Which of the following is an exothermic reaction?

a solid to a liquid

a gas change to a liquid

a liquid to a gas

a solid to a gas

Answers

Answer 1
i’m pretty sure it’s b !
Answer 2

Answer:

liquid to gas

Explanation:

when boiling water when evaporating heat is given out


Related Questions

Sally rides her bike to the store to get some Skittles. The store is 5 km
away. If it takes her 10 minutes to get to the store what is her average
speed?

0.5 km/hr
0.5 mph
0.5 km/min
5 km/min

Answers

Answer:

Sally's average speed is 0.5 km/min

Explanation:

speed=distance/time

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

How many moles are in 454 grams of dinitrogen trioxide (N2O3) ?

Answers

Answer:

5.97 mol

Explanation:

To find the number of moles when given the mass of a substance, we divide the mass of the sample by its molar mass.

so, we get,

nN203 = 454 g / 76.01 g /mol

= 5.97 mol

Is carbonic acid (H2CO3) soluble in water?

Answers

Answer:

it is soluble in water

Explanation:

mark brainliest pliiz cutee:)

Yes it is soluble in water

A chemistry student is given 3.00 L of a clear aqueous solution at 17 C . He is told an unknown amount of a certain compound X is dissolved in the solution. The student allows the solution to cool to 17 C . The solution remains clear. He then evaporates all of the water under vacuum. A precipitate remains. The student washes, dries and weighs the precipitate. It weighs 0.15 kg . Using the above information can you calculate the solubility, X, in water at 17 C.

Answers

Answer:

The right approach is "50 g/l".

Explanation:

The given values are:

Mass or solute or precipitation,

= 0.15 kg

on converting it into "g", we get

= [tex]0.15 \ kg\times \frac{1000 \ g}{1 \ kg}[/tex]

= [tex]150 \ g[/tex]

Volume of solution,

=  3.00 L

Now,

The solubility of X will be:

=  [tex]\frac{Mass \ of \ X}{Volume \ of \ solution}[/tex]

On substituting the values, we get

=  [tex]\frac{150}{3}[/tex]

=  [tex]50 \ g /l[/tex]

that create stars, scientists understand more and more about how the universe came into existence. The ne
little green men up in space, think about all the great astronomers who have studied the night sky in search
Question 1
Using the information in the passage, rank the types of galaxies by their ability to form new stars, from most to
least activity
.
Elliptical, spiral, irregular
Irregular, elliptical, spiral
Spiral, irregular, elliptical
Irregular, spiral, elliptical
Son

Answers

Answer:

i would have to read the artical but i would say the first one

Explanation:

A 5.0 g sample of a pesticide was decomposed with metallic sodium in alcohol, and the liberated chloride ion was precipitated with AgCl. Express the results of this analysis in terms of percent DDT (C14H9Cl5, molar mass, 354.72 g/mol)) based on the recovery of 0.1606 g of AgCl

Answers

Answer:

1.59%

Explanation:

First, we convert 0.1606 g of AgCl into moles, using its molar mass:

0.1606 g ÷ 143.32 g/mol = 1.12x10⁻³ mol AgCl

Then we convert the calculated moles of Cl (equal to AgCl moles) into moles of DDT:

1.12x10⁻³ mol Cl * [tex]\frac{1molDDT}{5molCl}[/tex] = 2.24x10⁻⁴ mol DDT

Now we convert 2.24x10⁻⁴ moles of DDT into grams, using its molar mass:

2.24x10⁻⁴ mol DDT * 354.48 g/mol = 0.0794 g

Finally we calculate the percentage of DDT in the sample:

0.0794 g / 5.0 * 100% = 1.59%

Calculate the pH of a 0.010 M NaNO2 solution.

Answers

Answer:

Calculate the pH of 0.010 M HNO2 solution. The K, for HNO2 is 4.6 x 104

Answer: pH = 2.72

1.Why do you think the agricultural revolution led to more population growth?

Answers

Answer:

The agricultural revolution increased agricultural production and technological advancements. I think this led to population growth because the increase in labor and the increase in technologies increased human deveolpment. The revolution also allowed farmers to grow and produce more food and transport it to where it was needed.

Explanation:

how many atoms of carbon are in a diamond with a mass of 0.568 g?

Answers

Answer:

There are 2.85 x 10^22 atoms of carbon in a diamond with a mass of 0.568 g.

Hope this helps! :)

Oxalic Acid, a compound found in plants and vegetables such as rhubarb, has a mass percent composition of 26.7% C, 2.24% H, and 71.1% O. Oxalic acid can interfere with respiration and cause kidney or bladder stones. If a large quantity of rhubarb leaves is ingested, the oxalic acid can be toxic. The lethal dose (LD50) in rats for oxalic acid is 375 mg/kg. Rhubarb leaves contain about 0.5% by mass of oxalic acid. (Show your work, using the insert equation tool :) What is the empirical formula of oxalic acid

Answers

Answer:

HCO₂

Explanation:

From the information given:

The mass of the elements are:

Carbon C = 26.7 g;     Hydrogen H = 2.24 g     Oxygen O = 71.1 g

To determine the empirical formula;

First thing is to find the numbers of moles of each atom.

For Carbon:

[tex]=26.7 \ g\times \dfrac{1 \ mol }{12.01 \ g} \\ \\ =2.22 \ mol \ of \ Carbon[/tex]

For Hydrogen:

[tex]=2.24 \ g\times \dfrac{1 \ mol }{1.008 \ g} \\ \\ =2.22 \ mol \ of \ Hydrogen[/tex]

For Oxygen:

[tex]=71.1 \ g\times \dfrac{1 \ mol }{1.008 \ g} \\ \\ =4.44 \ mol \ of \ oxygen[/tex]

Now; we use the smallest no of moles to divide the respective moles from above.

For carbon:

[tex]\dfrac{2.22 \ mol \ of \ carbon}{2.22} =1 \ mol \ of \ carbon[/tex]

For Hydrogen:

[tex]\dfrac{2.22 \ mol \ of \ carbon}{2.22} =1 \ mol \ of \ hydrogen[/tex]

For Oxygen:

[tex]\dfrac{4.44 \ mol \ of \ Oxygen}{2.22} =2 \ mol \ of \ oxygen[/tex]

Thus, the empirical formula is HCO₂

what do protons determine about an element

Answers

The number of protons in an atoms determines the atoms identity. Electrons determine the electrical charge.

Answer:

The number of protons in one atom of an element determines the atom's identity, and the number of electrons determines its electrical charge. The atomic number tells you the number of protons in one atom of an element. It also tells you the number of electrons in a neutral atom of that element.

Explanation:

Ozone is three oxygen atoms bonded together. It can sometimes be smelled in the air after a thunderstorm. the smell is a result of

Answers

Ozone gas can be smelled in the air after a thunderstorm as a result of  reactions between oxides of nitrogen and volatile organic compounds.

How ozone gas be smelled?

Ozone gas can be produced due to chemical reactions between oxides of nitrogen and volatile organic compounds. This reaction occurs when pollututed gas is emitted from vehicles react and other activities with each other in the presence of sunlight.

So we can canclude that Ozone gas can be smelled in the air after a thunderstorm as a result of  reactions between oxides of nitrogen and volatile organic co

Learn more about ozone here: https://brainly.com/question/520639

4) Which of the following can cause erosion?
- Glaciers, wind, and animals
- Acid rain, animals, and ice wedging
- Wind, water, glaciers
- Glaciers, wind, and acid rain

5) Which factors affect the rate of weathering?
- Temperature, ocean currents, and tides
- Type of rock and amount of precipitation
- Type of plants and animals
- Amount of sunlight

Answers

Water, air, and even ice are fluids because they tend to flow from one place to another due to the force of gravity.

Rainfall and temperature can affect the rate in which rocks weather. High temperatures and greater rainfall increase the rate of chemical weathering. 2. Rocks in tropical regions exposed to abundant rainfall and hot temperatures weather much faster than similar rocks residing in cold, dry regions.

How does photosynthesis happen? (Also can anyone Pay Pal me 2 more dollars for school supplies.

Answers

Explanation:

make me brainy least pkz

Calculate the wavelength (in nm) of the blue light emitted by a mercury lamp with a frequency of 6.32 × 1014 Hz.

Answers

Answer:

474 nm or 4.74 x 10^2 nm

Explanation:

c = λv

c (speed of light) = 2.998 x 10^8 m/s

λ = ?

v = 6.32 × 1014 Hz = 6.32 × 1014 1/s

2.998 x 10^8 m/s = (λ)(6.32 × 10^14 1/s)

λ = (2.998 x 10^8 m/s) / (6.32 × 10^14 1/s)

λ = 4.74 x 10^-7 m

λ = 4.74 x 10^-7 m x (1 x 10^9 nm/1 m) = 474 nm

Which among the following is not required in the synthesis of fatty acids.
A). Acetyl-CoA
B). Biotin
C). Carbon iv oxide
D). NADH

Answers

Answer:

D). NADH

Explanation:

.....plllzzz heeelp me fast?? ​

Answers

Answer:

Explanation:

It is 11

It’s 11 dndndnenddnnenrfjdnnrfnnd

Which of the following is a period 4 representative element?
A. C
B. An
C. Ti
D. K



Answers

[tex]\huge{\mathbb{\tt { QUESTION↓}}}[/tex]

Which of the following is a period 4 representative element?

O A. C

O B. An

O C. Ti

O D. K

[tex]\huge{\mathbb{\tt {ANSWER↓}}}[/tex]

[tex]\color{blue}{\tt {A.C ( Carbon )}}[/tex]

[tex]{\boxed{\boxed{\tt { WHAT \: IS \: CARBON?}}}}[/tex]

Carbon (from Latin: carbo "coal") is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalen - making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust.

#CarryOnLearning

#LetsEnjoyTheSummer

→XxKim02xX

Plz help me well mark brainliest if correct!!

Answers

Answer:

A

Explanation:

Waxing means getting bigger.

Waning is.. you guessed it... the exact opposite.

Answer:

a

Explanation:

..........................

Predict the products for the reaction shown in the picture.
Fe(s) + CuCrO4(aq) —>

Answers

Answer:

After checking many websites as well

I haven't seen any answer for this reaction

While I found answers or other reactions

Therefore I think this reaction cannot occur

Please mark my answer as brainliest if you feel I helped you in any way :)

how many moles of ammonia can be formed from 4.0 mol H2

how many moles of hydrogen are required to form 8.0 mol NH3

how many moles of nitrogen are required to react with 6.0 mol H2

Answers

Answer: 1. 2.7 moles  of ammonia are formed

2. 12.0 moles  of hydrogen are required

3. 2.0 moles of nitrogen are required

Explanation:

The balanced chemical equation is:

[tex]N_2+3H_2\rightarrow 2NH_3[/tex]

According to stoichiometry:

3 moles of hydrogen form = 2 moles of ammonia

Thus 4.0 moles of hydrogen form =[tex]\frac{2}{3}\times 4.0=2.7moles[/tex] of ammonia

According to stoichiometry:

2 moles of ammonia are formed by = 3 moles of hydrogen

Thus 8.0 moles of ammonia are formed by  =[tex]\frac{3}{2}\times 8.0=12.0moles[/tex] of hydrogen

According to stoichiometry:

3 moles of hydrogen react with = 1 mole of nitrogen

Thus 6.0 moles of hydrogen react with =[tex]\frac{1}{3}\times 6.0=2.0moles[/tex] of nitrogen

Americium-241 undergoes radioactive decay to produce neptunium-237. Which particle needs to be added to this equation to show that the total numbers of neutrons and protons are not changed by the reaction?​

Answers

Answer:

alpha particle needs to be added to the equation.

Explanation:

Given;

atomic mass of Americium = 241

atomic mass of neptunium = 237

The difference in atomic mass of the radioactive elements given is calculated as;

241 - 237 = 4

The particle with atomic mass of 4 is alpha particle usually represented with helium atom.

Am²⁴¹ -----> He⁴ + Np²³⁷

Thus, alpha particle needs to be added to the equation.

Answer:

4/2 HE

Explanation:

a p e x!

Suppose that Laser A were to shine a beam of light straight into the left side of Prism A, and Laser B were to shine an identical beam of light straight into the left side of Prism B. Which prism would refract the light more? (Assume the sides of the two prisms are sloped the same.)

Answers

Answer:

Prism B

Explanation:

2. A chemical's flash point is the​

Answers

Flash point is the minimum temperature at which a liquid forms a vapor above its surface in sufficient concentration that it can be ignited.


1. The octane present in gasoline burns according to the following equation:

2 C8H18 + 25 O2 → 16 CO2 + 18 H2O

(a) How many moles of O2 are needed to react fully with 27.5 moles of octane?

Answers

Answer:

[tex]n_{O_2}=343.75molO_2[/tex]

Explanation:

Hello there!

In this case, according to the combustion of octane:

[tex]2C_8H_1_8+25O_2\rightarrow 16CO_2+18H_2O[/tex]

We can see there is a 2:25 mole ratio of octane to oxygen; therefore, we can calculate the moles of oxygen via the following stoichiometric factor:

[tex]n_{O_2}=27.5molC_8H_1_8*\frac{25molO_2}{2molC_8H_1_8} \\\\n_{O_2}=343.75molO_2[/tex]

Best regards!

In scientific notation, the number 0.00262 is expressed as

Answers

Answer:

2.62*10^-3

Explanation:

To do this by hand, you need to understand the rules of scientific notation.

Answer:

0.00262 in scientific notation is 2.62 x 10^-3

Which of the following elements will form positive ions? Check all
that apply.
Na
z
Cu
Br

Answers

Answer:

cu and Na

Explanation:

When an atom losses electrons this results in a positive charge. A positively charged ion is called a cation.

Sodium and copper will form positive ions. Sodium is a monovalent cation while copper is a divalent cation.

What are positive ions?

The ions which contain a positive charge it is called positive ions. The atomic number of sodium is 11. It contains (2, 8, 1) electrons. When it loses it's one electron it will be a positive ion.

Copper has valence electrons. When it loses its two valence electrons it will be a copper ion. There are two types of ions such as positive ions and negative ions.

Small molecules that have acquired a positive charge are known as positive ions. Positive ions are the predominant type of air pollution, including hazardous substances, pollen, mold, pet dander, and other dangerous chemicals.

Therefore, Sodium and copper will form positive ions. Sodium is a monovalent cation while copper is a divalent cation.

To learn more about positive ions, refer to the link:

https://brainly.com/question/269828

#SPJ5

For some transformation having kinetics that obey the Avrami equation (Equation 11.17), the parameter n is known to have a value of 2.3. If, after 145 s, the reaction is 50% complete, how long (total time) will it take the transformation to go to 88% completion

Answers

Answer:

t ≈ 235.47 secs

Explanation:

Calculate how long it will take the transformation to go to 88% completion

Given that Avrami equation ( y )= 1 - exp( - kt^n )

n = 2.3

t = 145 secs

reaction = 50%  after t = 145 secs

Reaction = 88%  after t = ?

attached below is a detailed solution

Plz help me I am timed!!

Answers

answer: i think it is C

what is one property of skim milk indicating that it is a colloidal dispersion?​

Answers

Answer:

it's dairy

Explanation

Other Questions
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