Answer:
By measuring through scale
Explanation:
CAN YOU TELL THE NAME OF COUNTRY BECAUSE I AM FROM NEPAL
Question: Which is the last step in excavation of the skeletal remains?
Answer options:
A: defining the investigation area
B: identifying the layout of the remains
C: exposing the remains
D: screening of the soil
E: lifting the remains
Answer:
B
Explanation:
No explanation needed for it i got 100% on it
Lifting the remains is the last step in the excavation of the skeletal remains. Therefore, option E is correct.
What is the excavation of the skeletal remains?In archaeology, excavation can be described as the exposure, processing, and recording of archaeological remains. An excavation site or "dig" can be the area being studied. These locations are from one to various areas at a time while a project can be conducted over weeks to several years.
Excavation involves the recovery of various types of data from a site. This data includes ecofacts, artifacts, features, and archaeological context. Before excavating, the presence of remains can often be suggested by remote sensings, such as ground-penetrating radar.
During excavation, stratigraphic excavation removes phases of the site one layer at a time and keeps the timeline of the material remains consistent. This is done through mechanical means and the soil is processed via methods like mechanical sieving or water flotation.
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piece of plastic has a mass of 6.9 kg and a volume of 722 cm3. What is its density in g/cm3?
Answer:
mass = 6.9 kg = 6900 g
volune= 722 cm3
density= mass/volume
density= 6900/722
= 9.55 g/ cm3
Answer:
[tex]\boxed {\boxed {\sf d \approx 9.56 \ g/cm^3}}[/tex]
Explanation:
We want to find the density of the plastic in grams per cubic centimeter.
Density is found by dividing the mass by the volume.
[tex]d=\frac {m}{v}[/tex]
We know the mass is 6.9 kilograms and the volume is 722 cubic centimeters We must convert kilograms to grams.
There are 1000 grams in 1 kilogram. [tex]6.9 \ kg *\frac{1000 \ g }{1 \ kg} = 6.9 * 1000 \ g= 6900 \ g[/tex]Now we know the mass and volume. Substitute the values into the density formula.
[tex]d=\frac{ 6900 \ g }{722 \ cm^3}[/tex]
[tex]d= 9.5567867 \ g/cm^3[/tex]
Let's round to the nearest hundredth. The 6 in the thousandth place tells us to round the 5 to a 6.
[tex]d \approx 9.56 \ g/cm^3[/tex]
The density of the plastic is about 9.56 grams per cubic centimeter
If the oxygen isotope 20O has a half-life of 15 seconds, what fraction of a sample of pure 20O remains after 1.0 minute?
Answer:
1/16
Explanation:
We have the half life of ²⁰O = 15 seconds
This half life means that the reactant 8s going to be half at this time
Now we have 60 seconds = 1 minute
Then in 60 seconds we are going to have 4 half life.
Then ²⁰O will be 1/2⁴
1/2⁴ = 1/16
This is the answer to this question.
Thank you!
1/16 fraction of a sample of pure ²⁰O remains after 1.0 minute
Given:
The half life of ²⁰O = 15 seconds
This half life means that the reactant 8s going to be half at this time
Now, we have 60 seconds = 1 minute
Then in 60 seconds we are going to have 4 half life.
Then ²⁰O will be 1/2⁴
1/2⁴ = 1/16
Thus, the fraction of a sample of pure ²⁰O remains after 1.0 minute is 1/16.
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-) A sample of oxygen had an initial volume of 25.0L and was at a standard pressure of
30atm, what would the new volume be if the pressure was increased to 55.00 atm?
Answer:
13.64 LExplanation:
The new volume can be found by using the formula for Boyle's law which is
[tex]P_1V_1 = P_2V_2[/tex]
From the question we have
[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]
From the question we have
[tex]V_2 = \frac{25 \times 30}{55} = \frac{750}{55} \\ = 13.636363...[/tex]
We have the final answer as
13.64 LHope this helps you
A chemist adds 485 mL of a 0.0025 mol/L calcium sulfate solution to a reaction flask. Calculate the mass in grams of calcium sulfate the chemist has added to the flask. Round your answer to significant digits.
Answer : The mass in grams of calcium sulfate is 0.16 grams.
Explanation :
Molarity : It is defined as the number of moles of solute present in one litre of solution.
Formula used :
[tex]Molarity=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution}}[/tex]
Solute is, [tex]CaSO_4[/tex]
Given:
Molarity of [tex]CaSO_4[/tex] = 0.0025 mol/L
Molar mass of [tex]CaSO_4[/tex] = 136 g/mole
Volume of solution = 485 mL
Now put all the given values in the above formula, we get:
[tex]0.0025=\frac{\text{Mass of }CaSO_4\times 1000}{136\times 485}[/tex]
[tex]\text{Mass of }CaSO_4=0.16g[/tex]
Thus, the mass in grams of calcium sulfate is 0.16 grams.
pLeeease help im so tired and i need to SLEEP. Answer the 1s you know
1. How does the mechanical energy of a ball that is starting to fall compare to its total energy just before it hits the floor?
2. When you stand in sunlight, what form of energy is emitted by the sun?
3. An eye doctor wants to design reading glasses that also function as sunglasses. Should the eye doctor use a reflective-transparent material or a reflective-opaque material for the lenses? Support your claim.
Please Urgent!! And please explain. :)
A chemist must dilute 87.0 mL of 1.61 M aqueous sodium carbonate (Na,Co,) solution until the concentration falls to 1,00 M. He'll do this by adding distilled water to the solution until it reaches a certain final volume.
Calculate this final volume, in liters. Round your answer to 3 significant digits.
Answer:
0.140 Liter
Explanation:
M1V1 = M2V2
M1 = 1.61 M
V1 = 87 ml
M2 = 1.00 M
V2 = ?
V2 = M1V1/M2
V2 = 1.61×87/1
V2 = 140.07 ml
V2= 0.140 L
Can you help me with this
Answer:
6
Explanation:
there are 2 sodium atoms, 1 carbon atom and 3 oxygen atoms
2+1+3=6 atoms
Answer:
seems like you got the answer already sooooooooooooooooooo
Explanation:
<3
Have a pic of Chenle dont hate
Write the following elements in decreasing order of atomic radius. Li, Cs, K, Rb
Answer:
Cs > Rb > K > Li
Explanation:
Given elements:
Li, Cs , K and Rb
Arrange in the the order of decreasing atomic radius:
Atomic radius is taken as half of the inter-nuclear distance (d) between two covalently bonded atoms of non - metallic elements or half of the distance between two nuclei in the solid state of metals.
Across a periodic table, atomic radii decrease progressively from left to right.Down a group atomic radii increases progressively due to the successive shells of electrons being added.So, the given species are the same group on the periodic table. These are group 1 elements;
Li, Cs , K and Rb
Cs > Rb > K > Li
using the periodic table complete the table to describe each atom type in your answers.
Answer:
A =8
B =8
C = O oxygen
D =26
E =30
F = Fe iron
Explanation:
No of protons = atomic number
No of protons + number of neutrons = atomic mass
Answer:
Using the periodic table, complete the table to describe each atom. Type in your answers.
A ⇒ 20
B ⇒ 40
C ⇒ Ca
D ⇒ 10
E ⇒ 9
F ⇒ F
Explanation:
yes
A 25.0 L gas cylinder at 32.0 is filled with 2.33 moles of carbon dioxide and 4.66 moles of nitrogen. Calculate the total pressure of the mixture. Then calculate the partial pressure of carbon dioxide in the cylinder
Answer:
P= 7.01 atm
P(CO₂)= 2.34 atm
Explanation:
Step 1: Convert the temperature to Kelvin
We will use the following expression.
K = °C + 273.15
K = 32.0°C + 273.15 = 305.2 K
Step 2: Calculate the total number of moles of the mixture
We will use the following expression.
n = nCO₂ + nN₂ = 2.33 mol + 4.66 mol = 6.99 mol
Step 3: Calculate the total pressure of the mixture
We will use the ideal gas equation.
P × V = n × R × T
P = n × R × T / V
P = 6.99 mol × 0.0821 atm.L/mol.K × 305.2 K / 25.0 L
P= 7.01 atm
Step 4: Calculate the partial pressure of carbon dioxide
We will use the ideal gas equation.
P(CO₂) × V = nCO₂ × R × T
P(CO₂) = nCO₂ × R × T / V
P(CO₂) = 2.33 mol × 0.0821 atm.L/mol.K × 305.2 K / 25.0 L
P(CO₂)= 2.34 atm
Question (2) If your car
gets 27.8 miles to the gallon, how many liters of gasoline are necessary to travel 112 km?
This problem can be solved in short steps or in one longer step. In either case, please show your work.
Use the following conversion factors:
1 mi = 1.609 km
1 gal = 3.785 L
PLEASE HELP!!!!
Answer:
You need to convert 27.8 miles to km and gallon to liters, then
(km/L) x #L = ?
27.8×112
=?
?×1gal
=?
?×1mi
=?
=?×?×?
answer
How are the aurora borealis formed?
Answer:
When the solar wind gets past the magnetic field and travels towards the Earth, it runs into the atmosphere .As the protons and electrons from the solar wind hit the particles in the Earth's atmosphere, they release energy – and this is what causes the northern lights.
Explanation:
Which statement about the periodic table is true?
a.Elements in the same column share similar properties.
b.Elements in the same row share similar properties.
c.Elements on the left have a larger nucleus than elements on the right.
d.Elements at the top of each column have the highest atomic mass in that column.
Answer
Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.
Statement that can be considered true as regards periodic table is : A: Elements in the same column share similar properties.
Periodic table can be regarded as the table that give the arrangements of the chemical elements into rows and columns.Option A is right because there is similar properties associated with elements in the same column, this is because there is the same valence electrons associated with them.Option B is wrong, there is no similar properties with element of same row. the same column share similar .Therefore, option A is correct.
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44.90 g of reactants are placed in a beaker
containing 45.00 g of water at 15.00 oC. At the end of the chemical reaction the temperature of the water rises to 25.00 oC. Calculate the energy change of the reaction rounded to the correct number of sig figs.
A
1900 J
B
-1900 J
C
1882 J
D
-1882
E
1884 J
F
-1884 J
PLS help lol
Answer:
D. -1882J
Explanation:
We can solve the energy released in a chemical reaction in an aqueous medium using the equation:
Q = -m*C*ΔT
Where Q is energy (In J),
m is mass of water (45.00g)
C is specific heat of water (4.184J/g°C)
And ΔT is change in temperature (25.00°C - 15.00°C = 10.00°C)
Replacing:
Q = -45.00*4.184J/g°C*10.00°C
Q = -1882J
Right answer is:
D. -1882J
The number of O atoms in 6.15 g of Al(PO 4 ) 3 (molar mass=122.00 g/mol) is
How many moles of dinitrogen tetroxide (N2O4) are in 6.49 x 109 particles?
1.08 x 10–14 mol N2O4
3.091 x 1033 mol N2O4
6.02 x 1023 mol N2O4
1.08 x 10–23 mol N2O4
Answer: There are [tex]1.08 \times 10^{-14}[/tex] moles [tex]N_{2}O_{4}[/tex] present in [tex]6.49 \times 10^9[/tex] particles.
Explanation:
According to the mole concept, 1 mole of a substance contains [tex]6.022 \times 10^{23}[/tex] particles.
Hence, number of moles present in [tex]6.49 \times 10^9[/tex] particles are calculated as follows.
No. of moles = [tex]\frac{6.49 \times 10^9}{6.022 \times 10^{23}}[/tex] mol
= [tex]1.08 \times 10^{-14}[/tex] mol
Thus, there are [tex]1.08 \times 10^{-14}[/tex] moles [tex]N_{2}O_{4}[/tex] present in [tex]6.49 \times 10^9[/tex] particles.
Answer:
1.08 × 10⁻¹⁴ moles of N2O4
Explanation:
Given data:
Moles of dinitrogen tetroxide = ?
Number of particles = 6.49×10⁹
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions , particles and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole contain 6.022 × 10²³ particles.
6.49×10⁹ particles × 1 mole / 6.022 × 10²³ particles
1.08 × 10⁻¹⁴ mol
What is the coefficient of Oxygen in the balanced reaction below:
__C2H4+ __O2--> CO2+ __H2O
The coefficient of Oxygen in the balanced reaction : 3
Further explanationGiven
Reaction(unbalanced)
C2H4+ O2--> CO2+H2O
Required
The coefficient of Oxygen
Solution
Give a coefficientC₂H₄+ aO₂⇒ bCO₂+cH₂O
C, left=2, right=b⇒b=2
H, left=4, right=2c⇒2c=4⇒c=2
O, left=2a, right=2b+c⇒2a=2b+c⇒2a=2.2+2⇒2a=6⇒a=3
The equation becomes :
C₂H₄+ 3O₂⇒ 2CO₂+2H₂O
determine molar concentration of the equivalent of acetic acid in 6% solution (d=1g/ml)
Molar concentration of acetic acid = 1 M
Further explanationGiven
acetic acid in 6% solution (d=1 g/ml)
Required
molar concentration
Solution
mass of acetic acid in solution
mass = density x %mass
mass = 1 g/ml x 6%
mass = 0.06 g/ml ⇒ 60 g/L
MW acetic acid = 60 g/mol
molarity acetic acid = mass : MW
molarity = 60 g/L : 60 g/mol
molarity = 1 mol / L = 1 M
Fossil fuels indirectly rely on what source for their energy?
A. the atmosphere
B. the sun
C. a carbon atom
D. Earth’s interior
Answer:
The sun
Explanation:
I did it and got it correct :-)
Suppose you start with one liter of vinegar and repeatedly remove 0.08 L, replace with water, mix, and repeat. a. Find a formula for the concentration after n n steps.
Answer:
0.92^n
Explanation:
Given that :
Initial amount of vinegar = 1 Litre
Number of litres removed repeatedly = 0.08 Litre
Since the amount removed each time is constant, then ;
Initial % = 100% = 100/100 = 1
. Using the relation :
Amount of vinegar in mixture :
Initial * (1 - amount removed / initial amount)^n
n = number of times repeated
1 * (1 - 0.08/1)^n
1 * (1 - 0.08)^n
1 * 0.92^n
Hence,
For nth removal,
Concentration will be :
0.92^n ; for n ≥ 1
100 POINTS! (50 split up) PLSSSSSSSSSS HELP!!! I REALLY NEED IT SO MUCH :( I PROMICE TO GIVE BRAINLIEST AND FIVE STARS AND A THANKS! 6TH GRADE SCIENCE! i used all my points for this!
You measure the mass of an apple using a balance. You get these three measurements:
Trial 1: 167.0 g
Trial 2: 166.9 g
Trial 3: 167.2 g
You know that the true mass of the apple is 172 g. Describe your results in terms of precision and accuracy. Explain your answer in a paragraph for the best grade.
Answer:
100 POINTS! (50 split up) PLSSSSSSSSSS HELP!!! I REALLY NEED IT SO MUCH :( I PROMICE TO GIVE BRAINLIEST AND FIVE STARS AND A THANKS! 6TH GRADE SCIENCE! i used all my points for this!
You measure the mass of an apple using a balance. You get these three measurements:
Trial 1: 167.0 g
Trial 2: 166.9 g
Trial 3: 167.2 g
You know that the true mass of the apple is 172 g. Describe your results in terms of precision and accuracy. Explain your answer in a paragraph for the best grade.
Explanation:
I NEED HELP. This is about science
Answer:
independent varible
Explanation:
True or false? Salt weathering is when salt spray from the sea gets into a crack in a rock. It may evaporate and crystallize, putting pressure on the surrounding rock and weakening the structure.
1. True
2. False
(GIVING BRAINLIEST)Which of the compounds below is an ionic salt?
A.) CIO^2
B.) CCl^4
C.) NO^2
D.) AIP
Answer:
is it c
Explanation:
Isotopes ____________ the atomic mass of an element because they have a ____________ number of neutrons.
a. disregard, constant
b. increase or decrease, different
c. increase, lower
d. decrease, higher
Answer:
) B
Explanation:
Suppose 275 g of NO3- flows into a swamp each day. What volume of CO2 would be produced each day at 17.0°C and 1.00 atm?
I attached the image of the equation for reference
Answer:
264.28 L of CO₂
Explanation:
We'll begin by calculating the number of moles present in 275 g of NO₃¯. This can be obtained as follow:
Mass of NO₃¯ = 275 g
Molar mass of NO₃¯ = 14 + (16×3) = 14 + 48 = 62 g/mol
Mole of NO₃¯ =?
Mole = mass / molar mass
Mole of NO₃¯ = 275 / 62
Mole of NO₃¯ = 4.44 moles
Next, we shall determine the number of mole of CO₂ produced from the reaction. This can be obtained as follow:
2NO₃¯ + 5CO + 2H⁺ —> N₂ + H₂O + 5CO₂
From the balanced equation above,
2 moles of NO₃¯ reacted to produced 5 moles of CO₂.
Therefore, 4.44 moles of NO₃¯ will react to produce = (4.44 × 5) / 2 = 11.1 moles of CO₂.
Thus, 11.1 moles of CO₂ were produced from the reaction.
Finally, we shall determine the volume of CO₂ produced each day. This can be obtained as follow:
Temperature (T) = 17 °C = 17 °C + 273 = 290 K
Pressure (P) = 1 atm
Number of mole (n) of CO₂ = 11.1 moles
Gas constant (R) = 0.0821 atm.L/Kmol
Volume (V) of CO₂ =?
PV = nRT
1 × V = 11.1 × 0.0821 × 290
V = 264.28 L
Thus, 264.28 L of CO₂ would be produced each day.
The volume of [tex]\rm CO_2[/tex] produced has been 264.28 L.
The volume of the carbon dioxide gas produced can be calculated with the ideal gas equation.
The moles of [tex]\rm NO_3^-[/tex] has been:
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of 275 g [tex]\rm NO_3^-[/tex] has been:
Moles = [tex]\rm \dfrac{275}{62}[/tex]
Moles of [tex]\rm NO_3^-[/tex] = 4.44 moles
The balanced equation gives that with the reaction of 2 moles [tex]\rm NO_3^-[/tex] , 5 moles carbon dioxide has been formed.
Moles of carbon dioxide formed with 4.44 mol [tex]\rm NO_3^-[/tex] has been:
2 moles [tex]\rm NO_3^-[/tex] = 5 moles [tex]\rm CO_2[/tex]
4.44 moles [tex]\rm NO_3^-[/tex] = 11.1 moles [tex]\rm CO_2[/tex].
The volume of the [tex]\rm CO_2[/tex] can be calculated as:
Pressure [tex]\times[/tex] Volume = moles [tex]\times[/tex] Rydberg constant [tex]\times[/tex] temperature
For the [tex]\rm CO_2[/tex] produced:
1 atm [tex]\times[/tex] Volume = 11.1 mol [tex]\times[/tex] 0.0821 atm.L/K.mol [tex]\times[/tex] 290 K
Volume = 264.28 L.
The volume of [tex]\rm CO_2[/tex] produced has been 264.28 L.
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the value of ΔE for a system that performs 13KJ of work on its surroundings and loses 9KJ of heat is ??
Answer:
ΔE = -22 KJ
Explanation:
Given data:
Work done = 13 KJ
Heat lose = 9 KJ (exothermic process)
ΔE = ?
Solution:
Formula:
ΔE = q + w
ΔE = - 9KJ + (-13 KJ) (work is done by the system on surrounding that's why we add negative sign)
ΔE = -22 KJ
i need help with this
Answer:
2nd one
Explanation:
Explain viscosity
Pls help ty