Answer:
If the reaction loses heat it is exothermic.
Two chemical reactions are shown:
A. Ca(OH)2 - CaO + H2O
B. 4K + O2 + 2K20
Which statement is true?
A. Both are synthesis reactions
B. Both are decomposition reactions
C. A is a synthesis reaction, and B is a decomposition reaction
D. A is a decomposition reaction, and B is a synthesis reaction
Answer: A is a decomposition reaction, and B is a synthesis reaction
Explanation: the first equation shows the reactant breaking up into 2 parts aka decomposition and equation 2 shows the reaction being combined into one part, aka synthesis. hope that helps!
Answer:
Answer d
Explanation:
Please help! Giving 20 points!
Question: How can NASA scientists use Newton's third law of motion to plan for a space vehicle landing on a meteor? Make a claim. Support your claim with evidence from the article. Then, explain why the evidence supports your claim.
Article: https://newsela.com/read/lib-newton-third-law/id/54749/
Answer:
Explanation:
NASA uses rockets to launch astronauts and supplies to the International Space Station. Launching a rocket relies on Newton's Third Law of Motion. A rocket engine produces thrust through action and reaction. The engine produces hot exhaust gases which flow out of the back of the engine
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1
a
C
Copper(II) nitrate decomposes on heating. The reaction is endothermic.
2Cu(NO),(s) → 2CuO(s) + 4NO2(g) + 0,(9)
Sketch a reaction pathway diagram for this reaction to include the
activation energy
[3]
b Draw an energy cycle to calculate the standard enthalpy change for
this reaction, using enthalpy changes of formation.
[3]
Calculate the enthalpy change for this reaction using the following
enthalpy changes of formation.
AH, [Cu(NO, ),(s)] = -302.9 kJ mol-'
AH, [CuO(s)] =-157.3 kJ mol-!
AH [NO,(g)] = +33.2 kJ mol-!
[3]
d Copper(II) sulfate is soluble in water. A student dissolved 25.0 g of
copper(II) sulfate in 100 cm of water in a polystyrene beaker stirring
all the time. The temperature of the water fell by 2.9 °C.
i Calculate the enthalpy change of solution of copper(II) sulfate.
(specific heat capacity of water = 4.18 Jg1 °C ; relative
molecular mass of copper(II) sulfate = 249.7 g mol-')
[3]
ii Suggest one source of error in this experiment and explain how
the error affects the results.
[2]
[Total: 14]
This problem provides information about the decomposition of copper(II) nitrate to copper(II) oxide and dinitrogen monoxide; for example, it is endothermic, the enthalpies of formation and the chemical reaction, as well as copper (II) sulfate which when dissolved in water, exhibits a temperature decrease:
[tex]2Cu(NO_3)_2(s) \rightarrow 2CuO(s) + 4NO_2(g) + O_2(g)[/tex]
First of all, we can draw the reaction pathway as shown on the attached figure, by taking into account the positive enthalpy change as it is endothermic, so that the products turn out with higher energy than the reactants, for it to be positive. In addition, keep in mind that top point is the activation energy the reaction needs to take place.
Next, we calculate the enthalpy change for this reaction by using the general formula which subtracts the enthalpy of formation of products and reactants with each species' correct stoichiometric coefficient:
[tex]\Delta H=2\Delta _fH_{CuO}+4\Delta _fH_{NO_2}+\Delta _fH_{O_2}-2\Delta _fH_{Cu(NO_3)_2}[/tex]
So we plug in the given enthalpies of formation:
[tex]\Delta H=2(-157.3)+4(33.2)+(0)-2(-302.9)=424.0 kJ/mol[/tex]
Finally, we go over the calorimetry experiment, whereby the total heat absorbed by the copper(II) sulfate is calculated via the general heat equation, which includes the heat loss from the solution of water and the salt:
[tex]Q_{rxn}=-mC_w\Delta T\\\\Q_{rxn}=-(100+25)g*4.18\frac{J}{g\°C}*-2.9\°C=1515.25J[/tex]
By dividing the previous answer by the moles of salt:
[tex]n=25.0g*\frac{1mol}{249.7g}=0.100mol[/tex]
We can obtain the enthalpy change of solution of the copper salt:
[tex]\Delta _{dissolution}H=\frac{1,515.25J}{0.100mol} \\\\\Delta _{dissolution}H=15,134J/mol=15.1kJ/mol[/tex]
To conclude, it is important to note that one possible source of error is we are assuming the solution has the same specific heat to that of water and that is not necessarily true. Also, we are neglecting any heat transfer to and from the surroundings despite the polystyrene beaker is considered a heat isolator, which means the results cannot necesarilly be accurate and the enthalpy change could have turned out higher or lower in a rigoruous experiment.
Learn more:
https://brainly.com/question/15862043https://brainly.com/question/11667877Will the things dissolve by themselves over time?
When a substance dissolves, it looks like it disappears. But in fact it has just mixed with the water to make a transparent (see-through) liquid called a solution. A solution has two parts. The solute is the solid that gets dissolved.
Answer:
it really depends what they are
Explanation:
Describe the physical properties of Copper (Cu) based on what you know about metals, nonmetals, and metalloids
Answer:
Copper is reddish brown color
Its density is 8.93 g cm-3
highly malleable at ordinary temp, but is brittle near its melting point
god conductor of heat and electricity
Explanation:
What is carbon? What does it do?
What is the wave length of an electromagnetic radiation ,having a frequency of 5.2 x 10^12 Hz? Note: c= 3.00 x 10^8 m/s
Answer:
[tex] \huge{5.77 \times {10}^{ - 5} m}[/tex]
Explanation:
The wavelength of a wave can be found by using the formula
[tex]\lambda = \frac{c}{f} \\[/tex]
where
c is the speed of the wave
f is the frequency
From the question we have
[tex] \lambda = \frac{3 \times {10}^{8} }{5.2 \times {10}^{ 12} } \\ \\ \\ \\ \large{ = 5.77 \times {10}^{ - 5} m}[/tex]
Hope this helps you
What is the meaning of term Amino acid
Answer:
Amino acids are molecules that combine to form proteins.
Explanation:
Amino acids are molecules that combine to form proteins. Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids to make proteins to help the body: ... Repair body tissue.
Hope this helps :)
Write the balanced chemical equation for the reaction
of solid carbon with oxygen gas to form carbon monoxide gas.
Answer:
2C +O2 - COExplanation:
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The balanced chemical equation for the reaction of solid carbon with oxygen gas to form carbon monoxide gas is 2 C + O₂[tex]\rightarrow[/tex] 2 CO.
What is chemical equation?Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.
A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .
The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.
Learn more about chemical equation,here:
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How to calculate work done with change in volume and pressure.
[tex]W = \displaystyle \int dW = \displaystyle \int^{V_2}_{V_1} p ~dV = p(V_2 - V_1) = p \Delta V[/tex]
una pieza de hierro de 25cm3 tiene una masa de 195g cual es su densidad?
Answer:
Pretend you are a TV producer. Think of ideas for new TV shows. Your objective is to create ideas that will be successful, regardless of whether this is quality programming or not. Think of an idea of a copy. Explain the basics of what this show will be like and what show it is copying. Explain why you feel this show will be popular. Think of an idea of a spin-off. Explain the basics of what this show will be like and what show it is spinning off from. Explain why you feel this show will be popular. Think of an idea for a TV show that falls into one of the genre categories listed in the genre chart. Describe the basics of the show and how it falls under the genre’s expectations for characters, plots, and aesthetics. Explain why you feel this show will be popular.
Distinguish between the first, second, and third ionization energies of an atom. b. How do the values of successive ionization energies compare
Answer:
The third ionization energy is the energy it takes to remove an electron from a 2+ ion. (That means that the atom has already lost two electrons, you are now removing the third.) And 2nd ionization energy is higher than 1st ionization energy, 3rd is higher than 2nd, and so forth.
hope it is helpful :)
Does chlorine have a smaller ionic radius than soium.
Answer:
sodium atoms are much larger than chlorine atoms but in case of sodium ions they are much smaller thqn chlorine ions
2. How many of valence electrons do the elements in column 4 have? Are these elements very reactive?
Explain your answer.
Answer:
4
Explanation:
Elements in group 14 have 4 valence electrons. Meaning that to achieve a stable octet they need to either gain or lose 4 electrons in total.
what is the difference in chemical energy between organic and inorganic materials?
Answer:
the difference is the presence of a carbon atom
Explanation:
Please help me no links
if good answer you get brainliest
Answer:
plutonic rocks are formed when magma cools and solidifies underground This shows us if the rock is plutonic or volcanic. When magma cools underground, it cools super slow and when lava cools above ground, it cools faster. When magma and lava cool, mineral crystals start to form in the molten rock.
Explanation:
i hope this is correct
what word describes when tiny droplets of one liquid are finely dispersed within another liquid?
When tiny droplets of one liquid are finely dispersed within another liquid it is called emulsion.
Emulsion can be defined as the process by which two liquids that are not miscible come together to form a mixture.
The emulsion mixture usually consists of an oil phase and a water phase.
The oil phase appears as droplets when dispersed (mixed with) the water phase.
The uses of emulsion include:
It is used in chemical industries for production.It is used for production of medicine.Digestion of fatty food components in the intestine takes place through the process of emulsion.Learn more here:
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What is the agent that causes frost wedging?
Answer:
Freeze wedging is caused by the repeated freeze-thaw. Frost wedging occurs as the result of 9% expansion of water when it is converted to ice. Cracks filled with water are forced further apart when it freezes.
HURRY for a BRAINLIST
Answer:
B
Explanation:
Answer:
answers
B
Explanation:
Explicaciónexplicacaca
Complete the sentence.
Atoms form chemical bonds to satisfy the ______
rule and to become _______
Explain how magnesium is produced at the negative electrode from molten magnesium chloride
Answer:
being cation it migerates to cathode to be reduced to elemental magnesium
Explanation:
Mg+2. +2e -----------Mg
For accurate answer i will mark you a brainlist:D
How will you convert 85 cm to 85 m, choose one of the following option:
( Remember there is a decimal in 85 after 5)
Question 12 options:
Move the decimal in 85 TWO places to the right to decrease the value.
Move the decimal in 85 THREE places to the right to increase the value.
Move the decimal in 85 TWO places to the Left to decrease the value.
Move the decimal in 85 THREE places to the Left to decrease the value.
Answer:
welp it would be this option : Move the decimal in 85 TWO places to the right to decrease the value.
Explanation:
Answer:
Option A
Explanation:
Moving the decimal point 2 places to the right will give you 8500 cm=85m
Compared to the energy of an electron in the second shell of an atom of sulfur, the energy of an electron in the
1
first shell is lower
2
first shell is the same.
3
third shell is lower
4
third shell is the same.
Answer:
First shell is lower
Explanation:
The electron has to absorb energy to excite and go to higher energy levels/ shells and should release energy to go to lower energy levels/ shells. This means higher the shell , more energy is required and vice versa
14 In which group are all the elements found
naturally only in compounds?
(1). 18
(3) 11
(2) 2
(4) 14
an atom of ordinary hydrogen consists of an electron and a
Answer: hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral atom contains a single positively charged proton and a single negatively charged electron bound to the nucleus by the Coulomb force.
Explanation:
An atom of ordinary hydrogen consists of one electron and one proton and zero neutrons.
What is a hydrogen atom?Hydrogen is a chemical element placed at the top of group 1 in the periodic table and is represented by the chemical symbol H and atomic number 1.
A hydrogen atom is the lightest atom of the element in the whole periodic table. Hydrogen exists as a gas of diatomic molecules having the formula H₂ at standard conditions. Hydrogen gas is tasteless, colorless, odorless, non-toxic, and highly combustible.
Hydrogen is constituting roughly 75% of all normal matter and is the most abundant chemical substance in the universe. Most of the hydrogen element on Earth exists in forms like water and organic compounds. Each atom of hydrogen (¹H) has one proton, one electron, and no neutrons.
Hydrogen element is nonmetallic and easily forms a single covalent bond with most nonmetallic elements, forming compounds like water.
Learn more about hydrogen, here:
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1. Which of the following statements pertaining to the ionic solids represented below are true?
(0)
1.
Both structure are ductile.
II. Structure (1) has a higher melting point than structure (ii)
III. Both structures conduct electricity in the solid state.
IV. Both structures conduct electricity in the liquid state.
Answer:
B
Explanation:
so A is nosense C and D the question is saying the stament for a being repersentation of solid not whether eletric or not
What is the formula for the ionic compound formed by calcium and selenium?
Answer:
CaSe
Explanation:
not sure!!
The half-life of Palladium-100 is 4 days. After 16 days a sample of Palladium-100 has been reduced to a mass of 6 mg. What was the initial mass (in mg) of the sample
Answer:
96mg
Explanation:
Since the half-life of Palladium-100 is 4 days and the sample has been reduced after 16 days, that means the sample has undergone four half-lives. To find the intial mass, just work backwards:
6 x 2= 1212 x 2= 2424 x 2= 48 48 x 2= 96As you see, I've worked backwards from the four half-lives. So the initial mass after 16 days is 96 mg.
What is q in chemistry.
Answer:
The reaction quotient!
Explanation:
hope this helped :D
Calculate the molecular mass of the element
They give:H=1,AI=27,S=32,0=16,Cu=64,P=31,Mg=24,N=14,Na=23
Answer:
Mg (NO3)2
24 + 2×(14+ 3×16)
24+2×(14+48)
24+2×(62)
24+ 124
=148g
