Answer:
1.65hr
Explanation:
Given parameters:
Number of labs = 5 labs
Time taken = 3 minutes
Unknown:
Time taken in hours to grade 165 labs = ?
Solution:
Let us find the rate of the teacher;
Rate = [tex]\frac{number of labs}{time}[/tex]
Insert the parameters and solve;
Rate = [tex]\frac{5}{3}[/tex] = 1.67labs/min
Now;
Time to grade 165 labs = [tex]\frac{number of labs}{rate}[/tex]
Time to grade 165 labs = [tex]\frac{165}{1.67}[/tex] = 98.8min
Since;
60min = 1hr
98.8min = [tex]\frac{98.8}{60}[/tex] = 1.65hr
Knowledge of the functioning of cells and DNA has led to the creation of new life in laboratories. What is an example of an ethical question this raises?
a) Why are cells and DNA important to study?
b) How do cells create new life?
c) How many cells do humans have?
Is it wrong to change or control life forms?
Answer:
Explanation:
It’s D
Answer:
D. Is it wrong to change or control life forms?
Explanation:
edge 2021 :P
A student wants to develop a model of an organism's cell that lacks chloroplasts. Which statement BEST explains how the lack of chloroplasts affects an organism?Your answer:An organism that lacks chloroplasts would not be able to convert sunlight into chemical energy through photosynthesis.An organism's cells would not be able to reproduce since the chloroplasts contain the genetic material.An organism that lacks chloroplasts would not be able to manufacture all the protein required by its cells
Recall that the main function of chloroplasts is to convert sunlight to chemical energy, or to carry out photosynthesis. Plant (and eukaryotic algae) cells contain these organelles, while animal cells do not, and hence, animals cannot carry out photosynthesis.
So, a lack of chloroplasts would mean that an organism would not be able to convert sunlight into chemical energy through photosynthesis.
Plants cells, and specifically the chloroplast organelle, are able to absorb sunlight, and together with CO₂ and water, produce glucose (for the plant to eat) and oxygen (which is released into the atmosphere). That glucose is further broken down by the plants' mitochondria. Animals directly consume the glucose to be broken down and converted into energy, hence why we do not have - nor need - chloroplasts in our cells.
What evidence always shows that a chemical change has happened?
O A. The total mass of material changes.
O B. A new substance is produced.
C. A solid material dissolves in a liquid.
O D. A liquid changes into a solid.
Answer:
B. A new substance is produced.
Explanation:
In chemical changes, you will always have a new end product from the reactants that were used within the process.
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Please Help!!!
Which of the following is not a good indication that a chemical change has occurred?
A. The formation of gases
B. A change in color
C. A scratched surface
D. The release heat or light
Answer:
C.
Explanation:
Please HELP ME please it would be amazing if you can!!
Answer:
i think 4
Explanation:
Answer:
i guess number 4
Explanation:
5)
Experiments with gold foil indicated that atoms
A)
usually have a uniform distribution of positive charges
B)
usually have a uniform distribution of negative charges
C)
contain a positively charged, dense center
D)
contain a negatively charged, dense center
Answer:
c
Explanation:
I just learned all this in chemistry too lol
got 100 on the test last week so its good
Experiments with gold foil indicated that atoms contain a positively charged, dense center and the correct option is option C.
Experiments with gold foil, known as the Rutherford gold foil experiment, were conducted by Ernest Rutherford in 1911. In this experiment, he bombarded a thin gold foil with alpha particles.
Most of the alpha particles passed through the foil with little deflection, but some of them were deflected at large angles, and a small fraction even bounced back. This observation led Rutherford to conclude that the atom contains a positively charged, dense center called the nucleus, where most of its mass is concentrated. He proposed the nuclear model of the atom, which became a significant advancement in the understanding of atomic structure.
Thus, the ideal selection is option C.
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A state property X has a value 89.6 units. It undergoes the following changes, first increase by
3.6 units, then increase by another 18.7 units, then decrease by 12.2 units and finally attains a
value of 85.5 units The value for this series of change is A) 14.2 units
B) -4.1 units C) 108.3 units
D) uncertain
Answer:
B) -4.1 units
Explanation:
According to this question, a state property X has a value 89.6 units. It undergoes the certain changes as follows:
- first increase by 3.6 units
- then increase by another 18.7 units
- then decrease by 12.2 units
- and finally attains a value of 85.5 units
This can be mathematically represented by 89.6 - {3.6 + 18.7 - 12.2 - x) = 85.5
To get x, we say;
89.6 + 3.6 = 93.2
93.2 + 18.7 = 111.9
111.9 - 12.2 = 99.7
99.7 - 85.5 = 14.2units.
The changes that occured is represented as follows:
= (3.6 + 18.7) - (12.2 + 14.2)
= 22.3 - 26.4
= -4.1 units
if the atomic mass is 14 and the atomic number is 7,how many neutrons do you have?
Answer: 7 neutrons
Explanation: Atomic number refers to the number of protons in the nucleus of the atom. Also you can treat atomic mass as how many particles (protons and neutrons) are in the nucleus of the atom. So for this problem:
14 particles - 7 protons = 7 neutrons (and we know all that's left over is neutrons because we subtracted all the protons)
Why are flowers brightly colored?
Answer: In order to help the plants reproduce, flowers that are bright in color are meant to attract birds, bees and other insects. In the genetics of a flower, bright or dull colors are set in
Explanation:
A cylinder fitted with a piston has 10 dm3
of a gas 27ºC. How can you double the pressure
by varying the temperature only?
Answer:
go to the website quizlet it will help you!!!!!!!!
Explanation:
What is the best definition of biology?
A. The study of energy and light
B. The study of matter
C. The study of applied science
D. The study of living things
Answer:
D. The study of living things
Explanation:
prefix "bio-" means life, living things
The scientist philosopher Aristotle is known as the father of biology. The best definition of biology is the study of living things. The correct option is D.
What is biology?The branch of science which deals with the study of living organisms, their origins, anatomy, morphology, and distribution is known as the biology. Biology is a natural science discipline which studies living things.
The study of living things and their important processes is explained in biology. This field deals with all the physiochemical aspects of life. It is sub divided into other branches like botany, physiology and zoology.
Thus the correct option is D.
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Give a scenario in which a good conductor would come in handy.
Explanation:
Not sure if ment like an electric type that gives off energy but here is my answer. a good conductor comes off handy in every situation. meaning, without one a machine, or whatever the conductor is being used for could be unstable, or not be able to work perfectly. which would could lead to certain malfunctions. so a good conductor could also give you a better chance of succeeding.
I WILL GIVE BRANLIEST What factor is the temperature in an ecosystem? Abiotic or Biotic?
Answer:abiotic .
Explanation:
Which of the following equations is not balanced?
Explanation:
i think the answer is first and last
What else is produced during the combustion of butane, C4H10?
2C4H10 + 13O2 8________ + 10H2O
Answer:
CO2
Explanation:
What type of conspiracy did Apple take part in?
There is sufficient evidence to show that Apple violated Section 1 of Sherman Act by making publishers raise price of e-books.
Explanation:
Determine the final temperature of a system, if 120 grams had an initial temperature of 80°C and mixes with 3,000 g of water at an initial temperature of 20°C
Answer:
The final temperature of the mixture is 22.3°C
Explanation:
Assuming that the 120 g substance at 80°C is water, final temperature of the mixture can be determined using the formula:
Heat lost = Heat gained
Heat = mc∆T where m is mass, c is specific heat capacity of water, and ∆T is the temperature change = Tfinal - Tinitial.
Let the final temperature be T
Heat lost = 120 × c × (T - 80)
Heat gained = 3000 × c × ( T - 20)
Equating the heat lost and heat gained
120 × c × -(T - 80) = 3000 × c × (T - 20)
9600 - 120T = 3000T - 60000
60000 + 9600 = 3000T + 120T
69600 = 3120T
T = 69600/3120
T = 22.3°C
Therefore, the final temperature of the mixture is 22.3°C
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Answer:
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If the atomic number of Lithium is 3 and its mass number is 7, how many protons, electrons, and neutrons does a neutral
atom of Li have
Answer:
Protons = 3
Neutrons = 4
Electrons = 3
Explanation:
For every atom, the atomic number is equal to the number of protons.
In a neutral atom (atom with no charge) the number of protons is equal to the number of electrons.
To calculate neutrons subtract the number of protons (atomic number) from the rounded molar mass:
7 - 3 = 4 neutrons
A chemist is identifying the elements present in a sample of seawater. What characteristic of an element’s atoms always determines the element’s identity?
A brick has a volume of 475 cubic centimeters and a mass of 912 grams. Calculate its
density.
Write your answer to the hundredths place
Answer:
1.92 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question we have
[tex]density = \frac{912}{475} \\ [/tex]
We have the final answer as
1.92 g/cm³Hope this helps you
A student has a remote control for a television. The student points the
remote at the television and presses a button on the remote labeled
Volume. A small red light flashes on the front of the remote. The student
observes that the sound from the television becomes lower.
Which statement best describes how the remote control communicates
with the television to change the volume of the sound?
a
Oь
Od
The remote control sends microwaves toward the television that are absorbed by the front of the television
The remote control sends low-energy infrared radiation to a light detector on the front of the television
The remote control sends radio waves in many directions, which bounce off the walls of the room toward the front of the
television
The remote control sends sound waves in many directions, which bounce off the walls of the room toward a vibration detector on
the front of the television
od
Answer:
The remote control sends low-energy infrared radiation to a light detector on the front of the television
Explanation:
The signal between a remote control and the TV controls consists of pulses of infrared light, which is invisible to the human eye
What is the mass of 0.9210 moles of sulfur dioxide gas (SO2)?
Answer:
58.944 g
Explanation:
From the question given above, the following data were:
Mole of SO2 = 0.9210 mole
Mass of SO2 =?
Next, we shall determine the molar mass of SO2. This can be obtained by adding the molar mass of sulphur and oxygen together as illustrated below:
Molar mass of SO2 = 32 + (2 × 16)
= 32 + 32 = 64 g/mol
Finally, we shall determine the mass of 0.9210 mole of SO2 as follow:
Mole of SO2 = 0.9210 mole
Molar mass of SO2 = 64 g/mol
Mass of SO2 =?
Mole = mass /Molar mass
0.9210 = mass of SO2 / 64
Cross multiply
Mass of SO2 = 0.9210 × 64
Mass of SO2 = 58.944 g
Thus, the mass of SO2 is 58.944 g.
When a 0.4500 g sample of impure potassium chloride was dissolved in water and treated with an excess ofsilver nitrate, 0.8402 g of silver chloride was precipitated. Calculate the percentage KCl in the original sample.
Answer:
97.78% KCl in the original sample
Explanation:
The % of KCl in the original sample would be as follows:
[tex]97.78[/tex]%
Given that,
Amount of sample of impure Potassium Chloride [tex]= 0.4500 g[/tex]
Amount of Silver Nitrate precipitated [tex]= 0.8402g[/tex]
Now,
Molarity of KCl = [tex]74.5 g/mol[/tex]
Minimum moles required for reaction [tex]= 0.0059 mol[/tex]
Final number of moles [tex]= 0.0059 mol[/tex]
So,
Concentration = Number of moles * Molarity
[tex]= 0.0059 mol * 0.74.5 g/mol\\= 0.440g[/tex]
Therefore,
% of KCl in the original Sample = Weight of Pure KCl/Weight of Impure KCl
[tex]= 0.440/0.450[/tex] × [tex]100[/tex]
[tex]= 97.78[/tex]%
Thus, [tex]97.78[/tex]% is the correct answer.
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what occurs at the cathode of a galvanic cell? (sorry about the picture my back camera is broken)
Answer:
The reduction half-reaction of a redox reaction
Explanation:
(just took the test)
The reduction of half-reaction of a redox reaction. Hence, option B is correct.
What is an electrolytic cell?An electrolytic cell converts electrical energy into chemical energy or vice versa.
A galvanic cell is an electrochemical cell in which chemical energy is converted to electrical energy. The chemical reaction which drives a galvanic cell is a redox reaction i.e. a reduction-oxidation process.
A typical galvanic cell is composed of two electrodes immersed in a suitable electrolyte and connected via a salt bridge. One of the electrodes serves as a cathode where reduction or gain of electrons takes place. The other half cell functions as an anode where oxidation or loss of electrons occurs. Batteries and fuel cells are examples of galvanic cells.
Hence, option B is correct.
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how do i caculate velocity
Answer:
Velocity Equation in these calculations:
Final velocity (v) of an object equals initial velocity (u) of that object plus acceleration (a) of the object times the elapsed time (t) from u to v.
Explanation:
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I will give brainiest who helps me with the correct answer
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5. Name the compound which contain Strontium, Fluorine, and Oxygen.
Options:
Strontium fluorate
Strontium fluoride
Strontium chlorate
Strontium fluorine
Answer:
The first option: Strontium Fluorate.
Explanation:
because Fluorine and oxygen combines to make fluorate, Strontium stays the same.
p.s: i need help in geo and there's an exam tomorrow.
How many moles are equal to 145 g of sodium carbonate?
Answer:
There are
0.0642 mol Na
2
CO
3
in
6.80 g
.
Explanation:
The chemical formula of sodium carbonate is
Na
2
CO
3
. The molar mass of sodium carbonate is
105.988439 g/mol
.
6. All changes in states of matter (freezing, evaporation, condensation, etc.) are
a. physical changes
b. chemical changes
Pretty sure its Physical Changes
No chemical reaction is happening.
Answer:
Changes of states are physical changes
Explanation:
They are reversible changes that do not involve changes in matter's chemical makeup or chemical properties.
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State the career function of mechanical engineering
Answer:
Mechanical engineers design power producing machines, like electric generators, internal combustion engines, and steam and gas turbines, also power using machines, such as refrigeration and air-conditioning systems. Mechanical engineers design other machines inside buildings, such as elevators and escalators.
Explanation: