Answers
Answer:
20.0 sec
you can use ln (2)=k* t1/2 then ln N2/N1=-k(t2-t1)
or just divide 100 by 2 then 50 by 2 then 25 by 2 then 12.5 by 2 and that is 4 half lifes at 5 secs each
Explanation:
Related Questions
4 Al + 3 O2 -> 2 Al2O3 How much aluminum would be needed to completely react with 45 grams of Oz?
Answers
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
More on stoichiometry calculations can be found here: https://brainly.com/question/22288091?referrer=searchResults
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
Answers
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:
:)
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.
Answers
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
if a sample of 4.50 moles of hydrogen gas was reacted with excess nitrogen, how many moles of ammonia gas would be produced?
Answers
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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B. Fill in the blanks with the correct answer. Choose from the choices inside the box.
1. The bones that protect the delicate organs of the body.
2. It is a long flat bone at the middle of the chest and attached to the ribs,
3. They are the bones that protrude at the base of the neck.
4, This bone connects the backbone and the legs.
5. This bone protects our brain.
6. This system of the body gives structural support and shape.
7. These muscles are connected to the bones and are responsible for movements.
8. These are involuntary muscles that are not attached to the bones.
9. These muscles are moving rhythmically, contracting and relaxing alternately to generate force to
pump blood throughout the body.
10. A system of the body that supports the skeleton and responsible for body movement.
Muscular system
skeletal system
smooth muscles
cardiac muscles
Skeletal muscles
hipbone
collarbone
axial skeleton breastbone
skull
Answers
Answer:
Answer:
Asan po yung choices?
Which is the last element in the periodic table?
Answers
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
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,
Answers
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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Antarctica is a frozen land so cold and I see no changes in Wheeler scientist have discovered fossils
Answers
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 atom that has lost one or more electrons is a(n) _____.
Not Cation
Answers
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)
Suppose your friend investigated the color of
pea pods and concluded that green pods (G) were
dominant over yellow pods (g). What experimental
evidence would be needed to support this
conclusion?
Help pls!!
Answers
Answer:
Wag kang tatalon Kasi malayu ang talunan mo
the more massive an object is, the more
Answers
Answer:
it have more more mass, gravitational potential energy
Explanation:
what is the name of the atom with 16 protons, 15 neutrons and 18 electrons
Answers
How many moles are in 15.62g of P?
Answers
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.
Electrons can occur only in specific
Answers
Answer: Electrons have wavelike motion and are restricted to certain energy states associated with specific wavelengths.
which alkene will most likely have the highest boiling point
a. ethene
b. hexane
c. pentene
d. propyne
Answers
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
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
Answers
Answer: C something that improves an organisms ability to survive
Answer:
C.
Explanation:
Explain why laboratory safety rules are important.
it's for a essay please help!!!!!!
Answers
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! :)
Disease and bacteria are spread when lab procedures are not followed. The instruments used by students and professionals must be fully cleaned and sterilized to prevent the dangerous spread of these diseases and bacteria
how do you identify an acid from its chemical formula
Answers
A temperature of 37C is equivalent to a temperature of
Answers
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.
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
Answers
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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Name the technique used to separate oil from water and also the principle involved in the separation.
Answers
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.
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?
Answers
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.
(1) How will you determine which dyes are present in the beverage that you have chosen to analyze?
(2) How will you determine the concentration of each dye present in the beverage?
(3) By what factor will you change the concentration as you monitor the absorbance/transmittance of the solution?
(4) Write a preliminary plan for your experimental procedure. Include what each member of your team will do as part of this plan.
Answers
3. How many grams of water will be produced from 15.0 grams of Methane? *
CH4 +2 02 → CO2 + 2H2O
Answers
According to molar weights :
16 gm CH4 + 64 gm O2 = 44 gm CO2 + 36 gm H2O
Since 16 gm CH4 produce 36 gm H2O
Hence 2.5 gmCH4 produce 36×2.5/16 gm H2O
= 5.265 gm of H2O
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Related Questions (More Answers Below)
An isotope of an element has 95 protons and 146 neutrons. What is the symbol for this
element?
Answers
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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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
Answers
Answer:
C
Explanation:
bacteria and virus do not have nucleas. so C
if my answer helps please mark as brainliest.
What are the number of atoms in gallium
Answers
Answer: 31! hope this helps!
Explanation:
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
Answers
Answer: its C. and B.
Explanation:
hopes this helps
what are the the examples of amphoteric oxide
Answers
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
2Na(s) + Cl2(g) → 2NaCl(s)
Which of the following choices shows the correct Lewis electron-dot diagram for a molecule of chlorine, Cl2?
Answers
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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