James made a poster showing the two body systems that regulate a person's pulse. Which two systems did james represent on his poster? F nervous and circulatory G resiratoty and endocrine systems H circular and digestive system I digestive and nervous system

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:

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:

Yes.

Explanation:

Yes, this method is accurate just as the slow titration because in both type of titrations we want to measure the point at which the indicator change the colour of the solution. Both fast and slow titrations are the same in their function i.e. both tell us the point or the amount at which the indicator change the colour of the solution so we can conclude from this discussion that fast titration gives the same result just as the slow titration.

Answer:

Sally's average speed is 0.5 km/min

Explanation:

speed=distance/time

so, 5km/10min=0.5 km/min

Answer:

Performance Tasks 188; Instructional Videos 75

Explanation:

Answer: The scientific method is an empirical method of acquiring knowledge that has characterized the development of science since at least the 17th century. It involves careful observation, applying rigorous skepticism about what is observed, given that cognitive assumptions can distort how one interprets the observation.

Explanation:

Hope this helps. :)

Answer: Balanced molecular equation :

[tex]2Na_3PO_4(aq)+3(CH_3COO)_2Zn(aq)\rightarrow 6CH_3COONa(aq)+Zn_3(PO_4)_2(s)[/tex]

Total ionic equation:

[tex]6Na^+(aq)+3PO_4^{2-}(aq)+6CH_3COO^-(aq)+3Zn^{2+}(aq)\rightarrow 6CH_3COO^-(aq)+6Na^+(aq)+Zn_3(PO_4)_2(s)[/tex]  

The net ionic equation:

[tex]2PO_4^{3-}(aq)+3Zn^{2+}(aq)\rightarrow Zn_3(PO_4)_2(s)[/tex]

Explanation:

Complete ionic equation : In complete ionic equation, all the substances that are strong electrolyte are present in an aqueous state as ions.

Net ionic equation : In the net ionic equations, we are not include the spectator ions in the equations.

Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.

When sodium phosphate and zinc acetate then it gives zinc phosphate and sodium acetate as  product.

The balanced molecular equation will be,

[tex]2Na_3PO_4(aq)+3(CH_3COO)_2Zn(aq)\rightarrow 6CH_3COONa(aq)+Zn_3(PO_4)_2(s)[/tex]

The total ionic equation in separated aqueous solution will be,

[tex]6Na^+(aq)+2PO_4^{3-}(aq)+6CH_3COO^-(aq)+3Zn^{2+}(aq)\rightarrow 6CH_3COO^-(aq)+6Na^+(aq)+Zn_3(PO_4)_2(s)[/tex]

In this equation, and  are the spectator ions.

By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.

The net ionic equation will be,

[tex]2PO_4^{3-}(aq)+3Zn^{2+}(aq)\rightarrow Zn_3(PO_4)_2(s)[/tex]

Answer:

c. 10–14[H3O+]

Explanation:

On a calculator, calculate 10-8.34, or "inverse" log ( - 8.34). Example: What is the pOH of a solution that has a hydroxide ion concentration of 4.82 x 10-5 M? The hydroxide ion concentration can be found from the pOH by the reverse mathematical operation employed to find the pOH.

Answer:

72.4%

Explanation:

Step 1: Write the balanced equation

2 Cu + S ⇒ Cu₂S

Step 2: Calculate the theoretical yield, in moles, from 0.0970 moles of Cu

The molar ratio of Cu to Cu₂S is 2:1.

0.0970 mol Cu × 1 mol Cu₂S/2 mol Cu = 0.0485 mol Cu₂S

Step 3, Convert the theoretical yield to mass

The molar mass of Cu₂S is 159.16 g/mol.

0.0485 mol × 159.16 g/mol = 7.72 g

Step 4: Calculate the percent yield

We will use the following expression.

%yield = experimental yield/theoretical yield × 100%

%yield = 5.59 g/7.72 g × 100% = 72.4%

The name of the given alkene is 2-methyl-1-propene. The correct option is A.

Alkenes are inorganic compounds. They are the series of hydrocarbons, that are formed by carbon-carbon double bonds. To find out alkenes, you have to see that the number of hydrogen atoms is always double the number of carbons.

Propene is an unsaturated compound, which is the second-simplest compound, and it contains a single double bond, and it is a colorless gas and has a texture of petroleum jelly.

CH₃C = CH₂

I

CH₃

Here, the three CH₃ are shown in the diagram, so it will be the methyl because it contains 3 CH₂, and now see the propene means one double bond and four carbon atoms. So it will be the 2-methyl-1-propene.

Thus, the correct option is A. 2-methyl-1-propene.

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Answer:

J 9. , indicates the most sudden change in temperature

Answer:

id k exactly what your asking

Explanation:

Answer:

C) Organic Weathering

Explanation:

Heat and Cold

And if some people start reporting and making fun of me in this answer don't listen to them.

They are hunting me down.

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]

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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:

1

Explanation:

Let's write the equation first:

[tex]C_{4}H_{10} + \frac{13}{2} O_{2} -> 4 CO_2 +5 H_{2}O[/tex]

So 1 mole of butane reacts to give 4moles of Carbon diOxide.

thus , 0.25 mole of butane will react to give = 4 * 0.25= 1 mole Carbon diOxide

Answer:

[tex]53.55gNO[/tex]

Explanation:

Hello there!

In this case, according to the given chemical reaction, it is possible for us to calculate the produced grams of nitrogen monoxide by starting with 25.0 g of nitrogen via their 1:2 mole ratio and the molar masses of 30.1 g/mol and 28.02 g/mol, respectively and by some stoichiometry:

[tex]=25.0gN_2*\frac{1molN_2}{28.02gN_2}*\frac{2molNO}{1molN_2}*\frac{30.01 gNO}{1molNO}\\\\=53.55gNO[/tex]

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Answer:

21883.75 Joules are required to melt the ice!

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.

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Answer:

b

Explanation:

i know

Answer:

1. 2Al + Cl2 = Al2Cl2

2 TiCl4 + 2Na = Ti + 2NaCl2

3. H2O2 = H2O + O2

4. Na2S + 2HCl = H2S + 2NaCl

5. Mg(OH)2 + 2HCl = MgCl2 + 2H2O

1. 3O2 = 2O3

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.

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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

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:

N2 + H20

Explanation:

chemical equation balancer