Answer:
10 hours
Explanation:
Answer:
10
Explanation:
what is the density of 80 gram of a substance occupying a volume of 250 c.m cube at 25°C and 1 atmosphere?
Answer:
Density = 0.32g/mL
Explanation:
Density of a substance can be calculated using the formula:
Density (g/mL) = mass (g)/volume (mL)
According to the information provided in this question, mass of the substance = 80grams, volume = 250cm³/mL
Note that, the pressure and temperature are not needed to calculate the density of the substance.
Density = 80/250
Density = 0.32g/mL
Most neutral atoms of phosphorus have an atomic mass of 31 amu and an
atomic number of 15. What are these atoms composed of?
O A. 15 protons, 31 neutrons, and 15 electrons
B. 15 protons, 16 neutrons, and 15 electrons
C. 15 protons, 16 neutrons, and 16 electrons
D. 15 protons, 15 neutrons, and 15 electrons
Answer:b
Explanation:
don’t listen to the guy in the comments
The element contains 15 protons (atomic number), 15 electrons, and 16 neutrons (mass number minus atomic number).
What are protons, neutrons and electrons?The atomic number for any component exists as the number of protons in its atomic nuclei. In a neutral atom, the number of electrons exists exactly as the number of protons. The atomic mass (mass number) exists as the totality of the protons and neutrons in the nucleus. The mass number can change due to the particular that the number of neutrons can vary. Isotopes exists called for their mass numbers.
So, this element contains 15 protons (atomic number), 15 electrons, and 16 neutrons (mass number minus atomic number).
This isotope exists phosphorus - 31, which contains atomic number 15.
Therefore, the correct answer is option B. 15 protons, 16 neutrons, and 15 electrons.
To learn more about protons, neutrons and electrons refer to:
https://brainly.com/question/8480847
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Triassic, Jurassic, and Cretaceous: these are also divisions of the Mesozoic Era
Answer:
correct
Explanation:
thanks for being a smarty pants
What is the volume of 25 g of ethyl alcohol with a density of 0.79 g/mL?
Answer:
31.64...
Explanation:
The formula is volume is equal to mass over density.
So 25/0.79=31.64...
The volume of ethyl alcohol is 31.645mL.
What is volume?Volume is the amount of space the matter occupies.
What is ethyl alcohol?Ethyl alcohol is a clear, colourless liquid and the main ingredient in alcoholic beverages.
Density = mass/volume
D = m/v
v x D = m
On multiply both sides by D,
v x D/D = m/D
v = m/D
= 25g/0.79g/mL
= 31.645mL
Hence, the volume of ethyl alcohol is 31.645mL.
To learn more about volume and ethyl alcohol here
https://brainly.com/question/21009169
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Can someone help me with questions 4-5
21 points
4. describe three ways carbon dioxide was removed from the Earth's atmosphere.
Answer: Forests: Photosynthisis helps clear carbon dioxide naturally, Soils naturally store carbon, but agricultural soils are running a big deficit due to intensive use. Because agricultural land is so expansive, Bio-energy with Carbon Capture and Storage (BECCS) is another way to use photosynthesis to combat climate change. However, it is far more complicated than planting trees or managing soils — and it doesn’t always work for the climate.
5. Explain why there is now 21% Oxygen in the Earth's atomosphere compaired to little or no Oxygen in the Earth's atmosphere 4.5 billion years ago.
Answer: cientists believe that the Earth was formed about 4.5 billion years ago. Its early atmosphere was probably formed from the gases given out by volcanoes. It is believed that there was intense volcanic activity for the first billion years of the Earth's existence.The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. There were smaller proportions of water vapour, ammonia and methane. As the Earth cooled down, most of the water vapour condensed and formed the oceans.
Sorry its soooo long TwT
Which of the following pairs of compounds will react to form a precipitate? Why?
calcium chloride and silver nitrate
sodium iodide and potassium chloride
calcium chloride and sodium nitrate
Answer:
calcium chloride and silver nitrate
Explanation:
A precipitate is often formed in a double replacement reaction when the reaction yields an insoluble product.
Consider the reaction between calcium chloride and silver nitrate;
CaCl2(aq) + 2AgNO3(aq) -------->2AgCl(s) + Ca(NO3)2(aq)
AgCl is insoluble in water, hence the reaction leads to the formation of a precipitate.
We are ALWAYS conscious (aware) of why we decide to do the things we do:
True or false
Answer: true
Explanation:
a. How many moles of H2 are produced from two
moles of CH4 ?
Choose the formula for calcium silicate.
A: CaSiO3
B: Ca(SiO3)2
WILL MARK U BRAINLIEST. How many atoms of oxygen are found in one mole of naturally occurring oxygen gas (O2)? Is this different from the number of atoms found in one mole of pure solid iron? Be sure to explain your answer using reference to Avogadro's number.
Answer:
The atomic mass of each element is listed below the symbol of the element in the periodic table: Cu =
63.55 amu, Hg = 200.59 amu, S = 32.07 amu, and He = 4.00 amu. The mass of Avogadro’s number of atoms
is the atomic mass expressed in grams. Therefore, 6.02 × 1023 a
Explanation:
Baby Smiley has curly hair, but neither of her parents do. Is this possible?
Answer:
yes it was a one in four chance
Explanation:
An atom has 24 protons, 22 electrons, and 28 neutrons. What is the MASS # of the atom
The mass of an atom is given by the sum of the number of PROTONS and the number of NEUTRONS since ELETRON'S mass is negligible.
The mass is 24+28 = 52.
1. Cars use
to run, then they spit out carbon.
uhm they use gas/fuel to run
explain in complete sentences how a convection current is created
Answer:
Convection currents are caused by the movement of the magma in the mantle.
Explanation:
Which of the following is NOT a kitchen tool category?
A. Measuring
B. Convection oven
C. Food preparation
D. Cutting
Answer:
B. Convection oven
Explanation:
The following are all in a kitchen tool category;
I. Measuring: this includes tools such as tapes, scale (balance), graded-cup, teaspoon, which are used for taking measurements of food items in the kitchen.
II. Food preparation: it comprises of various tools used in the kitchen for the preparation of food. This includes pots, cooker, spoon, turner etc.
III. Cutting: these are tools used for cutting food items and it include knives, chopping board, grinder etc.
A convection oven is typically designed and developed with multiple fans for circulation of air and as such it is used for baking. It is mainly used in big industries and restaurants.
Emily and Patrick are trying to lift their friend hunter onto a tree branch. Emilio is pushing hunter upward with a force of 250 N. Patrick is pushing hunter upward with a force of 310N. Earth’s gravity is pulling Hunter downward with a force of 520 N
Assume all other forces on hunter are balanced. Which statement describes the forces on hunter ?
Answer:
The forces are unbalanced, so there is net force on the hunter.
Explanation:
To know which option is correct, we shall determine the net force acting on the hunter.
From the question given above, the following data were obtained:
Force applied by Emilio (F₁) = 250 N
Force applied by Patrick (F₂) = 310 N
Force of gravity (F₉) = 520 N
Next, we shall determine the total force applied in lifting the hunter. This can be obtained as follow:
Force applied by Emilio (F₁) = 250 N
Force applied by Patrick (F₂) = 310 N
Total force applied (Fₜ) =?
Fₜ = F₁ + F₂
Fₜ = 250 + 310
Fₜ = 560 N
Finally, we shall determine the net force acting on the hunter. This can be obtained as follow:
Force of gravity (F₉) = 520 N
Total force applied (Fₜ) = 560 N
Net force (Fₙ) =?
Fₙ = Fₜ – F₉
Fₙ = 560 – 520
Fₙ = 40 N
Thus the net force acting on the hunter is 40 N
From the calculations made above, we can see that the net force acting on the hunter is 40 N.
Therefore, the correct answer to the question is:
The forces are unbalanced, so there is net force on the hunter.
Plz help ASAP
Thx sm
Answer:
The answer is B!
Explanation:
Answer:
B
Explanation:
What is the molar mass of chlorine gas? (Hint: Be careful... the gas exists as Cl2)
Select one:
a. none of the above
b. 35.5 g
c. 71.0 g
d. 17.125 g
the calculation was like 70.90 so would it be none of the above??
Please Help me it’s balancing equations
Answer:
Blank 1: 1
Blank 2: 1
Blank 3: 2
Explanation:
I think the question is like this __Na2O +___H2O =___NaOH
I used "á" this word as equal sign. Is there any wrong with that?
if a solution is given to you, how will you determine whether it is acid,base or salt
Answer:
If your lab has litmus paper, you can use it to determine your solution's pH. When you place a drop of a solution on the litmus paper, the paper changes color based on the pH of the solution. Once the color changes, you can compare it to the color chart on the paper's package to find the pH.
Explanation:
A solution's pH will be a number between 0 and 14. A solution with a pH of 7 is classified as neutral. If the pH is lower than 7, the solution is acidic. When pH is higher than 7, the solution is basic. These numbers describe the concentration of hydrogen ions in the solution and increase on a negative logarithmic scale.
For example, If Solution A has a pH of 3 and Solution B has a pH of 1, then Solution B has 100 times as many hydrogen ions than A and is therefore 100 times more acidic.
oi oi oi oi oi help pls
Answer:
F
Explanation:
nonmetal doesn't conduct, is shiny and silver and is solid. Hope this helps :)
How is the periodic table useful today?
Answer:
The periodic table is useful today for finding out all the elements that exists on Earth. The elements there can be used to write down chemical formulas, calculate things like molar mass/atomic mass of each element, atomic number for each, number of valence electrons each element has, the oxidation number for each, etc. Lastly, it can be used to predict the properties of elements yet to be discovered.
Explanation:
Hope it helped!
Why is water considered a pure substance but orange juice a compound?
Answer: A mixture is when two or more substances combine physically together. However, in water, two hydrogen atoms combine with one oxygen atom chemically, forming a new substance that has properties different from hydrogen alone or oxygen alone. Therefore, water is not a mixture; it is a compound and it is pure. A Orange juice contains particles of solid (pulp) as well as liquid; it is not chemically pure. B Because its composition is not uniform throughout, orange juice is a heterogeneous mixture. A Aluminum oxide is a single, chemically pure compound. A Selenium is one of the known elements.
Hope this helps :)
Please help. I’m really struggling. No wrong answers please, if you don’t know it please don’t answer, I’m already failing the class.
Answer:
K₅Mn₅O₁₆
Explanation:
From the question given above, the following data were obtained:
Potassium (K) = 27.5 %
Manganese (Mn) = 37.5 %
Oxygen (O) = 35 %
Empirical formula =?
The empirical formula for the compound can be obtained as follow:
K = 27.5 %
Mn = 37.5 %
O = 35 %
Divide by their molar mass
K = 27.5 / 39 = 0.705
Mn = 37.5 / 55 = 0.682
O = 35 / 16 = 2.188
Divide by the smallest
K = 0.705 / 0.682 = 1
Mn = 0.682 / 0.682 = 1
O = 2.188 / 0.682 = 3.2 = 32/10 = 16/5
K = 1
Mn = 1
O = 16/5
Multiply by 5 to express in whole number
K = 1 × 5 = 5
Mn = 1 × 5 = 5
O = 16/5 × 5 =16
Thus, the empirical formula for the compound is K₅Mn₅O₁₆
Which of the following could affect infiltration of water into the surface of the soil? Explain in detail.
I. Concrete sidewalks
II. Parks and gardens
I WILL MARK AS BRAINLIST
Answer:
I. Concrete sidewalks
Explanation:
One of the factor that affects the infiltration of water into the surface of the soil is the use of concrete sidewalks.
A concrete sidewalk prevents water from infiltrating down into the soil profile. Infiltration deals with the movement of water into the soil or ground. It is the major source of ground water recharge. Also, infiltration makes water available for plants.Concrete is impermeable and non - porous media
When concrete pavements are used, water will not be able to move into the ground. They run on the surface and collects into nearby streams and water bodies.
HELPPP
The sum of percentage compositions must equal to 100 ±0.1.
True
False
Answer:
True
Explanation:
Pb has an atomic number of 82. It has an isotope Pb-207. The mass number is 207.
How many protons are in Pb 207?
O 82
125
O 207
none of these
Answer:
Number of protons = 82
Explanation:
Given data:
Atomic number of Pb = 82
Mass number of Pb-207 = 207
Number of protons = ?
Solution:
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.
Atomic number of Pb = number of protons or electrons
82 = number of protons or electrons
Mass number = Number of protons + number of neutron
207 = 82 + number of neutron
Number of neutrons = 207 - 82
Number of neutrons = 125
There are 12 liters of nitrogen gas in a sample. How many moles of N2 in this sample?
Answer:
0.54 moles of N2
Explanation:
First remember to find the volume in moles, 1 mole equals 22.4 liters.
So now use the dimensional analysis to show your work.
12 liters of N2 * 1 mol /22.4 liters of N2
Now calculate this. 12 * 1/22.4 or 12/ 22.4
12/22.4 = 0.535714286.
12 has two significant digits.
With that, The answer rounds to 0.54.
So that the final answer is 0.54 moles.
Hope it helped!
Calculate the number of formula units of KMnO4 in 100 mols
Answer:
100 moles of KMnO₄ contain 602.2 × 10²³ formula units.
Explanation:
Given data:
Number of moles of KMnO₄ = 100 mol
Number of formula units = ?
Solution:
The given problem will be solved through Avogadro number.
1 mole contain = 6.022 × 10²³ formula units
100 mol × 6.022 × 10²³ formula units / 1 mol
602.2 × 10²³ formula units
Thus, 100 moles of KMnO₄ contain 602.2 × 10²³ formula units.
ILL GIVE BRAINLEIST IF CORRECT:
A jeweler heats a silver strip and bends it into a bracelet. The jeweler then cools the bracelet. What happens to the particles when the strip of silver is heated?
(There may be more than one answer)
A. The particles move farther apart
B. The amount of particles increase
C. The particles get closer together
D. The particles move faster
Answer:
A
Explanation:
When the strip of silver is heated, the silver particles move farther apart.