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Serggg [28]
3 years ago
14

A piece of potassium metal is added to water in a beaker. The reaction that takes place is 2K(s) 2H20(/) ..... 2KOH(aq) H2(g) Pr

edict the signs of w, q, liU, and /iH
Chemistry
1 answer:
kakasveta [241]3 years ago
4 0

Answer:

Explanation:

The given reaction is exothermic . So ΔH is negative .

Gas is evolving so work done by gas is positive or w is positive.

Change in internal energy that is ΔU is negative.

q = u - w

u is negative , w is positive so q is negative .

You might be interested in
Why is a thermos considered a (mostly) closed system? Question 3 options: different types of liquids stay hot thermoses come in
cestrela7 [59]

Answer:

Different types of hot or cold items can be stored in a thermos and power cannot enter or exit the system when the thermos lid is tightly closed

Explanation:

Closed systems are those that do not interact or do not exchange energy with the environment that surrounds them, that is why internal temperatures and conditions are maintained.

The human body is an open system, that is, it would be the opposite of the thermos since we constantly exchange energy with the environment through sweating, emission of gases, urine, feces, and the ingestion of food.

Thermoses are systems specially created to maintain a medium, it will be maintained if its lid is hermetically closed to prevent heat leakage or entry in situations of cold fluids.

4 0
3 years ago
Just wanted to make sure I have the right idea.
Rasek [7]

Explanation:

yes you got the right idea

4 0
3 years ago
1. It has been suggested that pain results from a change in the pH of solutions that surround nerves in the body.
Akimi4 [234]

Answer:

See Explanation

Explanation:

According to the question, it is established that the pain caused by a lot of insect bites owes to the acidity of the insect bites.

If this is true, then there is an urgent need to neutralize the acidic insect bite using a basic substance.

Hence the pH of the creams used to treat insect bites should be basic(having a high pH).

2. The compound methene can not exist because it is supposed to be derived from the alkane called methane which contains only one carbon atom.

In order to form an alkene, there must be a double bond between two carbon atoms. This is not possible because there is only one carbon atom in the hypothetical methene. Hence,  a compound named methene cannot exist.

3 0
3 years ago
What is the frequency of radiation whose wavelength is 2.25 X 10^-5cm?
Semenov [28]

Answer:

1.25 x 10^15Hz

Explanation:

c = frequency x wavelength

c is the speed of light, which is equal to 3.00 x 10^8 m / s

frequency = c /wavelength

= (3.00 x 10^8m /s) / (2.40 x 10^-5 cm x 1 m /100cm)

= (3.00 x 10^8 m/s) / 2.40 x 10^-7m

= 1.25 x 10^15/s 1 / s = 1Hz

So, the Frequency = 1.25 x 10^15Hz

I hope this helped :)

3 0
3 years ago
Combustion analysis of toluene, a common organic solvent, gives 3.52 mg of co2 and 0.822 mg of h2o. if the compound contains onl
IRISSAK [1]
<span>C7H8 First, lookup the atomic weight of all involved elements Atomic weight of carbon = 12.0107 Atomic weight of hydrogen = 1.00794 Atomic weight of oxygen = 15.999 Then calculate the molar masses of CO2 and H2O Molar mass CO2 = 12.0107 + 2 * 15.999 = 44.0087 g/mol Molar mass H2O = 2 * 1.00794 + 15.999 = 18.01488 g/mol Now calculate the number of moles of each product obtained Note: Not interested in the absolute number of moles, just the relative ratios. So not going to get pedantic about the masses involved being mg and converting them to grams. As long as I'm using the same magnitude units in the same places for the calculations, I'm OK. moles CO2 = 3.52 / 44.0087 = 0.079984 moles H2O = 0.822 / 18.01488 = 0.045629 Since each CO2 molecule has 1 carbon atom, I can use the same number for the relative moles of carbon. However, since each H2O molecule has 2 hydrogen atoms, I need to double that number to get the relative number of moles for hydrogen. moles C = 0.079984 moles H = 0.045629 * 2 = 0.091258 So we have a ratio of 0.079984 : 0.091258 for carbon and hydrogen. We need to convert that to a ratio of small integers. First divide both numbers by 0.079984 (selected since it's the smallest), getting 1: 1.140953 The 1 for carbon looks good. But the 1.140953 for hydrogen isn't close to an integer. So let's multiply the ratio by 1, 2, 3, 4, ..., etc and see what each new ratio looks like (Effectively seeing what 1, 2, 3, 4, etc carbons look like) 1 ( 1 : 1.140953) = 1 : 1.140953 2 ( 1 : 1.140953) = 2 : 2.281906 3 ( 1 : 1.140953) = 3 : 3.422859 4 ( 1 : 1.140953) = 4 : 4.563812 5 ( 1 : 1.140953) = 5 : 5.704765 6 ( 1 : 1.140953) = 6 : 6.845718 7 ( 1 : 1.140953) = 7 : 7.986671 8 ( 1 : 1.140953) = 8 : 9.127624 That 7.986671 in row 7 looks extremely close to 8. I doubt I'd get much closer unless I go to extremely high integers. So it looks like the empirical formula for toluene is C7H8</span>
7 0
3 years ago
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