Chemistry questions below! (●'◡'●)
1. Islands in the middle of the oceans (for example, Great Britain, Hawaii, Bermuda) tend to have more stable climates with smaller temperature fluctuations than regions of the same mass surrounded by land (for example, continents). Use your knowledge of heat energy, specific heat, and heat transfer to explain these facts.
2. Baking soda is sodium bicarbonate (NaHCO3). When you heat baking soda, it breaks down into sodium carbonate powder (Na2CO3), water vapor, and carbon dioxide. The enthalpy of this reaction is 129 kJ. Write a correct thermochemical equation for this reaction, explain how you came up with this equation, and explain what it tells you about the reaction.
Answers
(1) Islands are always surrounded by bodies of water, in this case oceans. These islands tend to have more 'stable climates' and 'smaller temperature fluctuations' due to the specific heat of water, which is quite high, 4180 J/kg C. The higher the specific heat, the more the energy needed to raise the temperature of the substance. Land requires less energy to raise it's temperature than water due to it's lower specific heat. Thus, islands tend to have more stable temperatures than regions surrounded by land.
(2) Based on the conditions provided, the thermochemical equation for the reaction should be:
2NaHCO₃ (s) ---> Na₂CO₃ (s) + H₂O (g) + O₂ (g)
This is a decomposition reaction, as it explains that the baking soda breaks down into the products. All we had left to do is balance the equation, adding 2 as the coefficient of the reactant.
(3) Let's rewrite the given equations:
First chemical reaction: H₂(g) + F₂(g) ---> 2HF(g), ΔH₁ = –537 kJ.
Second chemical reaction: C(s) + 2F₂(g) ---> CF₄(g), ΔH₂ = –680 kJ
Third chemical reaction: 2C(s) + 2H₂(g) ---> C₂H₄(g), ΔH₃ = +52.3 kJ.
Fourth chemical reaction: C₂H₄(g) + 6F₂(g) ---> 2CF₄(g) + 4HF(g), ΔH₄ = ?
Now the 'fourth chemical reaction' is the one in which we need to determine the enthalpy:
ΔH₄ = 2(ΔH₁) + 2(ΔH₂) - ΔH₃,
ΔH₄ = 2(–537) + 2(–680) - 52.3 = -2486.3 kJ
Related Questions
2. Express 165,000 in exponential notation.
A) 1.65000 x 105
B) 1.65 x 10$
C) 1.6500 x 105
D) 1.65 x 105
E) 165 x 10
Answers
Answer:D
Explanation:
Move the decimal back 5 times.
3. Dorji was provided with four colourless solutions. He was asked to
identify the type of solution using universal indicator. Dorji's finding is
recorded in Table 8.5. Use the information from Table 8.5 to answer the
questions that follow.
Table 8.5.
Solution
COA
Colour change of universal indicator
Red
Blue
Purple
Yellow
en
i. What type of solutions are solution A and solution C?
ii. Which solutions do you think are:
a. acidic in nature?
b. basic in nature?
iii. What will happen if equal volume of solution B and solution D are
mixed?
Answers
Answer:
First, we can test Solution 1. We know that Sodium Hydroxide is a strong base. If we test acids on blue litmus paper, they will turn red. If we test bases on red litmus paper, they will turn blue. So, you can test all the of the solutions- water, sodium hydroxide and hydrochloric acid with blue and red litmus paper. HCl, Hydrochloric acid is an acid, so it will turn blue litmus paper red. It will not turn red litmus blue. The acids will turn blue litmus paper red. The bases will turn red litmus paper blue. Only water is a neutral liquid, which will not turn blue litmus paper red or red litmus paper blue. It will not change the colour of it. Thus, if you test all the solutions with blue and red litmus paper, you will know which solution is water. Water is the only one which is neutral. It is the only solution which cannot change the colour of any litmus paper. Thus, you can identify it very easily.
What are the number of protons, neutrons, and electrons in an atom of Tellurium- 129?
Answers
Answer:
Number of protons = 52, Number of electrons = 52, Number of neutrons = 76
Explanation:
What is the most dense a marble(2,56), quartz (2.64), or diamond (3.52).
Answers
Complete Question
What is the most dense a marble(2.56), quartz (2.64), or diamond (3.52).
Answer:
Diamond with a density of 3.52
Explanation:
When we say an object is dense, this means how heavy a substance or object can be.
Density can be defined as the mass per unit volume of an object of an object or a substance.
In the above question, we were given 3 substances or compounds with their respective densities:
marble(2.56)
quartz (2.64)
diamond (3.52).
We are asked to find the one that is most dense. This means we are to find the one with the highest density.
From amongst the three compounds, the most dense is Diamond with a density of 3.52.
help me please it's important
Answers
Q2. True
Hope this helps you ♥︎ *sips...* ahhh... ok I’m finished here
Can someone name an element that doesn’t match its abbreviation?
Answers
Answer:
Gold, silver and sodium.
Explanation:
Gold, silver and sodium are the name of the elements which does not match to their abbreviation. It is because those names are comes from other language. For example, the symbol of sodium is Na which comes from Natrium that is a Latin word. The symbol of gold is Au which comes from Aurum that is also a Latin word. The symbol of silver is Ag which comes from a Latin word i. e. Argentum.
Each of five students used the same ruler to measure the length of the same pencil. These data resulted: 15.33 cm, 15.34 cm, 15.33 cm, 15.33 cm, 15.34 cm. The actual length of the pencil was 15.85 cm. Describe whether accuracy and precision are each good or poor for these measurements.
Answers
Answer:
Precision is good but accuracy is poor
Explanation:
The precision in a measure is about how close is a measured value to each other. In the problem, all measurements are between 15.33 and 15.34cm. Thus, you can say precision is good
And accuracy is about how close are the measured values to the theoretical or real value. The real length of the pencil is 15.85cm. The measurements are not even close of the real value. For that reason, you can sat accuracy of the measurements is poor.
The precision was good while the accuracy was poor. Precision is defined
as how close measurements are with each other.
We were told the data from the measurement was between 15.33cm-
15.34cm which shows how close the measurements are hence having a
good precision.
The accuracy is defined as how close a measurement is to the theoretical
or actual value. In this case, the actual value is 15.85cm which is far from the
values gotten from measurements hence signifying the accuracy was poor.
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which physical property of the alkali metal group decreases down the group
Answers
Answer:
Melting and boiling point
Explanation:
For all group 1 elements, the melting and boiling point of the various members of the group decreases down the group. Hence, as the elements become heavier, they tend to have lower melting and boiling points.
Thus in moving from lithium to francium, there is a steady decrease in the melting and boiling points of elements down the group.
How are the atoms
or molecules
arranged in solid?
Answers
Answer:
Gases, liquids and solids are all made up of atoms, molecules, and/or ions, but the behaviors of these particles differ in the three phases. ... gas are well separated with no regular arrangement. liquid are close together with no regular arrangement. solid are tightly packed, usually in a regular pattern.
Hope this helped :)
Explain why the Bohr model was insufficient and how the quantum model explained this deficiency. How is the electron viewed differently in each model
Answers
Answer and Explanation:
Bohr's model of the atom defined the electron as a particle that orbits around the nucleus in only certain orbital levels. As a result, it couldn't readily give account of the energy levels of larger elements with high atomic number.
The quantum model of the atom however, approaches the electron in an atom as not just a particle but a wave, with its distinct quantum number per energy level. It can therefore give the position and speed of an electron simultaneously at any energy level.
I hope this explanation is sufficient.
What is The ratio of atoms in HCI is
Answers
Answer:
Each molecule of HCl is composed of a one-to-one ratio of hydrogen and chlorine.
Explanation:
At room temperature, HCl is a colorless, poisonous gas. Dissolve it in water, and, voilà, you have hydrochloric acid. For the record, acids are substances that release hydrogen ions in water. The more hydrogen ions an acid releases in water, the stronger the acid (see "What is an ion?" below). If you concluded from the above discussion that HCl releases many hydrogen ions in water, you are right!
The ratio of atoms in HCl is
1:1The ratio of atoms in hydrogen chloride shortened as HCl is 1:1. This is because there is only one atom of hydrogen that is reacted with another atom of chlorine. A ratio indicates the relative sizes of two or more quantities.
When given another compound like H₂ SO₄, we can describe the elements as being in the ratio of 2:1:4. Thus, we can see the relative quantities of the individual elements in the given compound.
In conclusion, the ratio of atoms in HCl is 1:1.
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Question 3 0
A student has a lg sample of each of the following compounds: NaCl, Br, and KCL. Which of the following lists the samples in order of increasing number of moles in the sample?
Answers
Answer:
Option D. KBr < KCl < NaCl
Explanation:
We'll begin by calculating the number of mole of each sample.
This can be obtained as follow:
For NaCl:
Mass = 1 g
Molar mass of NaCl = 23 + 35.5 = 58.5 g/mol
Mole of NaCl =?
Mole = mass /Molar mass
Mole of NaCl = 1/58.5
Mole of NaCl = 0.0171 mole
For Kbr:
Mass = 1 g
Molar mass of KBr = 39 + 80 = 119 g/mol
Mole of KBr =?
Mole = mass /Molar mass
Mole of KBr = 1/119
Mole of KBr = 0.0084 mole
For KCl:
Mass = 1 g
Molar mass of KCl = 39 + 35.5 = 74.5 g/mol
Mole of KCl =?
Mole = mass /Molar mass
Mole of KCl = 1/74.5
Mole of KCl = 0.0134 mole
Summary
Sample >>>>>>>> Number of mole
NaCl >>>>>>>>>> 0.0171
KBr >>>>>>>>>>> 0.0084
KCl >>>>>>>>>>> 0.0134
Arranging the number of mole of the sampl in increasing order, we have:
KBr < KCl < NaCl
There are 4.288 x 10^24 particles of sand in a bucket you
have from the beach. How many moles of sand do you
have?
Answers
Answer:
7.12 moles of sand you have in the bucket
Explanation:
Moles are defined as a determined amount of particles. To relate moles with particles it is used Avogadro's number (6.022x10²³ particles / mole).
That means in 1 mole of a determined particle you will have 6.022x10²³ particles.
As in the bucket there are 4.288x10²⁴ particles:
4.288x10²⁴ particles * (1mole / 6.022x10²³ particles) =
7.12 moles of sand you have in the bucketWhat do you think the scientific question is for the
boiling water experiment
Answers
Answer:
Scientific Question: ... I will boil water and add a substance like salt to see if the boiling point increases.
An airplane travels 2100 km at 1000km/hE. It encounters a wind and slows to 800 km/h E for the next 1300 km. What is the average velocity of the airplane for this trip?
Answers
Answer:
The average velocity of the airplane for this trip is 1684.21 km/h
Explanation:
Average velocity is the rate of change of displacement with time. That is,
Average velocity = [tex]\frac{Displacement }{Change in time}[/tex] = Δx / Δt = [tex]\frac{x2 - x1}{t2 - t1}[/tex]
Now we will calculate the time taken by the airplane for the first motion before it encounters a wind.
From,
Velocity = [tex]\frac{Distance traveled}{Time taken}[/tex]
Time = [tex]\frac{Distance traveled}{Velocity}[/tex]
Therefore, Time = [tex]\frac{2100km }{1000km/h}[/tex]
Time = 2.1h
This is the time taken before the airplane encounters a wind.
Hence, t1 = 2.1h
Now, For the time taken by the airplane when it encounters a wind
Also from,
Velocity = [tex]\frac{Distance traveled}{Time taken}[/tex]
Time = [tex]\frac{Distance traveled}{Velocity}[/tex]
Therefore, Time = [tex]\frac{1300km }{800km/h}[/tex]
Time = 1.625h
Hence, t2 = 1.625h
Now, to calculate the average velocity
Average velocity = [tex]\frac{x2 - x1}{t2 - t1}[/tex]
x1= 2100, x2= 1300, t1= 2.1h and t2= 1.625h
Hence, Average velocity = [tex]\frac{1300 - 2100}{1.625 - 2.1}[/tex]
Average velocity = 1684.21 km/h
calculate and compare the chemical energy of coal to its gravitational potential energy. Burning 1 kg of coal releases about 3 million joules of energy. if you could use all of the chemical energy to lift another kilogram of coal, how could you lift it?
Answers
Answer:
Explanation:
1 kg of coal releases 3 million joules of energy
energy released = 3 x 10⁶ Joules
This energy will be in the form of chemical energy .
This energy is being used ti lift 1 kg of coal . Let height attained be h .
Gravitational potential energy of coal at height h = mgh where m is mass of the coal , g is gravitational acceleration .
chemical energy = gravitational energy
mgh = 3 x 10⁶
1 x 10 x h = 3 x 10⁶
h = 3 x 10⁵ m
= 300 x 10³ m
= 300 km .
so , 1 kg coal can be lifted by 300 km .
1. Justin usually blows his nose using Kleenex tissues. His snot keeps leaking through the tissue. He decided he is going to create an experiment to find out if there is something better. What is his dependent variable?
Answers
Answer:
His snot.
Explanation:
Because a dependent variable is a variable (often denoted by y ) whose value depends on that of another, and a example is test scores, those are a dependent variable. And it's his snot because his snot keeps leaking and hes going to create an experiment to see if he can solve it.
The dependent variable of Justin's experiment is the mass of the snot the tissue can hold.
What are variables?A variable can be described as an alphabet that can be used to represent an unknown number. Variable generally represents the value. A variable can be described as a quantity that can be changed according to the given mathematical problem.
The dependent variable can be defined as a variable that will depend on the value of some other number. The dependent variable is also defined as the output of a function. If the value of the dependent variable will change therefore there is a change in the value of the respective independent variable.
The independent variable of the experiment will not depend on the values of other variables and is known as the input of a function. The value of the independent variable will not affect by any values of a variable.
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Please answer!! I’ll make brainliest!!
Answers
Answer:
greater than 115 N upwards
Explanation:
Convert 1750042 to scientific notation.
Answers
Explanation:
Answer is above.. 1.750042* 10 race to 6
A chemist adds two substances together in a beaker. When he combines the substances, a solid substance is formed. He filters the solid substance and measures its mass on an electronic balance. When the chemist measures the mass of the substance, he is A. collecting relevant data. B. devising a hypothesis. C. making a prediction. D. drawing a conclusion.
Answers
Answer:
collecting relevant data
Explanation:
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if 1/4 cups are in 1 serving jow many servings are in 4 cups
Answers
Answer:
One serving is 1/4 cup therefore 1 cup would be 4 servings. Since we have 9 cups we would then multiply 9 x 4 and the answer would be 36 servings. You have a ratio of cups to serving, so 1/4 cup : 1 serving, or .
Explanation:
The atmospheric pressure on a mountain is 550 mmHg and 1
atm is equal to 760 mmHg. What is the pressure in atm? Give
your answer to 2 significant figures.
Answers
Answer:
0.72
Explanation:
if 760=1
550=x
=550÷760= 0.72 in two s.f
The atmospheric pressure of the mountain will be 0.723 atm
What is atmospheric pressure?
Air is everywhere around us at due to which it touches all the surfaces due to which they possess some pressure this exerted pressure is known as atmospheric pressure which can be calculated with this formula.
1 atm = 760 mmHg
1 mmHg = 0.00131 atmosphere
Substituting the value of 1 atm in the given equation,
1mmHg = 0.00131 atmosphere
550 mmHg = 0.00131
= 550 × 0.00131
= 0.723 A T M
It is the total force exerted by the atmosphere as AIR has small molecules and every molecule is possessing some weight as when they are in bulk they form layers these layers.
As we go above on the earth the atmospheric pressure will drops due to the increase in the altitude of the earth due to which there will be less amount of oxygen.
Therefore, the pressure will be 0.723 atm.
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In 25 words or fewer, what is the scientific question for the boiling
water experiment?
Answers
Answer: Does adding salt to water make the water boil faster that if salt is not added?
Explanation:
The scientific question for the boiling water experiment could be: "What is the effect of increasing temperature on the boiling point of water?"
This question aims to investigate how temperature influences the boiling point of water. By conducting the experiment and analyzing the results, scientists can gain a better understanding of the relationship between temperature and the physical state change of water from liquid to vapor.
The question focuses on a specific variable (temperature) and its impact on the boiling process, allowing for a targeted investigation and potential insights into the behavior of water under different conditions.
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While doing a lab a student found the density of a piece of pure aluminum to be 2.85 g/cm3 the accepted value for the density of aluminum is 2.70 g/cm3. What was the percent error
Answers
Answer:
THE PERCENT ERROR IS 5.55 %
Explanation:
To calculate the percent error, we use the formula:
Percent error = Found value - accepted value / accepted value * 100
Found value = 2.85 g/cm3
Accepted value = 2.70 g/cm3
Solving for the percent error, we have:
Percent error = 2.85 g/cm3 - 2.70 g/cm3 / 2.70 g/cm3 * 100
Percent error = 0.15 / 2.70 * 100
Percent error = 0.05555 * 100
Percent error = 5.55 %
In conclusion, the percent error is 5.55 %
At 27 C
and one atmospheric pressure, a gas has volume V. what will be its volume at 177 C
and a pressure of
1.5 atmosphere?
Answers
Explanation:
According to Charles Law :
[tex] \frac{V_1}{T_1} = \frac{V_2}{T_2} [/tex]
[tex] \frac{V}{27} = \frac{1.5}{177} [/tex]
[tex]V = 0.22 \: atm[/tex]
Which of the following is closest in meaning to the word “hypothesis”?
Fact
Law Formula
Suggested explanation
Conclusion
Answers
Answer:
suggested explanation
Explanation:
a hypothesis is like a guess to a question. then you test the guess.
The closest meaning of the word “hypothesis” is the suggested explanation. The correct option is C.
What is a hypothesis?
A hypothesis is a theory that is made by seeing a thing and explaining a description of that thing. A hypothesis must be testable according to the scientific method for it to be considered a scientific hypothesis.
Scientific hypotheses are typically based on prior observations that cannot be adequately explained by the current body of knowledge. To make a hypothesis, there is a proper observation.
The proposed explanation is a good example of a hypothesis. Because before making a hypothesis, there is a submitted explanation that will be used in proving the test.
Thus, the correct option is C. Suggested explanation regarding hypothesis.
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What effect did the new study have on scientists' ideas about the way Earth's water formed? (A) Scientists are convinced that Earth mostly got the hydrogen for its water from other nearby planets that have water. (B) Scientists believe the solar nebula may have provided an extra source of hydrogen that helped water form on Earth. (C) Scientists are questioning whether asteroids even hit the Earth and helped it form the water on it. (D) Scientists are concerned that they will never learn the true cause behind the formation of water on Earth.
Answers
Answer: (C) Scientists are questioning whether asteroids even hit the Earth and helped it form the water on it.
Explanation:
The scientists are collecting evidence for the fact that the earth's water is the product of the gas left due to the formation of the sun and the asteroidal material. The fact finding inquiry related to this matter has also arose many questions related to the development of the other planets on the solar system and their potential to sustain or support life.
Hence, based on the above information, option C. is correct.
Help please 20points
Answers
Answer:
D
Explanation:
D is the answer because this is the only one having to do with genetics. Fox's genetics changed because it's environment changed.
What comes right before the "analyzing the data" step of the scientific
method?
O A. Predicting a theory
O B. Testing the hypothesis
O C. Conducting an experiment
O D. Collecting the data
I need someone to answer this quickly please!!
Answers
Answer: d collect the data
Explanation:
Collecting the data and making observations comes right before the "analyzing the data" step of the scientific method. Therefore, option (D) is correct.
What is a scientific theory?The scientific method can be described as an empirical method for acquiring knowledge that has developed in science since at least the 17th century.
The scientific theory includes careful observation, applying what is observed, given that assumptions can distort how one interprets the observation. . A scientific hypothesis is possible to identify a possible outcome of an experiment that conflicts with predictions deduced from the hypothesis.
The scientific theory involves hypotheses, through induction, based on such observations, the testability of hypotheses, experimental and measurement-based statistical, and elimination of the hypotheses based on the experimental findings.
The process in the scientific method includes making hypothetical explanations, and predictions from the hypotheses as logical consequences and then conducting experiments or empirical observations based on those predictions.
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Explain that the giant ionic lattices are held together by the attraction between oppositely charged ions.
Answers
Answer:
hope it helps!!!!!!!!!!!!!!!!!!!!!
Explanation:
An ionic compound is made up of charged particles, called ions. It has a giant lattice structure with strong electrostatic forces of attraction.
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