pls help me with thiss

Answer: Because percent solutions can be expressed in three different ways, it is imperative that the type of percent solution be explicitly stated. If this information is not provided, the end user is left to "guess" whether w/v %, w/w %, or v/v % was used. Each percent solution is appropriate for a number of different applications. For example, commercial aqueous reagents, such as concentrated acids and bases, are typically expressed as weight/weight % solutions. For example, commercially available concentrated hydrochloric acid (HCl) is 37% by weight (w/w %). On the other hand, many dilute solutions used for biological research are expressed as weight/volume % (e.g., 1% sodium dodecyl sulfate, SDS). Volume/volume % solutes are also common, and are used when pure solutes in liquid form are used. For example, a 70 % (v/v) solution of ethanol can be prepared by dissolving 70 mL of 100% (i.e., 200 proof) ethanol in a total solution volume of 100 mL.

Answer: D

Explanation:

The reason it is D is because a balanced chemical equation will always have the same number of atoms on both sides. In answer d, both sides have a total of 4 atoms, so it it balanced.

Answer:

See below

Explanation:

75 g * ( 90 - 23) C   *  1 cal / g-C

= 5025 cal     =    21 034 .7 J

Answer:

.224 M

Explanation:

To begin, we need to find the molar mass of Na2S

To find Molarity, we use the equation M=moles/Liters of solution

We are given grams, so we must divide by the molar mass of Na2S to find moles.

Now we use our Molarity equation:

After the complete neutralization reaction occurs, excess hydroxide ion is left unreacted and concentration of the hydroxide ion, [OH-] is 0.02 M.

The hydroxide ion concentration is the amount in moles of hydroxide ion in a solution.

The hydroxide ion concentration is written as [OH-].

The equation of the reaction is given below:

[tex]HBr(aq) + KOH(aq) \rightarrow KBr(aq) + H_2O(l) \\ [/tex]

1 mole of HBr reacts with 1 mole of KOH

Moles of HBr = 40 mL × 0.1 M = 4 mmmoles

Moles of KOH = 60 mL × 0.1 M = 6 mmoles

Moles of [OH-] = 6 - 4 = 2 mmoles

Volume of solution = 100 mL

[OH-] = 2mmoles/100 mL = 0.02 M

Therefore, the concentration of the hydroxide ion, [OH-] is 0.02 M.

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Answer:

The small bodies from which the planets formed are called planetesimals.

Benzene

Low denisty object than the water usually floats on the water.

Another example: orange peel which floats on water has density of about 0.84 g/cm³

Answer:

[tex][CaSO_4] = 2 mol/L[/tex]

Explanation:

[tex][CaSO_4] = \frac{3 mol}{1.5 L} = 2 mol/L[/tex]

Answer:

i think ionic?

Explanation:

hope this helps

Answer:

68.4 liters

Explanation:

PV = nR T       R = gas constant = .082057  L atm / K-mole

                        n = 10      T = 27C = 300.15 K

3.6 V = 10 * .082057 * 300.15      solve for V = 68.4 liters

Answer:

See below...

Explanation:

6.79 = 100 ( 1/2)^n    solve for n = number of half lives

3.88 half lives

3.88 * 24000 = 93 130.7 years

Ba(OH)2

HOPE IT HELPS...!!!

Answer:

D) alkaline

Explanation:

Answer:

1•323

Explanation:

mass of carbon=12

mass of oxygen=2*16=32

no of moles = 3/44

PV=nRT

V=(0.06818*8.31*288)/123.3*10^3

Answer:

Acetic acid is a weak electrolyte because its dissociation constant is small meaning there will be few ions in solution to conduct electricity.

Weak electrolyte are very less or partially ionized and strong electrolytes are completely ionized or 100% ionized. Ethanoic acid is weak electrolyte.

To determine whether the acid is strong electrolyte or weak electrolyte check whether it is completely ionize or partially ionized. The molecular formula of ethanoic is [tex]CH_3COOH[/tex] and ethanoic acid is also called acetic acid. Ethanoic acid is weak electrolyte because it does not dissociate very much.

The dissociation of ethanoic acid in water:

[tex]CH_{3}COOH_{(aq)} + H_{2} O_{(l)}[/tex] ⇄ [tex]CH_{3}COO^{-}_{(aq)} + H_{3}O^{+}_{(aq)}[/tex]

Thus, from above conclusion we can say that Ethanoic acid is weak electrolyte and the dissociation of ethanoic acid in water is:  [tex]CH_{3}COOH_{(aq)} + H_{2} O[/tex] ⇄ [tex]CH_{3}COO^{-}_{(aq)} + H_{3}O^{+}_{(aq)}[/tex]

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#SPJ2

Answer:

True.

Explanation:

Typically, cars have built in radios for the reason of not using your phone. That's why you connect it with bluetooth to call, text, and use personal music instead of listening to the ones on the radio.

Answer:

True

Explanation:

It is to keep us safe. So, we answer calls without having to take our hands off the wheel. Although it is unsafe for that aswell. The best thing to do is have 0 things that would keep you from having your eyes on the road.

Answer:

The answer is the heat is transferred from the ice to the coffee.

Explanation:

Hot molecules tend to transfer to colder molcules, which causes the ice to melt and makes the coffee colder.

Hope this helps! :)

The net ionic reaction for barium nitrate and lithium iodide showing the precipitation of barium iodide is given below:

[tex]Ba^{2+}(aq) + 2I^{-}(aq) \rightarrow BaI_2(s)[/tex]

A net ionic equation is an ionic equation which shows only the ions that have undergone both reduction and oxidation only without any spectator ions present.

The net ionic reaction for barium nitrate + lithium iodide is given below:

[tex]Ba^{2+}(aq) + 2I^{-}(aq) \rightarrow BaI_2(s)[/tex]

Therefore, net ionic reaction for barium nitrate and lithium iodide shows the precipitation of barium iodide.

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Answer:

2441.9 Joules

Explanation:

This is a sensible heat change problem.

Energy = Specific Heat Capacity x Mass x Change in Temperature

To find the change in temperature, you need to use this formula: Temperature Final - Temperature Initial.

234.3 - 137.0 = 97.3

Energy = 1.65 x 15.21 x 97.3

Multiply that equation, and you get your answer! I hope this helps!

Answer:

B

Explanation:

I think it might be B because if the student's hypothesis was incorrect why redo it and make sure the results are the same as last time if it was already incorrect before.

Answer:

Gulf Stream. The Gulf Stream is a warm surface ocean current which originates in the Gulf of Mexico and flows northeast across the Atlantic, driven by the prevailing southwest winds. It influences the climate of the UK and Northwest Europe by bringing with it humid mild air.

Answer:

D. Vent is the answer please

Answer:

I think it would be costly due to the fact that the gem is very rare and gorgeous. Also, the current prices are on average $3,000 per carat, so I would say that is pretty costly.

Explanation:

Hope this helps:)....if not then sorry for wasting your time and may God bless you:)

Answer:

Answer :

See below ~

Explanation :

1) No

2) Yes

3) No

Answer:

“You Asked” is a series where Earth Institute experts tackle reader questions on science and sustainability. Over the past few years, we’ve received a lot of questions about carbon dioxide — how it traps heat, how it can have such a big effect if it only makes up a tiny percentage of the atmosphere, and more. With the help of Jason Smerdon, a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory, we answer several of those questions here.

Since one pound (1.00 lb) of body fat is equivalent to approximately 3.488 x 10^3 kcal, then 27.9 miles must be covered to burn off one pound.

Energy is defined as the ability to do work. Now we are told that one pound (1.00 lb) of body fat is equivalent to approximately 3.488 x 10^3

kcal.

Hence;

If 125 kcal is burnt by running one mile

3.488 x 10^3 kcal is burnt by running x miles

x = 3.488 x 10^3 kcal * 1 mile/125 kcal

x = 27.9 miles

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