Answer:
Reactants have more energy than products
Explanation:
Generally, in an exothermic reaction heat is released. In other words, energy is released. So you start with reactants which have a set amount of stored chemical energy, and you lose some in the reaction. Since energy is 'leaving', the stored chemical energy in the products is less than what we started with in the reactants. When given a graph, you can tell this is true because going from left to right, the line representing the stored chemical energy will start at a higher level than where it ends.
The true statement about an exothermic reaction is that reactants have more energy than products.
What is an exothermic reaction?An exothermic reaction is one in which the energy of reactants is greater than that of products. As such, energy is given off during the reaction in form of heat.
Thus, the true statement about an exothermic reaction is that reactants have more energy than products.
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How many moles are in 15.62g of P?
Answer:
[tex]\boxed {\boxed {\sf 0.5043 \ mol \ P}}[/tex]
Explanation:
To convert from moles to grams, we must use the molar mass. This is found on the Periodic Table. Look for Phosphorous or P.
Phosphorus (P): 30.973762 g/molWe can use this number as a ratio.
[tex]\frac{30.973762 \ g \ P }{1 \ mol \ P}[/tex]
Multiply by the given number of grams: 15.62
[tex]15.62 \ g \ P *\frac{30.973762 \ g \ P }{1 \ mol \ P}[/tex]
Flip the fraction so the grams of phosphorus cancel.
[tex]15.62 \ g \ P *\frac{1 \ mol \ P}{30.973762 \ g \ P }[/tex]
[tex]15.62 *\frac{1 \ mol \ P}{30.973762 }[/tex]
[tex]\frac{15.62 \ mol \ P}{30.973762 }[/tex]
Divide.
[tex]0.504297799 \ mol \ P[/tex]
The original measurement of grams has 4 significant figures, so our answer must have the same.
For the number we calculated, that is the ten thousandth place. The 9 in the hundredth thousandth place tells us to round the 2 to a 3.
[tex]0.5043 \ mol \ P[/tex]
There are 0.5043 moles of phosphorus in 15.62 grams.
Salinity affects density. Choose all of the correct answers.
options:
As water temperature decreases, water density increases.
As water temperature increases, water density increases.
As concentration of salt increases, water density also increases.
As concentration of salt decreases, water density also increases.
Answer:
1 and 3 i think so i could be wrong
Salinity affects density in the following instances:
A. As water temperature decreases, water density increases.
C. As concentration of salt increases, water density also increases.
What is salinity?Salinity can be defined as a measure of the amount of salt that is dissolved in a water body. Thus, it mainly measured in gram per liters.
What is density?Density can be defined as mass per unit volume. Also, it is measured in kilogram per cubic meters.
Based on scientific records, salinity affects density in the following instances:
As the temperature of water decreases, the volume increases and as such water density increases.As concentration of salt increases, water density also increases due to an increase in the mass of the water.Read more on salinity here: https://brainly.com/question/20283396
An atom that has lost one or more electrons is a(n) _____.
Not Cation
Answer:
ion
Explanation:
that is the definition according to g o o g l e:
"an atom or molecule with a net electric charge due to the loss or gain of one or more electrons."
Answer:
An ION
Explanation:
Because a positive ion is called a CATION and a negative ion is called an ANION (Please brainlist me)
Which of the following describes an adaptation?
A. a place where an organism lives
B. something that does not help an organism survive
C. something that improves an organism's ability to survive
D. a part of the animal's life cycle
Answer: C something that improves an organisms ability to survive
Answer:
C.
Explanation:
What types of chemical
reactions can change a toxic
chemical into one that is less
toxic
Answer:
Very toxic materials are substances that may cause significant harm or even death to an individual if even very small amounts enter the body.There are a number of very toxic materials that may be used in workplaces. Some examples include carbon monoxide, hydrogen sulfide, chlorine and sodium cyanide
Explanation:
here are generally four types of toxic entities; chemical, biological, physical and radiation: Chemical toxicants include inorganic substances such as, lead, mercury, hydrofluoric acid, and chlorine gas, and organic compounds such as methyl alcohol, most medications, and toxins.
The highly toxic chemical compounds can be changed to less toxic one by suitable substitution reactions where, a functional group which less hazardous but having the same biochemical properties are substituted for the new product.
What is toxicity?Toxicity of a chemical is its ability to cause serious health risks which can strike a single cell. Exposure to toxic chemicals may even lead to death. The dose of toxicity depends on the structure and reactivity of the chemicals.
Also the adverse effect of each toxic chemicals depends on the way of exposure, and the amount of exposed chemical. There are some methods to detoxify a living body if any toxic is intaken. Suitable antidotes are given for them.
The toxicity generated in a chemical might be originated from a certain structure or group. Thus, by altering that group for instance substituting a ring or removing them ir substituting a functional group that is responsible for the toxicity will make the chemical less toxic.
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2) A student determined the melting point of a substance to be 55.2DC. If the accepted value
is 50.1C, what is the percent error in the student's determination?
A) 12.0 B) 5.10 C) 10.2 D) 9.24
Answer:
C) 10.2
Explanation:
Formula: Actual-Expected/Expected
The actual was 55.2 while the expected was 50.1
55.2-50.1/50.1=0.101796407 * 100= 10.2%
The percentage error in the student's determination is 10.2%
The correct answer to the question is Option C. 10.2
From the question given above, the following data were obtained:
Measured value = 55.2 °C
Accepted value = 50.1 °C
Percentage error =?Next, we shall determine the absolute error. This can be obtained as follow:
Measured value = 55.2 °C
Accepted value = 50.1 °C
Absolute error =?Absolute error = |Measured – Accepted|
Absolute error = |55.2 – 50.1|
Absolute error = 5.1Finally, we shall determine the percentage error.
Absolute error = 5.1 °C
Accepted value = 50.1 °C
Percentage error =?[tex]Percentage error = \frac{Absolute error }{Accepted value} * 100\\\\= \frac{5.1}{50.1} * 100\\\\[/tex]
Percentage error = 10.2%Therefore, the percentage error in the student's determination is 10.2%.
The correct answer to the question is Option C. 10.2
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4 Al + 3 O2 -> 2 Al2O3 How much aluminum would be needed to completely react with 45 grams of Oz?
Answer:
50.6g Al would be needed
Explanation:
Based on the reaction:
4Al + 3O₂ → 2Al₂O₃
4 moles of aluminium react with 3 moles of oxygen to produce 2 moles of Al₂O₃
To solve this question we need to find the moles of 45g of O₂. Then using the chemical equation find the moles of Al and its mass:
Moles O₂ -Molar mass: 32g/mol-:
45g O₂ * (1mol / 32g) = 1.41 moles O₂
Moles Al:
1.41 moles O₂ * (4mol Al / 3mol O₂) = 1.875 moles Al
Mass Al -Molar mass: 26.98g/mol-:
1.875 moles Al * (26.98g / mol) =
50.6g Al would be needed
The amount of aluminum that would be required to completely react with 45 grams of O2 would be 50.59 grams.
From the balanced equation of the reaction:
[tex]4 Al + 3 O_2 ---> 2 Al_2O_3[/tex]
The mole ratio of Al to O2 is 4:3.
Mole of 45 grams of O2 = mass/molar mass
= 45/32
= 1.4063 moles
Equivalent mole of Al: 4 x 1.4063/3
= 1.875 moles
mass of Al = mole x molar mass
= 1.875 x 26.98
= 50.59 grams
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what are the the examples of amphoteric oxide
Answer:
Many metals (such as zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Amphoterism depends on the oxidation states of the oxide. Al2O3 is an example of an amphoteric oxide.
Answer:
Lead (II) oxide and zinc (II) oxide
1 How does a hydroelectric plant work to produce electricity? List the steps below.
2 How is the way that a wind turbine works similar to the way that a hydroelectric
plant works? How is it different?
Answer:
1. -Hydropower plants capture the energy of falling water to generate electricity
-a turbine converts the kinetic energy of falling water into mechanical energy.
- a generator converts the mechanical energy from the turbine into electrical energy.
2. In the case of a wind-electric turbine, the turbine blades are designed to capture the kinetic energy in wind. The rest is nearly identical to a hydroelectric setup: When the turbine blades capture wind energy and start moving, they spin a shaft that leads from the hub of the rotor to a generator.
Explanation:
hope this kinda helped.
Antarctica is a frozen land so cold and I see no changes in Wheeler scientist have discovered fossils
Answer:
The correct answer is - due to the movement of plates it is relocated.
Explanation:
Antarctica is a very cold part of the earth, it is so cold that there is no growth of trees or such vegetation. Even though there are no or less vegetation scientists found fossils of the trees.
It is relocated from the north where the conditions were warmer and easy for tree growth. It is then moved due to plate movements to the south pole. This is the reason behind the fossils scientist found.
An isotope of an element has 95 protons and 146 neutrons. What is the symbol for this
element?
Answer:
238 is the answer
Explanation:
238 - 146 + 3 = 95
Americium (95Am) is an element that has 95 protons and 146 neutrons in its nucleus of an atom.
What is Americium (95Am)?Americium is an element that has 95 protons and 146 neutrons. Its symbol is Am. Its atomic mass is 241 amu which is get by addition of proton and neutron.
So we can conclude that Americium (95Am) is an element that has 95 protons and 146 neutrons in its nucleus of an atom.
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14. An increase in temperature results in an increase in ...
(there are two correct answers)
A.Water molecules
B.The melting point
C.Pressure
D.Fun
Answer: its C. and B.
Explanation:
hopes this helps
what is the name of the atom with 16 protons, 15 neutrons and 18 electrons
What are the number of atoms in gallium
Answer: 31! hope this helps!
Explanation:
Which is the last element in the periodic table?
Answer:
Oganesson!
It is a synthetic chemical element with the symbol Og and atomic number 118. It was first synthesized in 2002 at the Joint Institute for Nuclear Research in Dubna, near Moscow, Russia, by a joint team of Russian and American scientists.
Answer:
the last element is ogasnesson
Name the technique used to separate oil from water and also the principle involved in the separation.
The technique used to separate oil from water is known as decantation.
Oil has less density compared to that of water.
By the process of decantation we can separate mixtures by removing a liquid layer that is free of a precipitate.
What happens to the air temperature if you add extra CO2?
Answer:
Adding more CO2 to the atmosphere will cause surface temperatures to continue to increase. However, more energy is absorbed in the weaker bands and in the wings of the strong band, causing the surface and lower atmosphere to warm further.
2) Where is Earth, exactly? Use this image to find our location. Earth is
Located in the
A) Norma arm
B) Outer arm
C) Orion spur.
D) Galactic bar
Answer:
C) Orion spur.
The Orion Arm is a minor spiral arm of the Milky Way Galaxy that is 3,500 light-years across and approximately 10,000 light-years in length, containing the Solar System, including Earth.
which alkene will most likely have the highest boiling point
a. ethene
b. hexane
c. pentene
d. propyne
Answer:
B. hexane
Explanation:
Im not sure I just goggled it
Answer:
A. Ethene
Explanation:
Ethene, propene and the various butenes are gases at room temperature. All the rest that you are likely to come across are liquids. Boiling points of alkenes depends on more molecular mass (chain length). The more intermolecular mass is added, the higher the boiling point
Students in Ms. Brown demonstrated several chemical reactions but the data did not represent the law of conservation of matter in
any of the four experiments. Kai and Maria are about to add 3 grams of magnesium (Mg) to a test tube of 30 grams of hydrochloric
acid (HCI). They covered their container with a balloon as a seal. If the girls expect a chernical change as well as evidence of the
Law of conservation of matter, choose ALL of the predictions that are appropriate?
A)
There will be a rapid evolution of gas.
B)
The mass of the products will equal 339.
The solid magnesium metal will disappear.
D)
The balloon covering the container will expand.
E)
There will be a dramatic change in temperature,
Answer:
Answer: everything except E
Explanation: There was no dramatic change in temperature and i just took the assignment.
According to the law of conservation of matter, matter cannot be created not be destroyed. In this experiment, no matter loss will occur but there will be rapid evolution hydrogen gas and the balloon will expand.
What is conservation of matter?According to conservation of matter, matter can neither be created nor be destroyed but its state and properties can be changed. The total mass of the reactants will be equal to the total mass of the products.
Magnesium is a second group element and is a metal. Metal reacts with hydrogen halides to form metal halides and hydrogen gas as the reaction written below:
[tex]Mg +2 HCl \rightarrow MgCl_{2} +H_{2}[/tex]
The evolved hydrogen gas in this reaction tries to diffuses out the sealing and thus the balloon cover expands. And thus the solid magnesium metal disappears to form magnesium chloride.
The evolution of gases is exothermic and therefore, the temperature outside increases suddenly. There we can see bubbles of hydrogen in the reaction system.
Therefore, the changes that occur in the experiments are, rapid evolution of gases, solid metal disappears, sealing cover expands and there occur a rapid change in temperature. Thus options A,C,D,E are correct.
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2Na(s) + Cl2(g) → 2NaCl(s)
Which of the following choices shows the correct Lewis electron-dot diagram for a molecule of chlorine, Cl2?
Answer: 2!
Explanation:
The best lewis structure for [tex]Cl_2[/tex] is in option 2.
Na or sodium is the cation in the reactant.
Cl or chlorine is the anion in the reactant side.
NaCl is the product of the reaction.
Lewis Structure is a very simplified representation of the valence shell electrons in a molecule. It is used to show how the electrons are arranged around individual atoms in a molecule. Electrons are shown as "dots" or for bonding electrons as a line between the two atoms.
Chlorine is a group VIIA element in the periodic table and contains seven electrons in its last shell.
Valence electrons are given by chlorine atoms = [tex]7\times2=14[/tex]
Total valence electrons = 14
So, each of Cl is surrounded by three pairs of dots, connected by a single line. So, the best lewis structure for [tex]Cl_2[/tex] is in option 2.
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Which of the following do not have a nucleus? *
bacteria
virus
both bacteria and viruses do NOT have a nucleus
both bacteria and viruses DO have a nucleus
Answer:
C
Explanation:
bacteria and virus do not have nucleas. so C
if my answer helps please mark as brainliest.
Electrons can occur only in specific
Answer: Electrons have wavelike motion and are restricted to certain energy states associated with specific wavelengths.
if a sample of 4.50 moles of hydrogen gas was reacted with excess nitrogen, how many moles of ammonia gas would be produced?
Answer: 3.00
Explanation: got the answer from my teachers notes
According to stoichiometry, if a sample of 4.50 moles of hydrogen gas was reacted with excess nitrogen, 3 moles of ammonia gas would be produced.
What is stoichiometry?Stoichiometry is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.
Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.It is useful in balancing chemical reactions.In the given reaction 3 moles hydrogen gives 2 moles ammonia, thus, 4.5 moles of hydrogen will give, 4.5×2/3=3 moles.
Thus, if a sample of 4.50 moles of hydrogen gas was reacted with excess nitrogen, 3 moles of ammonia gas would be produced.
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A temperature of 37C is equivalent to a temperature of
Answer:
98.6 Degrees Fahrenheit
Explanation:
To convert from Celsius to Fahrenheit, the formula is F=(1.8*C)+32. Since C=37 in this case, our formula is F=(1.8*37)+32. First, solving the work in the parentheses, 1.8*37=66.6. Adding that will get you to 98.6, so F=98.6.
the more massive an object is, the more
Answer:
it have more more mass, gravitational potential energy
Explanation:
3. How many grams of water will be produced from 15.0 grams of Methane? *
CH4 +2 02 → CO2 + 2H2O
hey y’all, I’m growing a plant for science class but I need some questions about the plant, can someone please give me atleast 3 questions to answer for it..
Hurry pls <3
Answer:
What four things do all plants need?
What are the parts of the plant?
What does the root do for the plant?
What does the stem do for the plant?
What do leaves do for the plant?
The plant parts that take in water and minerals from the soil are?
What is the first stage in the growth of many plants?
Explanation:
:)
how do you identify an acid from its chemical formula
Explain why laboratory safety rules are important.
it's for a essay please help!!!!!!
Answer:
Laboratory safety rules are important because there can be many dangerous chemicals in a lab. Safety rules help people stay safe when they are in close contact with these chemicals. Over the past few years, lab safety rules have prevented many deaths. It's important to follow these rules because you could get seriously injured if you don't.
Hope that helps! Good luck! :)
