Answer:
Wash your hands thouroughly with soap and water
Explanation:
Guessing. Hope I get it right for a brainly
Answer:
B C E
Explanation:
are all correct
Anton van Leeuwenhoek used a microscope to observe
tiny creatures swimming in a drop of pond water.
How did his observations contribute to the cell theory?
A. He showed that living cells come from other living cells.
B. He was the first person to observe and identify living cells.
C. He was the first person to observe dead plant cells.
D. He showed that all plants and animals are made of cells.
Answer:
b
Explanation:
A 1.0 m solution of a compound with 2 ionizable groups (pka's = 6.2 and 9.5; 100 ml total) has a ph of 6.8. what are the concentrations of the relevant acid and conjugate base?
Answer:
[H₂A] = 0.2M
[HA⁻] = 0.8M
Explanation:
A compound with 2 ionizable groups has as equilbriums:
H₂A ⇄ HA⁻ + H⁺ ⇄ A²⁻ + H⁺
A pH of 6.8 is near to the first equilibrium:
H₂A ⇄ HA⁻ + H pKa = 6.2
To determine concentrations of the acid H₂A and conjugate base HA⁻ we use H-H equation:
pH = pKA + log [HA⁻] / [H₂A]
6.8 = 6.2 + log [HA⁻] / [H₂A]
0.6 = log [HA⁻] / [H₂A]
3.981 = [HA⁻] / [H₂A] (1)
As concentration of the buffer is 1.0M:
1M = [HA⁻] + [H₂A] (2)
Replacing (2) in (1):
3.981 = 1- [H₂A] / [H₂A]
3.981[H₂A] = 1 - [H₂A]
4.981 [H₂A] = 1
[H₂A] = 0.2M
And [HA] = 1M - 0.2M = 0.8M
A small snail makes a journey that takes him in a circle of area 0.750square meters in one day. What is the area of the circle that the snail makes in square inches? Round to three significant figures. Do not give the units in your answer.
Answer:
1160
Explanation
1 square meter = 1550 square inches
[tex].0750 square meters * \frac{1550 square inches}{1 square meter}[/tex] = 1162.5 becomes 1160 when rounded to 3 sig figs.
The area of the circle of 0.750 m² is equivalent to 1.16 × 10³ in².
We want to convert 0.750 m² to in². We will use the conversion factor 1 in = 0.0254 m, squared.
[tex]0.750 m^{2} \times (\frac{1in}{0.0254m} )^{2} = 1.16 \times 10^{3} in^{2}[/tex]
The area of the circle of 0.750 m² is equivalent to 1.16 × 10³ in².
You can learn more about unit conversion here: https://brainly.com/question/19420601
what does H2CO3 mean on the periodic table
Answer:
Carbonic acid
Best of luck
It takes Serina 0.25 hours to drive to school. Her route is 16 meters long. What is
Serina's average speed on her drive to school? *
Answer:
60 (1 hour) × 0.25 = 15 minutes
15 ÷ 16 = 0.9375 meters per minute
In what state of matter do the particles spread apart and fill all the space availble to them?
a)energy
b)liquid
c)solid
d)gas
An atom has an atomic number of 16 and a mass number of 33.
What is the symbol of the element?
How many protons does the atom contain
How many neutrons does the atom contain?
How many electrons does the atom contain?
Answer:
sulfur
Explanation:
protons: 16 neutrons: 16 electrons: 2,8,6 i hope this helps!
a sample of a substance has a mass of 52.5g and displaces a volume of 4.2ml. what is the density of the substance
Answer:
Density = 12.5 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
From the question
mass = 52.5 g
volume = 4.2 mL
Substitute the values into the above formula and solve for the density
We have
[tex]Density = \frac{52.5}{4.2} \\ [/tex]
We have the final answer as
Density = 12.5 g/mLHope this helps you
You are making sweet tea. You add 56g of sugar into 78g if tea. What is the mass percent of sugar ?
Answer:
Approximately 72%
Explanation:
[tex]Sugar = 56g\\Tea's \:mass = 78g\\\\Sugar\:mass\:percentage = \\\frac{56}{78} \times 100\\\\\frac{5600}{78} \\\\=71.79\\Approximately \:72\%[/tex]
What is the mass of substance that exactly fills a 247.2 mL container? The density of the substance is 0.81 g/mL. Give the answer with two decimals.
Answer:
mass = 200.23 gExplanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]
Since we are finding the mass
mass = Density × volumeFrom the question
Density = 0.81 g/mL
volume = 247.2 mL
Substitute the values into the above formula and solve for the mass
mass = 0.81 × 247.2
= 200.232
We have the final answer as
mass = 200.23 g to 2 decimal placesHope this helps you
What has mass?
A. Energy
B. Heat
C. Light
D. Matter
Answer:
matter
Explanation:
Answer:
matter is your answer
hope this helped
A 36.04 g sample of water is boiled. When the steam expands to fill the vessel how many atoms of hydrogen would be found in the sample?
Answer:
The number of hydrogen atoms in 36.04 g sample of steam is 2.408 × 10²⁴ atoms of hydrogen
Explanation:
The given parameters are;
The mass of the sample of water, H₂O = 36.04 g
From the principle of conservation of matter, the mass of the water = The mass of the steam, therefore;
The mass of the steam = 36.04 g
The molar mass of H₂O = 18.01528 g/mol
Therefore, the number of moles, n, of H₂O in the 36.04 g of steam is given as follows;
n = Mass/(Molar Mass) = (36.04 g)/(18.01528 g/mol) = 2.00052399963 ≈ 2 moles
The number of molecules of H₂O per mole of H₂O is geven by the Avogadro's number = 6.02 × 10²³ molecules
Therefore;
The number of H₂O in 2 moles of H₂O = 2 × 6.02 × 10²³ = 1.204 × 10²⁴ molecules
The number of hydrogen atoms per molecule of H₂O = 2 hydrogen atoms
Therefore;
The number of hydrogen atoms in the 1.204 × 10²⁴ molecules of H₂O = 2 × 1.204 × 10²⁴ molecules of H₂O
Which gives;
The number of hydrogen atoms in the 1.204 × 10²⁴ molecules of H₂O = 2.408 × 10²⁴ atoms of hydrogen
Therefore;
The number of hydrogen atoms in 36.04 g sample of steam = 2.408 × 10²⁴ atoms of hydrogen.
what is the atomic number, mass number, element symbol, group number, and period number for oxygen?
Answer:
Atomic no. = 8
Mass no. = 16
Period no. = 2
Group no. = 6
What is the mass of an object when the volume is 50.0mL and the density is 1.5g/mL
4.One rubber tire can generate about250,000 BTUS (1BTU=.0003KW ) when it is burned. The average American home consumes about 10,000 kWh of electricity per year. How many tires would be needed to meet the annual electricity demand of ten homes for one year if the production of electricity from tires is 50% efficient??
Answer:
The number of tires required to power ten homes for one year is approximately 2,730 tires
Explanation:
The given information are;
The energy generated by burning one rubber tire = 250,000 BTUs
1 BTU = 0.0003 kW
The amount of energy consumed by the average American home = 10,000 kWh
Therefore, the amount of energy generated by burning one tire in kW can be found as follows;
The energy generated by burning one rubber tire = 250,000 BTUs
1 BTU = 0.0003 kW
∴ 1 BTU × 250,000 = 250,000 BTUs = 0.0003 kW × 250,000 = 75 kW
We note that 250,000 BTUs is equivalent to 263764 kJ
1 kWh is equivalent to 3600 kJ
10,000 kWh = 10,000 × 3600 = 36,000,000 kJ
The energy requirement for ten homes for one year = 10 × 36,000,000 kJ = 360,000,000 kJ
At 50% efficiency, the energy produced per tire = 0.5 × 263764 kJ = 131,882 kJ
The electrical energy produced per tire = 131,882 kJ/tire
The number of tires required to power ten homes for one year = 360,000,000 kJ/ 131,882 kJ/tire = 2,729.71293 ≈2,730 tires
The number of tires required to power ten homes ≈2,730 tires.
Is the number 5 x 10-4 greater or less than 1.0?
Answer:
Greater
Explanation:
14C is an isotope of carbon that possesses:_______ a) 6 protons, 8 neutrons, and 2 electrons. b) 6 protons, 6 neutrons, and 2 electrons. c) 6 protons, 8 neutrons, and 6 electrons. d) 8 protons, 6 neutrons, and 2 electrons. e) 6 protons, 2 neutrons, and 6 electrons.
Answer:
Option C. 6 protons, 8 neutrons and 6 electrons.
Explanation:
14C has the following:
Mass number = 14
Atomic number = 6
Next we shall determine the number of protons in 14C. This can be obtained as follow:
Atomic number is simply the number protons in an atom. Thus,
Proton = Atomic number
Atomic number = 6
Proton = Atomic number = 6
Proton = 6
Next, we shall determine the number of neutrons in 14C. This can be obtained as follow:
Mass number = proton + neutron
Mass number = 14
Proton = 6
Neutron =.?
Mass number = proton + neutron
14 = 6 + neutron
Collect like terms
Neutron = 14 - 6
Neutron = 8
Finally, we shall determine the number of electrons in 14C.
This can be obtained as follow:
Since the isotope i.e 14C has no charge, it means that the atom is in it's ground state. Hence, the number of protons and the number of electrons are the same i.e
Electron = proton
Proton = 6
Electron = proton = 6
Electron = 6
From the above calculations, 14C has
6 protons, 8 neutrons and 6 electrons.
Every Methane molecule looks different. True or false?
please use vocabulary that i can understand
Answer:
False
Explanation:
Molecules of the same substance are made up of the same type of atoms and look exactly alike.
Hence, if I have two molecules of methane having exactly the same atoms of carbon and hydrogen,the both are indistinguishable from each other based on appearance.
Hence all molecules of methane are exactly alike if they are composed of atoms of the same isotope of hydrogen and carbon.
Why are the trends and exceptions to the trends in ionization energy observed? Check all that apply. -Ionization energy tends to increase down a group because the electrons get farther away from the nucleus. -Ionization energy tends to increase across a period because the nuclear charge increases. -Ionization energy tends to increase across a period because electrons are added to the same main energy level. -The ionization energies of the elements in Group 16 tend to be slightly smaller than the elements in Group 15 because the fourth electron is added to an unfilled p orbital. -The ionization energies of elements in Group 13 tend to be lower than the elements in Group 2 because the full s orbital shields the electron in the p orbital from the nucleus.
Answer:
2, 3, 5
Explanation:
just the person above
The correct answer is the Ionization energy tends to increase across a period because electrons are added to the same main energy level and the ionization energies of elements in Group 13 tend to be lower than the elements in Group 2 because the full S orbital shields the electron in the p orbital from the nucleus.
What is causing the ionization energy trend?The first ionization energy increases as you move left to right across a period on the periodic table. This is because when the nuclear charge rises, the outermost electron has become more tightly connected to the nucleus.Learn more about Ionization energy here:
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Circle the molecule(s) in the atmosphere that come from animals. (circle all that apply)
a. Carbon dioxide, CO,
b. Helium, He
c. Methane, CH
d. Oxygen, O2
Answer:
A and C
Explanation:
A; Animals inhale and exhale, breath oxygen, leave carbon dioxide.
C; We fart, so do they! (farts are a release of methane gas from our bodies) Just ask my dog...
Hope this helped!
The molecule(s) in the atmosphere that comes from animals is -
a. Carbon dioxide, CO2c. Methane, CH4Humans and other animals contribute to the atmospheric gas cycle such as nitrogen gas, oxygen gas, carbon dioxide, and other gases. Animals give up mainly two gases in the atmosphere that are:
Carbon dioxide: during cellular respiration, animals release carbon dioxide as a waste product with energy. This carbon dioxide is removed from the body of animals to the atmosphere.Methane is a gas that is also released by the animals to the atmosphere but in very low concentration or quantity. During the digestion process, methane gas is formed in the digestion tract. methane will be released as burp mainly.Thus, the molecule(s) in the atmosphere that comes from animals is -
a. Carbon dioxide, CO2c. Methane, CH4Learn more about:
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Which part of an atom is mostly empty space?
A) Nucleus
B) Proton cloud
C) Electron cloud
D) Neutron
Answer:
Answer is C. Electron cloud
Explanation:
<3
Dmitri Mendeleev developed a chart-like arrangement of the elements called the ______ . He stated that if the elements were listed in order of increasing ______, their properties repeated in a regular manner. He called this the ______ of the elements. The arrangement used today differs from that of Mendeleev in that the elements are arranged in order of increasing ______. Each horizontal row of elements is called a(n) ______. Each vertical column is called a(n) ______, or , because of the resemblance between elements in the same column, a(n) ______.
Answer:
Explanation:
Dmitri Mendeleev developed a chart-like arrangement of the elements called the Periodic Table ______ . He stated that if the elements were listed in order of increasing atomic mass______, their properties repeated in a regular manner. He called this the periodicity of properties ______ of the elements. The arrangement used today differs from that of Mendeleev in that the elements are arranged in order of increasing atomic number______. Each horizontal row of elements is called a(n)period ______. Each vertical column is called a(n) column_____, or , because of the resemblance between elements in the same column, a(n) __group____.
1. Dmitri Mendeleev developed a chart-like arrangement of the chemical elements called the: periodic table.
2. According to Dmitri Mendeleev, the properties of chemical elements are repeated in a regular manner, if the chemical elements were listed in order of increasing: atomic mass.
3. Dmitri Mendeleev called the increasing order of chemical elements on the periodic table: the Periodic Law of the elements.
4. The arrangement used today differs from that of Dmitri Mendeleev in that the chemical elements are arranged in order of increasing: atomic number.
5. Each horizontal row of chemical elements is called a: period.
6. Each vertical column is of chemical elements is called a: group.
7. Because of the resemblance between chemical elements in the same column, each vertical column is called a: family.
Dmitri Ivanovich Mendeleev was a Russian chemist and inventor who was born on the 8th of February, 1834 in Tobolsk, Russia.
He formulated the Periodic Law and devised the periodic table of chemical elements.
The Periodic Law of chemical elements stated that the properties of all chemical elements are repeated in a regular manner, provided the chemical elements were arranged (listed) in order of increasing atomic mass.However, the modern periodic table of chemical elements differ because the chemical elements are arranged in order of increasing atomic number.On a periodic table, each horizontal row of chemical elements is called a period while each vertical column is of chemical elements is called a group.
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4) Which is a characteristic of a solution? * Its particles scatter light. Its particles are evenly distributed. Its particles settle out.
Answer: The correct answer is B. It’s particles are evenly distributed. (:
Explanation:
Answer:
b
Explanation:
how do groups and periods on the periodic table differ??
Answer:
Periods are horizontal rows while the groups are the vertical columns on the periodic table.
Which particles contribute to the atomic number and why ??
Answer:
the number of protons in the nucleus that are found in an atom is what determines an element's atomic number.why you may ask and thats because Protons contribute to the mass of an atom.(along with neutrons but they dont have a charge)but protons provide a positive charge to the nucleus.
Explanation:
because the atom is electrically neutral, the number of electrons must equal the number of protons.
The particles that contribute to the atomic number are the number of protons. Protons contribute to the atomic number because it is positively charged and present inside the nucleus. The correct option is c.
What is the atomic number?The quantity of protons in an atom's nucleus is known as the atomic number. The number of protons determines an element's identity. The atomic number contributes to the number of protons.
There are three subatomic particles present inside the particles. These are electrons, protons, and neutrons. The electron is negatively charged, a proton is positively charged, and a neutron is neutral.
Because the atom is electrically neutral, the number of electrons must equal the number of protons.
Thus, the correct option is c. protons.
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The question is incomplete. Your most probably complete question is given below:
a. atoms
b. neutrons.
c. protons.
d. electrons.
If a falling rock undergoes a Δv of 112ms due to an a¯¯¯ of 9.8 m/s2, how long did it fall? A. 6.7 seconds B. 11.4 seconds C. 0.09 seconds D. 9.8 seconds
Answer:
11.4
Explanation:
You wont fail your quiz .
If a falling rock undergoes a Δv of 112ms due to a speed of 9.8 m/s2, it will take 11.4 seconds to fall.
What is speed?The speed is the rate of change of position of an object with a given time of interval or per unit time then it is known as speed and it is the ratio of distance traveled to the time taken unit is meter per second.
The speed of an object is 9.8 m/s² distance traveled is 112m/s so the time will be,
Speed = distance / time
Substituting the value,
Time = distance/ speed
Time = 9.8 m/s² / 112m/s
Time = 11.4 seconds
Therefore, it will take 11.4 seconds to fall, if a falling rock undergoes a Δv of 112ms due to a speed of 9.8 m/s².
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Which of the folling ion or atom has smallest size?
a. CI
b. CI-
c. K
d. K+
71. Chloroform is a liquid once used for anesthetic. What is the volume of 5.0 g of chloroform. The density of chloroform is 1.49 g/mL.
Answer:
Volume, V = 3.35 mL
Explanation:
Given that,
The density of chloroform is 1.49 g/mL
We need to find the volume of 5.0 g of chloroform. Let V is its volume.
Density is equal to mass per unit volume.
[tex]d=\dfrac{m}{V}\\\\V=\dfrac{m}{d}\\\\V=\dfrac{5\ g}{1.49\ g/mL}\\\\V=3.35\ mL[/tex]
So, the volume of 5 g of chloroform is 3.35 mL.
what can you say about the average distance from the nuclease of an electron the 2's orbital as compared with a 3s orbital
Answer:
A 3s orbital is at a greater average distance from the nucleus than a 2s orbital
Explanation:
As the principal quantum number n increases, the distance of the orbital from the nucleus increases. Hence if we consider the 2s and 3s orbitals, it is easy to see that the 3s orbital is at a greater distance from the nucleus than the 2s orbitals.
This is clearly seen when we plot the radial distribution against the distance from the nucleus. This enables us to visualize the region in space in which an electron may be found.
Students are experimenting with a substance that they
think can be added to soil to increase the number of
flowers a certain plant will make. They set up 20 pots of
soil, each planted with the same type of seed. They
divide the pots into two groups and add 15 drops of the
substance to pots in one group and only 10 drops to pots
in the other group. After the plants grow for four weeks,
the students count how many flowers each plant has
made
What does this experimental investigation lack?
a control group
an independent variable
a dependent variable
a procedure
Answer:
A: Control Group
Explanation:
The control group is part of an expierment left untouched by anything that could possibly alter it, in the case of this question, the students have two groups of plants that have drops of liquid that could alter them, in order to see the growth, and to see if the liquid actually did anything, in order to do so, you would have to have a untouched plant, that shows what it looks like with out any alteration from researchers. So the answer would be control group.
Answer:
i think control group?
Explanation:
meow x3 UwU