Answer:
Origin
Explanation:
7. Base your answer to the following question on the information below and on your knowledge of biology A student designed an experiment to investigate a claim that athletes would have lower heart rates than nonathletes during exercise. After the students classified themselves as an athlete or a nonathlete, their resting pulses were determined. Then all the students performed the same exercise for four minutes and their heart rates were determined by recording the pulse rate in beats per minute. The students continued to measure their pulse rates for an additional four minutes. The average heart rate per minute for each group was determined. The data were recorded, as shown on the table below Average Heart Rate Response to Exercise (beats per minute) Time (minutes) Athlete Students Nonathlete Students Resting Pulse 68 72 1 76 78 2 82 90 Exercising Period 3 115 95 110 4 130 5 100 125 6 95 120 After Exercise 7 85 100 8 68 95 2.4 To improve the validity of the conclusion reached in this experiment, the students should repeat the experiment A) disregarding any data that don't fit the hypothesis B) with a larger number of athletes and nonathletes C) comparing the heart rates and breathing rates of males and females D) with the athletes doing different exercises than the nonathletes
why sodium and chlorine are active element
What is the mass of a lead block that has a volume of 30 mL?
O 3.39 grams
O .377 mL
O 265 mL
O 339 grams
Answer:
d
Explanation:
i think it's d, but I'm not sure. my answer is a little different but maybe i used a different number for the density of lead (11.35g/cc)
The oxidation # (charge) of an element called "lindenium "Ld is + 1 and the oxidation # (charge) of an element called "mendezine symbol "Mz, is -2. What is the chemical formula for the compound called lindenium mendezide?
Answer:
Ld₂Mz
General Formulas and Concepts:
Chemistry - Compounds
Valence shellsWriting chemical compoundsBalancing chargesExplanation:
Step 1: Define
"Lindenium" Ld w/ oxidation charge of +1
"Mendezine" Mz w/ oxidation charge of -2
Step 2: Write Compound
To balance out the charges to be neutral (0), we must counter balance the amount of Ld's with Mz's. We need 2 Ld's with 1 Mz to create a compound with a neutral charge:
2Ld¹⁺ + Mz²⁻
2(+1) + (-2) = (+2) + (-2) = 0 (neutral charge)
Therefore, our compound must be Ld₂Mz.
Reaction type
Li + N2
Li3N
Answer:
Combination or synthesis
Explanation:
The given reaction is:
6Li + N₂ → 2 Li₃N
This reaction is a synthesis or combination reaction. 6 moles of Li combines with nitrogen gas to produce 2 moles of Li₃N.
In a synthesis reaction, two substances combines together to give singular product. The formation of compounds from the union of the constituent elements falls into this category of reaction.What do the elements in group 18 have in common?
Answer: They are all odorless, colorless, monatomic gases with very low chemical reactivity.
Explanation: Plz give brainliest
PLEASE HELP
Electrical devices have been designed to convert electrical energy to other useful
forms of energy. Choose the device which converts electrical energy to kinetic
energy.
Answer:
B. Fan
Explanation:
The device in the options which converts electrical energy to kinetic
energy is the Fan.
When the fan is plugged to a an electric power source, the electrical energy gets converted to kinetic energy as a result of the movement of the blades in which Kinetic energy is defined as the energy as a result of the motion of a particle or substance.
A clear, pure liquid sample is brought into the lab and exposed to an electrical current. Different gases are
produced on each of the electrodes. The sample is -
a. an element
b. an alloy
c. a compound
d. a polymer
The sample here is a compound. The correct option is c.
What is a compound?A chemical compound is a substance made up of many identical molecules that contain atoms from more than one chemical element and are held together by chemical bonds.
A molecule made up of only one element's atoms is thus not a compound.
The anode undergoes oxidation, while the cathode undergoes reduction. The species being oxidized provides the electrons.
An electrode in an electrochemical cell is referred to as an anode or a cathode depending on the direction of electron flow.
The electrode reacts with the electrolyte at the anode, producing electrons.
These electrons build up at the anode. Meanwhile, another chemical reaction occurs at the cathode, allowing that electrode to accept electrons.
Thus, the correct option is c.
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Mercury is an element that forms during _____
Answer:
forms of mercury
Explanation:
Answer:
Explanation:
Mercury is an element and a metal that is found in air, water, and soil.Mercury rarely occurs uncombined in nature, but can be found as droplets in cinnabar (mercury sulfide) ores. China and Kyrgyzstan are the main producers of mercury. The metal is obtained by heating cinnabar in a current of air and condensing the vapour.
hope this helps! Have a good day or night! :)
equivalent mass of AL2O3
Answer:
[tex]Mass = 102g[/tex]
Explanation:
Given
Compound: [tex]Al_2O_3[/tex]
Required
Determine the equivalent mass
In the above compound, we have: 2 Al and 3 (O)
The atomic mass of Aluminium is:
[tex]Al = 27[/tex]
The atomic mass of Oxygen is:
[tex](O) = 16[/tex]
So, the equivalent mass is:
[tex]Mass = 2 * 27 + 3 * 16[/tex]
[tex]Mass = 54 + 48[/tex]
[tex]Mass = 102g[/tex]
Your explanation should include a claim, evidence, and scientific reasoning based on the data provided and the process of photosynthesis.
Answer:
yuh 100% true dude
Explanation:
...............
About ______ impact the creators have been recognized on earth.
A) one thousand
B) 50
C)500
D)150
C3H5OH + 3 O2 --> CO2 + H2O When balancing the equation above, how many molecules of CO2 and H2O are produced? The first half is already balanced.
Answer:
1.8069*10²⁴molecules of CO₂ and H₂O are produced.
Explanation:
C₃H₅OH + O₂ → CO₂ + H₂O
The law of conservation of matter states that since no atom can be created or destroyed in a chemical reaction, the number of atoms that are present in the reagents has to be equal to the number of atoms present in the products.
Then, you must balance the chemical equation. For that, you must first look at the subscripts next to each atom to find the number of atoms in the equation. If the same atom appears in more than one molecule, you must add its amounts
Left side: 3 C, 6 H and 3 O.
Right side: 1 C, 2 H and 3 O.
The coefficients located in front of each molecule indicate the amount of each molecule for the reaction. This coefficient can be modified to balance the equation, just as you should never alter the subscripts.
By multiplying the coefficient mentioned by the subscript, you get the amount of each element present in the reaction.
So, balancing the C:
C₃H₅OH + O₂ → 3 CO₂ + H₂O
Then:
Left side: 3 C, 6 H and 3 O.
Right side: 3 C, 2 H and 7 O.
Now, balancing the H:
C₃H₅OH + O₂ → 3 CO₂ + 3 H₂O
Then:
Left side: 3 C, 6 H and 3 O.
Right side: 3 C, 6 H and 9 O.
Finally, balancing the O:
C₃H₅OH + 4 O₂ → 3 CO₂ + 3 H₂O
Then:
Left side: 3 C, 6 H and 9 O.
Right side: 3 C, 6 H and 9 O.
Since you have the same amount of each element on each side of the reaction, the reaction is balanced. Then 3 moles of CO₂ and 3 moles of H₂O are produced.
Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole and it applies to any substance.
Then the following rule of three applies: if 1 mole contains 6.023*10²³ molecules, then 3 moles of CO₂ or 3 moles of H₂O, how many molecules does it contain?
[tex]amount of molecules=\frac{3 moles* 6.023*10^{23} molecules}{1 mole}[/tex]
amount of molecules= 1.8069*10²⁴
1.8069*10²⁴ molecules of CO₂ and H₂O are produced.
What is the mass of 2.25 mol of the element Iron (Fe)?
Choose the correct set up from the given choices.
a. You would divided 2.25 mol by (55.84 mol divided by 1 gram)
b. You would multiply 2.25 mol by (1mol divided by 55.84 g)
c. You would multiply 2.25 mol by (55.84g divided by 1 mol)
d. You would divide 2.25 mol by (1 mol divided by 55.84g)
Mole measure the number of elementary entities of a given substance that are present in a given sample. To find mass of 2.25 mol of the element Iron (Fe), we multiply 2.25 mol by (55.84g divided by 1 mol). Therefore option c is correct option.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance.
Mathematically,
Mole of Fe element= mass of Fe element÷ Molar mass of Fe element
mass= Mole of Fe element ×Molar mass of Fe element
Substituting the given values in above formula we get
mass= 2.25 mol× 55.84 g/mole
mass= 2.25 mol× 55.84 g/mole
To find mass of 2.25 mol of the element Iron (Fe), we multiply 2.25 mol by (55.84g divided by 1 mol).
Therefore option c is correct option.
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1. How many moles of Mg are there in 9.20 x 1024 atoms of Mg?
Answer:
15.28 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{9.20 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 15.282392..[/tex]
We have the final answer as
15.28 molesHope this helps you
Use the periodic to fill in the numbers in the electron configurations shown below.
B: 1s2 2sA2pB
A =
2
B =
1
Na: 1s22sC2pD3sE
Answer:
B: 1s²2s²2p¹
Na: 1s²2s²2p⁶3s¹
Explanation:
A = 2
B = 1
C = 2
D = 6
E = 1
Hope that helps.
Answer:
B: 1s2 2sA2pB
A = 2
B = 1
Na: 1s22sC2pD3sE
C = 2
D = 6
E = 1
How many rings/energy levels would the Bohe model for an element
have if it had 12 electrons?
PLEASE HELP
A can of cola contains approximately 240 calories. If you consume two cans of cola each day for one week, approximately how many calories did you consume from cola?
Select one:
a. 3,400 calories
b. 70 calories
c. 1,700 calories
d. 480 calories
How much radium-226 will remain from a 20 gram sample after 4800 years?
Answer:
2.5 g mass of Ra-226 will remain after 4800 years.
Explanation:
Given data:
Mass of Ra-226 = 20 g
Sample remain after 4800 years = ?
Solution:
Half life of Ra-226 = 1600 years
Number of half lives passed = T elapsed / half life
Number of half lives passed = 4800 year / 1600 year
Number of half lives passed = 3
At time zero = 20 g
At first half life = 20 g/2 = 10 g
At 2nd half life = 10 g/2 = 5 g
At 3rd half life = 5 g/2 = 2.5 g
Thus, 2.5 g mass of Ra-226 will remain after 4800 years.
someone help me plz :))) brainliest
Answer:
Option 2
Explanation:
Choose two different particles found in the air. Explain how they are different and how they are the same
Answer:
Dust and smoke.
Explanation:
Dust and smoke are two different particles present in the air. Dust and smoke are different from one another due to their origin. Smoke formed from burning of materials while dust refers to the soil particles lifted by the wind due to their light weight. Dust and smoke are similar to each other due to their small in size, infinite number means uncountable and light weight.
Air is a mixture of gases and consists of dust particles and water vapor. It consists of small to very large size of particles. Some of them include dust pollen, soot, and liquid droplets.
Dust and soot particles of the air are different as the soot is a fine black particle of carbon and tar. It is made by the incomplete combustion of air. While dust is fine dry particles of matter.Hence they both differ.
Learn more about the two different particles found in the air.
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Please Help!
Which change takes place at the freezing point of a substance?
Group of answer choices
A. A gas becomes a liquid
B. A solid becomes a gas
C. A liquid become a solid
D. A gas becomes a solid
please also give me an explanation since I do not understand this.
Answer:
❤C. A liquad becomes a solid❤
Explanation:
✌When you freeze water its a scientific fact that it becomes solid.✌
Help pls!
How can you use a chemical reaction to remove a contaminant from a solution?
Answer:
reverse osmosis
Explanation:
Water treatment is often complicated because it deals with the chemical makeup of the water, which varies widely. The first step is to determine what contaminants should be removed. Unfortunately, this is not always a straightforward process. Many contaminants make themselves known in obvious ways, such as iron or hydrogen sulfide, which can cause taste and odor issues. Other contaminants, such as arsenic or pesticides, are only uncovered through a sophisticated laboratory analysis.
It is important to test the water so that the right type of treatment system can be selected. Keep in mind, however, that more than one analysis may be necessary to get a baseline because water quality fluctuates. More information on possible contaminants in a specific area can be obtained by talking to residents, the local health department, the water department, or the state geological society. In addition, your laboratory should be able to recommend appropriate tests based on a customer’s concerns and the information provided about the water source. It is important not only to address customers’ concerns but also to educate them about potential contaminants they may not have considered.
HELPP ASAP
What do the colors on the periodic table show?
A. which element it is
B. the metallic properties of the element
C. the types of compounds the element can make
D. whether the element is a solid, a liquid, or a gas at room temperature
Answer:
Periodic tables can use color to identify other element characteristics. For example, an electronegativity periodic table color codes the elements based on how electronegative they are. The valence periodic table uses color to identify the most common valence state for each element.Oct 2, 2019
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The color given to a the elements in periodic table is to characteristics of the elements mainly to identify whether they are solid, gas or liquid. Thus option D is correct.
What is periodic table?A periodic table contains all the discovered elements which are classified into different groups and periods. Groups are vertical columns of elements with similar properties and same number of valence electrons.
Periods are horizontal rows from left to right with an increase in atomic number. There are 18 groups and 7 periods in periodic table. Each group has given each color and some elements showing exceptional characteristics such as hydrogen and helium have separate colors.
All the first group elements called alkali metals have one color and the second groups elements with another color, All the d-block elements are given the same colour and metals in p-block elements have the same color.
Similarly, all the metalloids have one color and all other gases have the same colour in which inert gas group and halogen group have seperate colours.
Hence, the color in periodic table helps to identify the element's nature like its state also. Thus option D is correct.
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what is love made out of ?
what makes one of your cells you ?
Which of the following scenarios would not prompt the cell to start dividing
Answer:
what r the options??????
ill attach a picture
Answer:
35.50
Explanation:
There are two stable isotopes, 35Cl (75.77%) and 37Cl (24.23%), giving chlorine a standard atomic weight of 35.45
Which has a higher frequency: microwaves or blue light? How do you know?
Answer:
Microwaves
Explanation:
Microwaves have more energy than blue light
Among microwaves or blue light, blue light has a higher frequency. This is because blue light belongs to the visible region has a short wavelength and produces a higher amount of energy.
What is the relationship between frequency and wavelength?The frequency of any wave is inversely related to the wavelength. This means that when the frequency of the wave increases, the wavelength decreases. While the relationship between frequency is directly related to the energy.
According to the context of this question, gamma rays have the highest frequency and shorter wavelength, while radiowaves have a shorter frequency and the highest wavelength.
Therefore, blue light has a higher frequency. This is because blue light belongs to the visible region has a short wavelength and produces a higher amount of energy.
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What is the difference between chlorine -35 and chlorine -37?
Answer:
Free chlorine involves the amount of chlorine that's able to sanitize contaminants, while combined chlorine refers to chlorine that has combined directly with the contaminants. Total chlorine is basically the sum of free chlorine and combined chlorine.
Explanation:
chlorine -35 being chlorine
chlorine -37 being free chlorine