The best explanation for why a firework being ignited is an example of an exothermic reaction and not an endothermic reaction is:
The fireworks give off heat.
Heat is emitted into the environment in an exothermic reaction. When a firework is lit, it undergoes a number of chemical processes inside the firework combination, which produces gases and produces a great deal of heat. Fireworks' distinctive visual display and audible effects are produced when heat is released as light and sound.
In contrast, heat is taken from the environment during an endothermic reaction. If a reaction were endothermic, it would need an outside energy source to continue, and because it would be absorbing heat from its environment, it would feel chilly to the touch.
However, because they release heat and energy and brighten the night sky, fireworks are instances of exothermic reactions.
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What does the author predict about the future of the Earth's mantle? Do you support his educated guess? Use complete sentences to answer.
The earth's mantle will not change in the future because this region is safe from the intervention of human beings.
What happens in the Earth's mantle?The transfer of heat and material in the mantle helps us to determine the landscape of Earth. Activity in the mantle moves the plate tectonics, that contributes to volcanoes, seafloor spreading, earthquakes, and building of mountains.
So we can conclude that the earth's mantle will not change in the future because this region is safe from the intervention of human beings.
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A cup of hot water loses 265 cal
of energy to its surroundings.
How many joules of energy is
this?
[?] joules
Answer:
-1071 Joules
Explanation:
The Joule was introduced as the SI unit for energy in 1925. One calorie is equal to approximately 4.184 joules(J). This is a conversion factor that we can write two ways:
(1cal/4.184J) or (4.184J/1cal)
(265 cal)*(4.184J/1cal) = 1071 J
Since the energy is leaving the system, it should be written with a minus sign: -1071J
Answer:
1,108.76 joules
Explanation:
There are 4.184 joules per calorie
4.184 x 265 = 1,108.76
On a heating curve, in which section(s) would you use the equation, Q=mCΔT, to calculate the total heat required?
only on plateaus or flat parts of the curve
on a sloped part only if under 0oC
on a sloped part only if over 100oC
on all sloped parts of the curve
Answer:
all sloped parts
Explanation:
Sloped part of the curve - all as this would show a change in T ( or delta T)
the flat parts would involve no change in Temp
which are not oxidative reaction?
(look at the image)
Answer:
Cu²+ e ----> Cu+This is not oxidation as it gain electron .
Oxidation reaction means addition of oxygen or removal of hydrogen
or in other words loss of electrons
Mg ----> Mg²+ + 2e
this is oxidation reaction as Mg loss 2e to become +2
Sn³+ -----> Sn4+ + 2e
this is oxidation reaction as it losses electrons
similarly other are also oxidation.
3
Which statement describes the law of conservation of energy?
O All systems will exchange matter and energy with their surroundings.
O All systems can exchange energy, but not matter, with their surroundings.
Energy cannot be created nor destroyed, but it changes from one form to another.
O Energy is destroyed in most chemical reactions when new products are formed.
Energy cannot be created nor destroyed, but it changes from one form to another. Hence, option C is correct.
What is energy?Energy is the ability to do work.
In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time.
This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.
Hence, option C is correct.
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What type of molecule is shown below
Answer:
alcohol
Explanation:
alcohol thus, C2H5OH
plssssssssssssssssssssss helppppppppppppppppppppppppppppppppppppp
Answer:
protons and neutrons have different charges but they have approximately the same mass
First twenty element with electronic configuration
Citric acid (C6H8O7) is an important intermediate in the Krebs cycle and a triprotic acid. What is the normality of a solution made by weighing 128 g of citric acid into a volumetric flask and diluting it to 2 L with water
Answer:
2.67 N
Explanation:
The normality equation looks like this:
Normality = Molarity (M) x Number of Equivalents
In this formula, the number of equivalents represents how many moles of the acidic species exist in the molecule. In other words, how many hydrogen atoms are in citric acid? This value would be 8 equivalents (as denoted by the subscript).
So, to find the normality, you need to (1) convert grams C₆H₈O₇ to moles (via molar mass), then (2) calculate the molarity (via molarity equation using moles and volume), and then (3) calculate normality (via normality equation using molarity and # of eq.).
(Step 1)
Molar Mass (C₆H₈O₇): 6(12.011 g/mol) + 8(1.008 g/mol) + 7 (15.998 g/mol)
Molar Mass (C₆H₈O₇): 192.116 g/mol
128 g C₆H₈O₇ 1 mole
---------------------- x ---------------------- = 0.666 moles C₆H₈O₇
192.116 g
(Step 2)
Molarity = moles / volume (L)
Molarity = 0.666 moles C₆H₈O₇ / 2 L H₂O
Molarity = 0.333 M
(Step 3)
C₆H₈O₇ -----> 8 hydrogen atoms
Normality = molarity x number of equivalents
Normality = 0.333 M x 8
Normality = 2.67 N
Discuss how varying ph of water affects the soil ph which in turn would affect the durability properties of reinforced concrete as a constituent material?
Although soils are capable of resisting pH changes, there are some circumstances where the pH of the water can result in alterations.
Will Soil pH Be Affected by Water pH?The texture of soil affects how susceptible it is to the pH of the surrounding water. Smaller soil particles, such as clays and clay loams, have a greater impact than larger, sandier soils. There are more colloids, which are extremely minute particles, in fine-textured soils. Positively charged ions are maintained at these colloids. The cation exchange capacity of a soil refers to its capacity to hold onto these ions. Ions on the colloidal particles trade places with ions in the soil solution. The pH of the soil is less affected by negative ions in the soil solution.
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Solid aluminum and oxygen gas react to form solid aluminum oxide. Suppose you have 3.0 mol of Al and 11.0 mol of O2 in a reactor. Suppose as much as possible of the reacts. How much will be left? Round your answer to the nearest 0.1 mol.
8.75 moles of oxygen will be left
The reaction is
Al(s) + O₂(g) -----> Al₂O₃(s)
On balancing the equation, we get:
4Al(s) + 3O₂(g) -----> 2Al₂O₃(s)
If 3 mol of Al reacts, we need 3/4 x 3 = 9/4 = 2.25 mol of oxygenIf 11 mol of oxygen reactions, we need 11/3 x 4 = 44/3 = 14.7 mol of AluminiumBut we only have 3 mol of AlAluminium is the limiting reagent and all 3 moles of Al will reactWe get 2 moles of aluminium oxide from 4 moles of aluminium. So from 3 moles of aluminium, we get:3/4 x 2 = 6/4 = 1.5 moles of aluminium oxide
If we use 4 moles of Al, we need 3 moles of oxygenSo when we use 3 moles of Al, we need3/4 x 3 = 9/4 = 2.25 mol of oxygen
We had 11 moles of oxygenThe amount of oxygen left = 11-2.25 = 8.75 mol8.75 moles of oxygen will be left
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According to the concept of entropy, what will likely happen to most molecules over time?.
They're going to fall apart.
What most molecules will likely experience over time?A system's entropy cannot decrease unless heat is being lost from it. This indicates that entropy cannot decrease in a closed system (i.e., nothing enters or leaves, and that means nothing at all), so it must either remain constant or rise. Entropy can decrease, rise, or stay constant in an open system when movement between the system and its surroundings is conceivable. Both of these outcomes leave open the option of a constant state.
Entropy:-
The quantity of atom-alignment combinations that can exist in a system is known as entropy. The quantity of energy that cannot be used for work can also be calculated from an object's entropy.
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two different substance can have the same properties
Yes, you're absolutely correct
Atoms and the chemical bonds that connect them cannot be observed with your eyes, so it is necessary to use a
a. microscope
b. theory
c. model
d. both (b) and (c)
Answer: d. both (b) and (c)
Explanation:
Atoms are too small to be seen on microscopes, so we model them based on theories.
Discuss the importance of chemical reaction in our daily life?
Answer:
By observing chemical reactions, we are able to understand and explain how the natural world works. Chemical reactions turn food into fuel for your body, make fireworks explode, cause food to change when it is cooked, make soap remove grime, and much more.
hope it helps you
20) Mg + O2 → MgO
Reaction Type
synthesis (s)
decomposition (D)
single replacement (SR)
double replacement (DR) or combustion (C)
The given reaction Mg + O₂ → MgO is a type of Synthesis reaction. Hence option (1) is correct.
What is Synthesis reaction ?Synthesis reactions are reactions that occur when two different atoms or molecules interact to form one molecule or compound.
It is also known as combination reaction
In the given reaction Mg and O combines with each other to form one product i.e, MgO. Hence, The given reaction Mg + O₂ → MgO is a type of Synthesis reaction. Thus, option (1) is correct.
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Chemical bonds are formed when valence electrons are:
Chemical bonds are formed when valence electrons are shared or donated.
Chemical bondsChemical bonds are formed between two or more atoms when electrons are transferred or shared between or among the participating atoms.
For example, ionic bonds are formed when a metal ion such as Na donates its valence electrons to a non-metallic ion such as Cl to form NaCl.
Covalent bonds are formed when participating ions shared their valence electrons to give each other octet states.
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The table describes solids and plasmas.
-
Which statement can be placed in the blank cell to make the information in the table accurate?
can be crystalline
can be amorphous
are made of charged particles
are made of neutral particles
The statement that can be placed in the blank cell to make the information in the table accurate is Plasma : (D). are made of neutral particles
Meaning of plasmaPlasma can be defined as a form of matter, though its not as common as the three major forms of matter.
Plasma displays more of the features of a gas but it is not a gas. it has more density than a gas and is less dense than liquid and solid
In conclusion, The statement that can be placed in the blank cell to make the information in the table accurate is Plasma : (D). are made of neutral particles
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Answer:
Answer is (D) or fourth option
Explanation:
Plasmas are made of neutral particles
what must happen for carbon dioxide to sublimate at a given pressure?
a. energy must transfer from the carbon dioxide to its surroundings.
b. the average kinetic energy of the carbon dioxide molecules must
decrease.
o c. the orderliness of the carbon dioxide molecules must increase.
d. energy must transfer to the carbon dioxide from its surroundings.
Answer: d. energy must transfer to the carbon dioxide from its surroundings.
Explanation:
Sublimation is the phase change from a solid to a gas, meaning that the particles will have more kinetic energy (since particles in the solid phase are more ordered than particles in the gas phase, and thus particles in the gas phase have more energy). Thus, for sublimation to occur, the particles need more energy, which must come from its surroundings.
what could cause an error DNA in replication
NOTICE: There are attachments attached to this answer that is mentioned in each paragraph!
We frequently see DNA replication as a well-organized, methodical process, much like a production line. It's not. For the DNA polymerase to read it, the DNA must not lie in a straight line and must be in motion, not static. It is curled and twisted. First, realize that this is a molecular issue. Bacteria lack neurons, cannot "think," and cannot make decisions. Everything is a chemical reaction, and chemical reactions frequently depend on one concentration's osmotic pressure being higher than another, both inside the cell and outside. Even at that level, there is a lot of "nothing," albeit nothing is empty. For a better understanding of the environment, picture a cell as a large room filled with balls of all sizes. Each ball has a unique form and isn't spherical; some balls fit together flawlessly while others don't. This is the easiest way to conceptualize the universe of molecular chemistry. There is never "nothing" other than in space when you push your way through layers upon layers of free oxygen, free nitrogen, helium, carbon dioxide, hydrogen dioxide, argon, methane, etc. when you walk through what we term "air."
Replication mistakes happen. Sometimes DNA polymerase enzymes add the incorrect nucleotide, too many, or too few nucleotides to a sequence. Or the DNA polymerase gets looped on the same strand, adding a few codons in a repetition before the strand slips away and it continues, or there is a tangle of crossing DNA and it jumps to the incorrect thread and back (or never), etc. In order to ensure that the bases added to a developing strand are appropriately matched with their complements, DNA polymerase enzymes are quite picky about the nucleotides they choose to use. However, these enzymes do make errors. Specifically, at a rate of around 1 per 100,000 nucleotides. Doesn't sound like much, but since each diploid cell has 6 billion base pairs, there are around 120,000 errors every cell division.
Ribosomal errors during transcription can even change the synthesis of the DNA polymerase proteins, leading to the creation of a mechanism that is already faulty. Since not all ribosomes are created equally, ribosome quality is important. Bacterial mutation rates are greater because bacterial ribosomes are less accurate and produce a lot more errors than human ribosomes. That is a benefit for simple, quickly reproducing life, which is also very vulnerable to the stresses of the molecular chemical environment. Unlike most more complex forms of life, which also have DNA repair mechanisms incorporated into the DNA polymerase, humans have these mechanisms. Some of these processes can often correct mistakes as soon as they are produced, while others can do so over time.
Regarding the pairing of C and T, etc. There are a number of balls in that room that, at first glance, appear to be identical, but if you compare two closely, you could find that one bump is larger or is located incorrectly even if it appears to be same. Proton shift is one such. Here are two instances using the purine guanine (G) and the pyrimidine thymine (T) (G). Please excuse my handwriting; I learned to type at a very young age. Shifted on the right, normal on the left. NA polymerase (as do most more complex forms of life) frequently correct mistakes as soon as they are made and others that correct mistakes later.
(ATTATCHMENT #1)
What kind of nuclear reaction is seen in (image)?
Answer:
Beta decay
Explanation:
A beta particle (also known as an electron) is being emitted from the nuclide.
How many grams MnO2 are needed
to generate 126.0 g Zn(OH)2?
Zn + 2MnO₂ + H₂O → Zn(OH)2 + Mn₂O3
The mass of manganese oxide (MnO2) that is needed to generate 126.0 g Zn(OH)2 is 220.56 g.
Mass of manganese oxide needed
The mass of MnO2 that is needed to generate 126.0 g Zn(OH)2 is calculated as follows;
Zn + 2MnO₂ + H₂O → Zn(OH)2 + Mn₂O3
From the reaction above;
2(87 g/mol of MnO₂) ---------> 99.4 g/mol of Zn(OH)2
174 ---------------------> 99.4
? -------------------------> 126
= (126 x 174)/99.4
= 220.56 g
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Answer:
220.56
Explanation:
state three differences between temporary and permanent changes
Answer:
temporary changes are the changes which are there only for a short period if time generally temporary changes are reversible permanent changes are the changes which remain to for longer time and are not reversible
Explanation:
hope it is helpful for
Give the formula of the compound formed from the following sets of elements,
- Calcium and Fluorine
- Hydrogen and Sulfur
- Nitrogen and Hydrogen
- Carbon and Chlorine
- Sodium and Oxygen
[tex]1) \text{ } \text{CaF}_{2}\\\\2) \text{ } \text{H}_{2}\text{S}\\\\3) \text{ } \text{NH}_{3}\\\\4) \text{ } \text{CCl}_{4}\\\\5) \text{ } \text{Na}_{2}\text{O}[/tex]
A box has dimensions of 2.5 cm by 3.0 cm by 4.0 cm. The volume of the box in milliliters and liters is Group of answer choices 3,000 mL and 3.0 L 30 mL and 30,000 L 7.5 mL and 7,500 L 30 mL and 0.030 L 7.5 mL and 0.0075 L
Considering the definition of volume, the volume of the box is 30 mL or 0.03 L.
What is volumeVolume is a metric magnitude that is defined as the extension in three dimensions of a region of space. In other words, it is defined as the amount of space occupied by the object or figure in three-dimensional space. Volume is measured in cubic units.
Volume can be considered as the capacity of a container to hold a quantity of fluid (gas or liquid).
Volume of a boxA box is a rectangular prism, which is defined as a prism with rectangular bases and rectangular lateral faces.
The volume of this prism depends on its three dimensions and is calculated as the multiplication of these dimensions:
Volume= Dimension 1× Dimension 2× Dimension 3
Volume of the box in this caseIn this case, you know that a box has dimensions of 2.5 cm by 3.0 cm by 4.0 cm. So, the volume can be calculated as:
Volume= 2.5 cm× 3 cm× 4 cm
Solving:
Volume= 30 cm³
Being 1 cm³= 1 mL and 1 L= 1,000 mL then:
Volume= 30 cm³= 30 mL= 0.03 L
Finally, the volume of the box is 30 mL or 0.03 L.
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What are some possible bias in an experiment about how sleep affects mood
HELP ASAPPPPP
Answer: Some possible bias in an experiment about how sleep affects mood could be a person's average mood with or without sleep, how people are acting in the experiment compared to how they actually would in their normal environment, or even how the person collected the data for the experiment interprets their moods.
Explanation:
1. A person's mood could be relatively different depending on other factors than just sleep, so it could affect experiment. For example if an emotional crisis had occurred recently, it could affect your mood and environmental factors could affected your mood, like weather.
2. A person could also change their mood around strangers or even when participating in the experiment. For instance if they aren't comfortable with the person taking down the analysist or the other test subjects, they make act differently than they usually do at home where they're comfortable.
3. A person collecting the data will have to know how to specify and determine a persons mood with their instruments. For example, if they're doing it just by talking with the test subjects, they'll have to know how to properly understand their different stages of each of their moods with out the data collectors mood changing as well. Also, if the data collectors mood is changed at all it can slightly affect the experiments results as well.
What is the chsrge of am atom with an equal number of protons and electrons
Answer:
0
Explanation:
they cancel each other out (ex: 1 positive and 1 negative cancels, making it neutral or a charge of 0)
HELP FAST PLEASE! If a reaction takes place and the theoretical yield is 73 g and the actual yield is 62 g, calculate the percent yield.
Choices:
A. 76%
B. 1.16%
C. 116%
D. 85%
Answer:
A
Explanation:
I think it's A. There are good answer for A.
What are the five (5) things that can indicate a chemical change has occurred?
Write out the combinations that indicate a chemical change, explain how you know.
Answer: Bubbles, burning, odor, color change, and rusting.
Explanation: Chemical changes are changes to something that is irreversible.
Justify that the shielding effect of an atom remain constant in a period but atomic size gradually gets smaller (chemistry)
Atomic size decreases across a period because but the positive charge of the nucleus gets increases across a period.
What is the shielding effect?The shielding effect is the shielding from the pulling force of the positively-charged nucleus given to. the outermost shell electrons by the inner electrons.
Since the shielding effect remains constant across a group but the positive charge of the nucleus gets bigger, atomic size decreases across a period.
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