. Moles are simply a hypothetical unit in chemistry that act as a placeholder.

Now, how do we find the number of moles?

We know that a mole of something is one of that substance. In this case, we're referring to one atom of Calcium.

Therefore, we need to reference a periodic table to understand what the mass of one atom of calcium is equivalent to. I'll be using the official AP Chemistry periodic table as issued by the College Board.

When we reference the periodic table, we see the mass of one atom of calcium is equivalent to 40.08 amu (atomic mass units).

We learn in chemistry that we can use the terms amu and grams interchangeably, so we have learned that one mole of calcium is equivalent to 40.08 grams.

How do we work this out?

Now, we need to find out how many moles are in 15.2 grams of calcium. We can use dimensional analysis to work this out.

Our starting unit will be 15.2 grams of Ca.

We want to convert this into moles, so we need to cancel out our grams value. Additionally, since we know that we have 40.08 grams of Ca in one mole, we can set these up as two ratios:

These ratios can be used to express the relationship between the moles of calcium and the mass of one calcium atom. However, we need our value of grams to cancel out, so since we will be using cross multiplication in our dimensional analysis, we need to use the ratio with grams on the bottom.

Now that we have selected our ratio, we can set up a multiplication problem of our two ratios:

[tex]\displaystyle \text{15.2 grams Ca} \times \frac{\text{1 mole Ca}}{\text{40.08 grams Ca}}[/tex]

We assume that we have a denominator of 1 below 15.2 grams Ca.

Now, we perform our multiplication.

[tex]\displaystyle \frac{\text{15.2 grams Ca} \ \times \ \text{1 mole Ca}}{\text{40.08 grams Ca}}[/tex]

We see that our remaining unit is going to be mole(s) Ca, so we can go ahead and drop our grams Ca unit.

[tex]\displaystyle \frac{\text{15.2} \ \times \ \text{1 mole Ca}}{\text{40.08}}[/tex]

Now, we need to simplify a little bit.

[tex]\displaystyle \frac{\text{15.2}}{\text{40.08}} = \text{? moles Ca}[/tex]

Finally, let's divide our fraction and evaluate our equation to find the value of moles Ca.

[tex]\displaystyle \frac{15.2}{40.08} = \text{0.379241517 moles Ca}[/tex]

Are we done yet?

Not just yet! To complete our work, we need to find the number of significant figures we can use. We are given two values in which we can use to judge how many significant figures we are limited to.

In chemistry, we always use the least number of significant figures for precision calculations, so we need to round our answer to three significant figures.

[tex]0.379241517 \approx 0.379[/tex]

Therefore, there are approximately 0.379 moles of Ca in the given sample.

Answer:

(d) Why is the fuel cell in Question (c) described as an alkaline fuel cell? (e) Another type of fuel cell uses methanol instead of hydrogen.

Explanation:

Answer:

Prism B

Explanation:

Answer:

The optical properties of a material define how it interacts with light. The optical properties of matter are studied in optical physics, a subfield of optics. Wiki.pedia

Explanation:

Answer:

2.41x10²¹ atoms

Explanation:

First we calculate the mass of nickel in the coin, using the given mass and percent composition:

Then we convert 0.2355 grams of nickel to moles, using its molar mass:

Finally we convert moles into number of atoms, using Avogadro's number:

Answer:

The answer is "[tex]\bold{HClO_3 > HClO_2 >HClO > HBrO}[/tex]"

Explanation:

We arrange oxoacids to decrease the intensity of acids in this question. Or we may conclude all this from strongest to weakest acids they order oxoacids, that's why above given order is correct.

Answer:

J 9. , indicates the most sudden change in temperature