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3 years ago

15

Frank wants to make a simple electromagnet. Which of these does Frank need to have to create the electromagnet? A. iron filings

B. light bulb C. battery D. magnet

2 answers:

Helga [31]3 years ago

6 0

C
He needs an battery to make the simple electromagnet

Jobisdone [24]3 years ago

6 0

C. battery because the pulse cant go with any of the other answers

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A 25.0 L tank of nitrogen gas is at 25 oC and 2.05 atm . If the temperature stays at 25 oC and the volume is decreased to 14.5 L

NeTakaya

Answer:

$\boxed {\boxed {\sf P_2 \approx 3.53 \ atm}}$

Explanation:

In this problem, the temperature stays constant. The volume and pressure change, so we use Boyle's Law. This states that the pressure of a gas is inversely proportional to the volume. The formula is:

$P_1V_1=P_2V_2$

Now we can substitute any known values into the formula.

Originally, the gas has a volume of 25.0 liters and a pressure of 2.05 atmospheres.

$25.0 \ L * 2.05 \ atm = P_2V_2$

The volume is decreased to 14.5 liters, but the pressure is unknown.

$25.0 \ L * 2.05 \ atm = P_2 * 14.5 \ L$

Since we are solving for the new pressure, or P₂, we must isolate the variable. It is being multiplied by 14.5 liters and the inverse of multiplication is division. Divide both sides by 14.5 L .

$\frac {25.0 \ L * 2.05 \ atm }{14.5 \ L}=\frac{P_2 *14.5 \ L}{14.5 \ L}$

$\frac {25.0 \ L * 2.05 \ atm }{14.5 \ L}= P_2$

The units of liters cancel.

$\frac {25.0 * 2.05 \ atm }{14.5 }=P_2$

$\frac {50.25\ atm }{14.5 }=P_2$

$3.53448276 \ atm = P_2$

The original values of volume and pressure have 3 significant figures, so our answer must have the same.

For the number we found, that is the hundredth place.

3.53448276

The 4 in the thousandth place (in bold above) tells us to leave the 3 in the hundredth place.

$3.53 \ atm \approx P_2$

The new pressure is approximately <u>3.53 atmospheres.</u>

8 0

3 years ago

Now, Johnny the pool guy must add enough Na2CO3 to get the pH back up to 7.60. How many grams of Na2CO3 does Johnny need to add

vaieri [72.5K]

Answer:

m = 3.4126 g

Explanation:

First, the question is incomplete but I already put in the comments the rest of the question.

Let's solve the first two questions, and then the actual question you are asking here to give you a better explanation of how to do it.

1) We need the volume of the pool, in this case is easy. Assuming the pool is rectangular, we use the volume of a parallelepiped which is the following:

V = h * d * w

We have the data, but first we will convert the feet to centimeter. This is because is easier to work the volume in cm³ than in feet.

So the height, width and depth of the pool in centimeter are:

h = 32 * 30.48 = 975.36 cm

w = 18 * 30.48 = 548.64 cm

d = 5.3 * 30.48 = 161.54 cm

Now the volume:

V = 975.36 * 548.64 * 161.54

V = 86,443,528.79 cm³ or 86,443,528.79 mL or 86,443.5 L

2) If the pool has a pH of 6.4, the concentration of H+ can be calculated with the following expression:

[H+] = antlog(-pH) or 10^(-pH)

Replacing we have:

[H+] = 10^(-6.4)

[H+] = 3.98x10^-7 M

3) Finally the question you are asking for.

According to the reaction:

Na2CO3 + H+ → 2Na+ + HCO3−

We can see that there is ratio of 1:1 between the H+ and the Na2CO3, so, if we have initially a concentration of 3.98x10^-7 M, the difference between the new concentration of H+ and the innitial, will give the concentration to be added to the pool to raise the pH. Then, with the molecular weight of Na2CO3 (105.98 g/mol) we can know the mass needed.

The new concentration of [H+] is:

[H+] = 10^(-7.6) = 2.58x10^-8 M

The difference of both [H+] will give concentration of Na2CO3 used:

3.98x10^-7 - 2.58x10^-8 = 3.73x10^-7 M

The moles:

moles = 3.73x10^-7 * 86,443.5 = 0.0322 moles

Finally the mass:

m = 0.0322 * 105.98

m = 3.4126 g

5 0

3 years ago

Answer the following stoichiometry question:

labwork [276]

Answer:

Mass = 684.2 g

Explanation:

Given data:

Moles of Aluminium = 25.36 mol

Mass of Al = ?

Solution:

Formula:

Number of moles = mass/ molar mass

Mass = number of moles × molar mass

Molar mass of Aluminium = 27 g/mol

Now we will put the values:

Mass = 25.36 mol × 26.98 g/mol

Mass = 684.2 g

4 0

3 years ago

What is the mass percent of calcium chloride if 57 g of CaCl2 is<br> dissolved in 334 g of water?

Zarrin [17]

Answer:

Solubility in water Anhydrous: 74.5 g/100 mL (20 °C) Hexahydrate: 49.4 g/100 mL (−25 °C) 59.5 g/100 mL (0 °C) 65 g/100 mL (10 °C) 81.1 g/100 mL (25 °C) 102.2 g/100 mL (30.2 °C) α-Tetrahydrate: 90.8 g/100 mL (20 °C) 114.4 g/100 mL (40 °C) Dihydrate: 134.5 g/100 mL (60 °C) 152.4 g/100 mL (100 °C)

6 0

3 years ago

How to solve the chemical formula for Calcium Chlorate

san4es73 [151]

Answer:

Ca(ClO3)2

Explanation:

The chemical formula of calcium chlorate is Ca(ClO3)2, which means in this molecule, Ca2+ ion is bonded to two ClO3- ions. So the formula can be expended to O3Cl-Ca-ClO3, or CaCl2O6 (basically times the numbers of the elements inside the bracket by the number outside the bracket.

3 0

3 years ago