What clues indicate that a chemical reaction has occurred?


Choose all correct answers.


the formation of a new liquid


a color change


a temperature change


the formation of bubbles

Answers

Answer 1

Answer:

its probably all of the above, if not then it should be the formation of a new liquid, and a color change

Explanation:


Related Questions

A sample of lead released 2,744 J when it cooled from 90 to 19 °C. What was the
mass of the sample of lead? (The specific heat of lead is 0.129 J/g x °C)

Answers

Answer:

299.60 g

Explanation:

Use the formula q = mCΔT (q= heat, m= mass, c = specific heat for that specific substance, ΔT is change in temperature Final Temp - Initial Temp)

Released heat means it has negative sign.

q = mCΔT

-2744 = (mass) (0.129) (19-90)

mass= 299.60 g

Calculate the volume of 100. grams of oxygen gas (O₂) at 25.0°C and a pressure of 1.25 atm.

Answers

Ideal gas law states

PV = n(RT)

V is volume (L), P is pressure (atm), R is universal gas constant: 0.0821 L·atm/mol· K, n is number of moles, T is temperature in Kelvin

Here given:

[tex]\blacksquare[/tex] mass of O₂ : 100 gram

[tex]\blacksquare[/tex] moles: mass/molar mass = 100/32 = 3.125 moles

[tex]\blacksquare[/tex]  25.0 °C = (25+273.15) = 298.15 K

[tex]\blacksquare[/tex]  pressure: 1.25 atm

Volume:

[tex]\boxed{\sf V=\dfrac{nRT}{P}}[/tex]

[tex]\Rightarrow \sf V=\dfrac{(3.125 \ x \ 0.0821 \ x \ 298.15 )}{1.25}[/tex]

[tex]\Rightarrow \sf V=61.195 \ L[/tex]

[tex]\Rightarrow \sf V=61.2 \ L \ \ \ (rounded \ to \ nearest \ tenth)[/tex]

Additional Explanation:

Volume can be counted in multiple units.

In Liters: 61.2 Liters

In cubic meter: 0.061163 m³

In cubic centimeter: 61,163.5 cm³

Can Someone help me please…
1 How do scientists mfasure population and changes in

2 What causes populations and ecosystems to remain stable or to
change over time?

3 What factors affect populations within an ecosystem?

4 How do modest or drastic changes in ecosystems affect ecosystem
stability?

Answers

Answer:

1.Ecologists often estimate the size and density of. populations using quadrats and the mark-recapture method.

2. The two key components of ecosystem stability are resilience and resistance.

3.The availability of abiotic factors (such as water, oxygen, and space) and biotic factors (such as food) affect population

4. When the climate is changing in the colder direction it effects the planet in the opposite way than it does when it is changing in the warmer direction. Ad nauseam the contemporary, it’ll keep getting hotter and at a greater rate so the ecosystem is going to die.

What is the temperature, in degrees Celsius, of a substance with a temperature of 49K?

Answers

Answer:
The answer is -224C

Explanation:
When a temperature of 49K is converted into Degrees Celsius, it turns into -224C

An Glu amino acid is found in the core (interior) of a water-soluble FOLDED protein (meaning its happy there). What must happen to the pKa of its side-chain group

Answers

Glutamic amino acid is the non-essential amino acid and an excitatory neurotransmitter. When Glu is found in the core then the pKa of the side chain group increases.

What is pKa?

pKa is the acid strength or the estimate that shows whether the solution is weak or strong acid. pKa less than zero is a strong acid and portrays the bonding of the proton by the acids.

In the Glu amino acid, the value of the pKa of the side chain functional groups increases as the amino acid is found in the interior of the water-soluble folded protein structure.

Therefore, the pKa of the side-chain increases.

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What do you mean by cation and anion

Answers

[tex]\qquad\qquad\huge\underline{{\sf Answer}}[/tex]

Cations are ions that has a positive charge on it, and since it's a positive charge, it means that the ion has more protons than the number of electrons.

On the same contray, Anions are negatively charged particles having more electrons than protons in it, and hence bearing a negative charge.

property : non - alike ions attract each other by electrostatic force.

Answer:

Cations are positively-charged ions.

Anions are negatively-charged ions.

. Given the balanced equation representing a reaction:
Fe(s) + 2HCl(aq) → FeCl₂ (aq) + H₂(g)
This reaction occurs more quickly when powdered
iron is used instead of a single piece of iron of the
same mass because the powdered iron
A) acts as a better catalyst than the single piece of
iron
B) absorbs less energy than the single piece of iron
C) has a greater surface area than the single piece of
iron
D) is more metallic than the single piece of iron

Answers

Answer:

C

Explanation:

The powdered iron has a greater surface area than the single piece of metal, allowing reactions to be done faster.

It's NOT A because in the reaction Iron is a reactant NOT a catalyst

It's NOT B because it's completely irrelevant to the question

It's NOT D because it's also not relevant to the question at hand

How is Hess's law used to calculate the enthalpy of a reaction?
A. The enthalpy is obtained from the difference in final and initial reactions in a path.
B. Enthalpies from similar equations are substituted for unknown reaction enthalpies. C. The final equation in a reaction path provides the enthalpy for the desired reaction.
D. The desired enthalpy is obtained through adding intermediate reactions together.​

Answers

Considering the Hess's Law, the desired enthalpy is obtained through adding intermediate reactions together. (option D)

Hess's Law

Hess's law, also called Law can also be called Law of additivity of the enthalpies of reaction, it is a useful method when it is not possible to calculate the enthalpies of reaction from the enthalpies of formation, or in reactions in which the reaction enthalpy cannot be determined experimentally because it is very slow or very explosive.

Hess's law states that when reactants are converted to products, the enthalpy change is the same whether the reaction takes place in one step or in a series of steps.

In this way, Hess's Law determines that when a chemical reaction can be expressed as an algebraic sum of other reactions, its reaction enthalpy is equal to the sum of the enthalpies of the partial reactions. In this way, it allows thermochemical equations to be treated as algebraic equations, and can be added, subtracted, or multiplied by a number to find the desired thermochemical equation.

Summary

Hess's Law states that the sum of the ∆H of each stage of the reaction will give us a value equal to the ∆H of the reaction when it occurs in a single stage.

That is, the desired enthalpy is obtained through adding intermediate reactions together. (option D)

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What type of pollution is pictured here?

Answers

Answer:this air polluction here.

Explanation:

air and soil polluction

A fish has armored plates that enable it to handle the extreme pressure in the deepest, darkest aquatic ecosystem. Where is this fish adapted to live? a pond the open ocean the neritic zone an estuary.

Answers

Answer: B) the open ocean

Scientists hypothesize that Earth's first oceans were made of fresh water. How did oceans obtain fresh water?

Answers

Answer:

The oceans obtained freshwater from glaciers melting. The freshwater was then trapped into small places below waves, which could be a reason why there is not much freshwater in the world.

Treatment of Poison oak

Answers

Answer:

Apply cool compresses to the skin. Use topical treatments to relieve itching, including calamine lotion, oatmeal baths, Tecnu, Zanfel, or aluminum acetate (Domeboro solution). Oral antihistamines, such as diphenhydramine (Benadryl), can also help relieve itching.

Aluminum Oxide is formed when aluminum combines with oxygen in the air. How many grams of Al2O3 are formed when 23.6g of Al reacts completely with oxygen?

Answers

The amount of [tex]Al_2O_3[/tex] that would be formed will be 44.59 grams

Stoichiometric calculation

From the equation of the reaction:

[tex]4Al + 3O_2 --- > 2Al_2O_3[/tex]

The mole ratio of Al to  [tex]Al_2O_3[/tex] is 2:1

Mole of 23.6 g Al = 23.6/26.98 = 0.87 moles

Equivalent mole of  [tex]Al_2O_3[/tex] = 0.87/2 = 0.44 moles

Mass of 0.44 mole  [tex]Al_2O_3[/tex] = 0.44 x 101.96 = 44.59 grams

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If 6.3 moles of O2 and 8.15 moles of N2 are placed in a 65.1 L tank at a
temperature of 348 C, what will the pressure of O2?

Answers

Answer:

Partial pressure of O2 = 4.93 atm

Explanation:

PV = n RT        R = .082057 L-atm/mol-K

n = 6.3 + 8.15 = 14.45 moles

348 C = 621.15 K

P (65.1) = 14.45 ( .082057)(621.15) = 11.31 atm

Now the fraction of pressure from Oxygen is

   6.3 / (6.3+8.15)  * 11.31 = 4.93 atm

a gas exerts a pressure of 1.00 atm at 273 K. At what tempreture the gas exerts a pressure of 4.00 atm.

Answers

Considering Gay-Lussac's law, a gas exerts a pressure of 4.00 atm at 1,092 K.

Gay-Lussac's law

Gay-Lussac's law states that the pressure of a gas is directly proportional to its temperature: when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, gas pressure decreases.

Gay-Lussac's law can be expressed mathematically as follows:

[tex]\frac{P}{T}=k[/tex]

where P= pressure, T= temperature, k= Constant

This law states that the ratio of pressure to temperature is constant.

Studying an initial state 1 and a final state 2, it is fulfilled:

[tex]\frac{P1}{T1}=\frac{P2}{T2}[/tex]

Final temperature

In this case, you know:

P1= 1 atmT1= 273 KP2= 4 atmT2= ?

Replacing in Gay-Lussac's law:

[tex]\frac{1 atm}{273 K}=\frac{4 atm}{T2}[/tex]

Solving:

[tex]T2\frac{1 atm}{273 K}=4 atm[/tex]

[tex]T2=\frac{4 atm}{\frac{1 atm}{273 K}}[/tex]

T2= 1,092 K

Finally, a gas exerts a pressure of 4.00 atm at 1,092 K.

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Plan an investigation to examine the relationship between the amount of gas
and its volume. Identify the materials and write a procedure, identifying the
constants and variables. Conduct the investigation and record your
observations.

I can’t think of anything to use for this experiment and we aren’t told what to use so if anyone had any ideas for that I would really appreciate it

Answers

Answer:

You will need a Kukushili pressure cooker for this experiment. This pressure cooker will allow you to compress the gases and observe its volume.

Islam's message of peace if universal, as without it there can be no happiness
A. Good
B. Applicable to all the people in the world
C. Acceptable
D. None of these

Answers

ANSWER

B po yung ans:)

The pressure for 1.0 mol of a gas at 0oC in 3.0 L container is calculated to be 7.5 atm using the ideal gas equation (PV = nRT). The pressure of the gas is measured and found to be 7.1 atm. Which of the following best explains the reason for the discrepancies in the two values?

Answers

The best explanation would be that the temperature of the gas has dropped before measuring the pressure.

Relationship between temperature and pressure of gases

According to pressure law, the pressure of a gas is directly proportional to its temperature, provided the volume of the gas remains constant.

Thus, since the initial pressure of the gas was calculated to be 7.5 atm, the temperature of the gas must have dropped in order for the measured pressure to be 7.1 atm.

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The stigma on the underside of the leaf allows________to move in and out of the leaf

Answers

Answer:

The stigma on the underside of the leaf allows Gas and Water Vapour to move in and out of the leaf


9. An empty, massless cube is measured to have all sides equal to 11 cm. It is floating in water and will slowly be filled with sand
that has a density of 3.5 g/cm'. What volume of sand will cause the box to sink?

Answers

sink: w cube+w sand>Fb(buoyant force)

w cube = massless = 0

w sand>Fb

w sand > 1000 x 10 x (11/100)³

w sand > 13.31 N

ρgV sand > 13.31

3.5 x 10³ x 10 x V sand > 13.31

V sand = 13.31 : 3.5 x 10⁴ = 3.803 x 10⁻⁴ m³ = 380.3 cm³  

PLEASE HELP!!! HOW DO I DO THIS??
What is the Ka of a weak acid with a molarity of 0.333 and a pH of 4.6?

Answers

4.7 is the answer!

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What is the phase of water at 0.5 atm and 100°C?
Water
(liquid)
Water vapor
(gas)
Temperature (°C)
Pressure (atm)
1-
0.5-
0.25-
0
OA. Gas
OB. Liquid
O C. Solid
OD. Gas and liquid
10
Ice
(solid)
0.01
100

Answers

The phase of water at 0.5 atm and 100°C is gaseous phase.

What is water phase?

Water exists in three different phases such as liquid, gas, and solid.

The phase of the given water can be determined using phase diagram at standard temperature and pressure as shown in the image uploaded.

At 0.5 atm and 100 °C, the water is still in vapour or gaseous phase.

Thus, the phase of water at 0.5 atm and 100°C is gaseous phase.

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a)6.144
b)0.644
c)-0.644

Answers

Answer:

b

Explanation:

is the dictionary definition of a word.

is the feeling or idea associated with a word.

Do you like the eye color black or blue better?

Answers

Answer:

black.

Explanation:

I like seeing myslef, so therefore with black eyes I would be seeing my reflection

In terms of physical appearance, I would choose blue. However, I genuinely would prefer to have black colored eyes. My eyes in real life are brown though, and I’m content with what I have.

what information we get Chemical equation ?​

Answers

Answer:

We get the following information from a chemical equation :--

1. We get the symbol and formulas of the reactants and products.

2. The physical state of the reactants and products.

3. From this reaction, we can know the molecular formula of ammonia, water and nitrogen.

4. Here all the species are in a gaseous state.

5. The reaction takes place at a high temperature and pressure.

6. Zinc metal reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas. This equation is written as:

Zinc metal reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas. This equation is written as: Zn+H2SO 4→ZnSO 4 +H2.

What isotope has 45 protons and 57 neutrons

Answers

…Answer:

Explanation:

What is the maximum mass of ammonia that can be formed when 36.52 grams of nitrogen gas reacts with 10.62 grams of hydrogen gas according to the following equation? Please round your answer to the nearest 0.01 gram.

N2 + 3 H2 = 2 NH3

Answers

The maximum mass of NH₃ that can be formed when 36.52 g of N₂ reacts with 10.62 g of H₂ is 44.35 g

Balanced equation

N₂ + 3H₂ —> 2NH₃

Molar mass of N₂ = 14 × 2 = 28 g/mol

Mass of N₂ from the balanced equation = 1 × 28 = 28 g

Molar mass of H₂ = 2 × 1 = 2 g/mol

Mass of H₂ from the balanced equation = 3 × 2 = 6 g

Molar mass of NH₃ = 14 + (3×1) = 17 g/mol

Mass of NH₃ from the balanced equation = 2 × 17 = 34 g

SUMMARY

From the balanced equation above,

28 g of N₂ reacted with 6 g of H₂ to produce 34 g of NH₃

How to determine the limiting reactant

From the balanced equation above,

28 g of N₂ reacted with 6 g of H₂

Therefore,

36.52 g of N₂ will react with = (36.52 × 6) / 28 = 7.83 g of H₂

From the above calculation, we can see that only 7.83 g out of 10.62 g of H₂ are required to react completely with 36.52 g of N₂.

Therefore, N₂ is the limiting reactant

How to determine the maximum mass of NH₃ produced

From the balanced equation above,

28 g of N₂ reacted to produce 34 g of NH₃

Therefore,

36.52 g of N₂ will react to produce = (36.52 × 34) / 28 = 44.35 g of NH₃

Thus, the maximum mass of NH₃ obtained from the reaction is 44.35 g

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Compounds I and II can be distinguished by comparing the number of signals in their 1H NMR spectra. How many signals are expected in the 1H NMR spectrum of each compound

Answers

The spectrum of the first compound will have only one signal, but the spectrum of the second compound will have two signals.

What is a compound?

A compound is a substance formed by combining two or more different chemical elements in such a way that the atoms of the individual elements are linked together by chemical bonds that are difficult to break in chemistry.

Hence it is right to state that the spectrum of the first compound will have only one signal, but the spectrum of the second compound will have two signals.

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What do makeup experts use in order to create different skin effects?

Answers

Answer:

on-skin silicone, liquid latex, and gelatine

Explanation:

hope this helps:)

How many grams of CO₂ gas would occupy 33.7 L of volume at a temperature of
-22.2°C and a pressure of 990 mm Hg?
1.3atm

Answers

Let's see

moles of CO_2

PV=nRTn=PV/RTn=990(33.7)/(251.8)(8.314)n=15.9mol

Mass of CO_2

Molar mass×n15.9(44)699.6g
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