2. This chart describes several characteristics of human civilizations.
(6.04)
Characteristics of Human Civilizations
Stable Food Supply
?
Developed Systems of Writing
Which phrase best completes this list?
A. Created militaries
B. Complex social structures
C. Use of fire for protection
D. Declining population

Answers

Answer 1
The answer would be: B

Related Questions

Convert 75k to oC
(I’ll mark you as brainlister)

Answers

Answer:

-198.15 degrees Celsius

Explanation:

To convert to Celsius from Kelvin, subtract 273.15 from your temperature in Kelvin.

75K - 273.14 = 198 degrees C

carbon-dating was performed on an artefact that was found to have 25% of the original carbon-14 remaining in it

Answers

Im doing carbon-dating too its so hard for what btw whats the wuestion? I can help ya

When a substance freezes, _____.


it releases thermal energy

it absorbs thermal energy

it changes from a solid to a liquid

its temperature drops

Answers

Answer:

It's temperature drops, and if releases thermal energy

Answer:

Its temperature drops

Explain the electrolysis of acidified water​

Answers

Answer:

yqaeh

Explanation:

Electrolysis of acidified water

Water is a poor conductor of electricity, but it does contain some hydrogen ions , H +, and hydroxide ions, OH -. These ions are formed when a small proportion of water molecules naturally dissociate . ... H + ions are attracted to the cathode , gain electrons and form hydrogen gas.

Does a reaction occur when aqueous solutions of sodium sulfide and manganese(II) chloride are combined?
Oyes Ono
If a reaction does occur, write the net ionic equation.

Answers

Answer:

Yes, a reaction occurs

Explanation:

net ionic equation

Mn 2+ (aq) + S 2- (aq) --> MnS (s)

A. Reaction can occur

Oo help it’s for a grade

Answers

Answer: D.kinectic energy

Explanation

Can someone help please

Answers

Answer:

fuse

Explanation:

fuses are made by metal alloys , have low melting point

A(n)____ is a ripened ovary

Answers

A(n) fruit is a ripened ovary

Organisms are classified into different kingdoms based on?...

Answers

Answer:

Food and cell type

Explanation:

Kingdoms are by far the most basic legal structure for living objects. Living objects are classified into realms depending on how they consume food, the kinds of cells that produce their bodies, and the total type of tissue in their bodies.

explain what is the difference between bohr and rutherford atomic models

Answers

Answer:

The Rutherford Model shows an atom with electrons orbiting a fixed, positively charged nucleus in set, predictable paths. The Bohr model shows electrons travel in defined circular orbits around the nucleus.

I need help with this question

Answers

what question do you need help with

Answer:

there is no question posted

If magnesium and nickel were used as electrodes to construct an electrochemical cell like the one shown at right, which metal would form the anode and which the cathode?

anode:

cathode:​

Answers

Answer:

anode: magnesium

cathode: nickel

Explanation:

edg. 2021

How many grams of sodium metal must be introduced to water to produce 3.3 grams of hydrogen gas?

Answers

Answer:

The mass of sodium metal that must be introduced to water to produce 3.3 grams of hydrogen gas, H₂, is approximately 18.82 grams of sodium metal

Explanation:

The given mass of hydrogen gas produced = 3.3 grams

The molar mass of hydrogen gas, H₂ = 2.016 g/mol

The number of moles of hydrogen gas in 3.3 grams of H₂, 'n', is given as follows;

n = Mass/(Molar mass)

n = 3.3 g/(2.016 g/mol) = 1.63690476 moles of H₂

The reaction of sodium and water can be written as follows;

2Na + 2H₂O → 2NaOH + H₂ (g)

2 moles of sodium produces 1 mole of hydrogen gas, H₂

Therefore;

1.63690476/2 moles of sodium will produce 1.63690476 moles of hydrogen gas, H₂

The molar mass of sodium, Na ≈ 22.989 g/mol

The mass of 1.63690476/2 moles of sodium, 'm', is given as follows;

m = 1.63690476/2 moles × 22.989 g/mol ≈ 18.8154018 grams ≈ 18.82 grams

The mass of sodium that will produce 3.3 grams of hydrogen, m ≈ 18.82 grams of sodium metal.

Which of the following would be a value measured using a scale in lab?
O Actual yield
O Percent yield
O Theoretical yield
O Molar ratio

Answers

Answer:

A. Actual Yield

Since all of the others are calculated not measured outright.

4A1 + 302 →
2Al2O3. How many grams of oxygen (O2)
are needed to produce 95 grams of
aluminum oxide (Al2O3)?

Answers

Answer: 44.706g Al2O3

Explanation:

4A1 + 302 → 2Al2O3

3×(16×2) 2{(27×2)+(16×3)}

= 96 = 204

So

To produce 204g of Al2O3,We need . 96g of O2

To produce 1g of Al2O3,We need

. (96÷204)= 0.47g of O2

To produce 95g of Al2O3,We need

. (0.47×95)= 44.706g of O2

.

So, 44.706 grams of oxygen (O2)

are needed to produce 95 grams of

aluminum oxide (Al2O3).

How many atoms in 12 moles of Mg?

Answers

I would say it comes to 6mg

heeeeeeeeeeeeeeeeeeeeeeeeeeeeeelp

Answers

I think u chose the right answer

1. How many liters of a 0.50 M solution are needed to give 3.5 moles of solute?

Answers

Answer:

The volume of solution in liters required to make a 0.250 M solution from 3.52 moles of solute is 14.08 liters of solution

Explanation:

The question relates to the definition of the concentration of a solution which is the number of moles per liter (1 liter = 1 dm³) of solution

Therefore we have;

The concentration of the intended solution = 0.250 M

Therefore, the number of moles per liter of the required resolution = 0.250 moles

Therefore, the concentration of the required solution = 0.250 moles/liter

The volume in liters of the required solution that will have 3.52 moles of the solute is given as follows;

The required volume of solution = The number of moles of the solute/(The concentration of the solution)

∴ The required volume of solution = 3.52 moles/(0.250 moles/liter) = 14.08 liters

The required volume of solution to make a 0.250 M solution from 3.52 moles of solute = 14.08 liters.

Therefore the number of liters required to make a 0.250 M solution from 3.52 moles of solute = 14.08 liters.

Chemical equation=CH4 + O2 = CO2 + H2O.
i. identify the products of the chemical reaction.
ii. explain why these are the products based on trends in the periodic table (the number of
valence electrons, electronegativity, etc.).
iii. identify the types of bonds in the reactants and products.
iv. identify the number of each type of bond in the reactants and products.
v. identify the type of reaction

Answers

Answer:

1.The substance(s) to the left of the arrow in a chemical equation are called reactants. A reactant is a substance that is present at the start of a chemical reaction. The substance(s) to the right of the arrow are called products . A product is a substance that is present at the end of a chemical reaction.The combustion of methane or octane is exothermic; it releases energy. CH4 + 2 O2 → CO2 + 2 H2O + energy The energies of the products are lower than the energiies of the reactants.

Explanation:

Question 3
5 pts
The diagram shows a 21.7kg ball located on a shelf 1.6m above the ground. Which best describes the energy
of the ball?
o C. It has mechanical energy in the form of potential energy
O A. Its energy is lost once it falls off the shelf.
O B. Its energy depends upon the speed the ball will travel.
O D. It has mechanical energy in the form of kinetic energy.

Answers

Answer:

c

Explanation:

The ball of 21.7 kg which is located on a shelf 1.6 m above ground is having a mechanical energy in the form of potential energy. Hence, C best describes the energy of the ball.

What is potential  energy ?

Potential energy is the energy stored on it when the object is at rest. Kinetic energy of an object is generated by virtue of its motion. When a body starts moving its potential energy starts converts to kinetic energy.

The sum of kinetic and potential energy of an object is called its mechanical energy. An object has mechanical energy in the form of kinetic energy when it is at rest. When it starts to move its potential energy converts to kinetic energy.

Therefore, the ball of 21.7 kg placed in the shelf of height 1.6 m has a potential energy as long as it stays there on the shelf. Its potential energy = mgh

p = 21.7 kg × 9.8 m/s² × 1.6 m = 340.25 J

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How many grams of water should be added to 4.00 g NaOH to create 2.00% by mass NaOH solution?

Answers

Answer:

196 grams

because ^^^ was wrong and person in comments said it was 196 and it was right

When NaOH of 4.00 g is being added with water, the mass of water required to create 2.00% of NaOH solution by mass is 196 g.

What is mass percent of solute?

It means that the particular amount of solute in terms of percentage is present in the solute.

Given the mass of the solute, NaOH is 4.00g

Suppose the mass of water required to add is x in g.

The mass percent of the solute is

[tex]\dfrac{2}{100} =\dfrac{4.00}{4.00 +x }[/tex]

x =196 g

Therefore, mass of water required to create 2.00% of NaOH solution by mass is 196 g.

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Based on the chemical reaction below, if you produce 109.34 moles of Na, how

many g of Cl2 were produced? 2NaCl (s) -> 2Na(s) + Cl2(g) *

Answers

Answer: 3881 g of [tex]Cl_2[/tex] will be produced along with 109.34 moles of Na

Explanation:

The balanced chemical equation is:

[tex]2NaCl(s)\rightarrow 2Na(s)+Cl_2(g)[/tex]  

According to stoichiometry :

2 moles of [tex]Na[/tex] are produced along with = 1 mole of [tex]Cl_2[/tex]

Thus 109.34 moles of [tex]Na[/tex] will produced along with=[tex]\frac{1}{2}\times 109.34=54.67moles[/tex]  of [tex]Cl_2[/tex]

Mass of [tex]Cl_2=moles\times {\text {Molar mass}}=54.67moles\times 71g/mol=3881g[/tex]

Thus 3881 g of [tex]Cl_2[/tex] will be produced along with 109.34 moles of Na

Excessive use of chemical fertilizer cause chemical pollution.How?

Answers

Explanation:

Chemical fertilizers raise crop yields, but their heavy usage has hardened the soil, diminished fertility, reinforced pesticides, contaminated air and water, and emitted greenhouse gases, posing health and environmental risks.

Which of the following is NOT a common property of water?
o Water has high surface tension.
o Water expands when it freezes.
o Ice is less dense than water.
o Water has low heat of vaporization.

Answers

Answer:

A = water has high surface tension

the answer is a hope this helps and plz give me brainlist :)

CAN SOMEONE HELP ME WITH AS MANY AS POSSIBLE! I WILL GIVE MORE POINTS IF GIVEN ALOT

Answers

Answer:

1.Hydrogen peroxide,2.Potassium nitrate,3.Ethane,4.Ammonium phosphate,5.Aluminium sulfate,6.Barium hydroxide,7.Calcium phosphate,8.Calcium chloride,9.Copper nitrite,10.Iron oxide,11.Sulfuric acid,12.Phosphoric acid,13.Mercury chloride,14.Potassium sulfite,15.Potassium manganate,16.Magnesium acetate,17.Magnesium nitrate,18.Sodium chloride,19.Sodium acetate,20.Ammonium bromide

En condiciones normales 1g de aire ocupa un volumen de 773 mL ¿ qué volumen ocupará la misma masa de aire a 0 ºC y la presión a 93,3 KPa *

Answers

Answer:

El volumen que ocupará la misma masa de aire es 839.49 mL.

Explanation:

Las condiciones normales de presión y temperatura (abreviado CNPT) o presión y temperatura normales (abreviado PTN o TPN), son términos que implican que la temperatura referenciada es de 0ºC (273,15 K) y la presión de 1 atm (definida como 101.325 Pa).

La ley de Boyle dice que “El volumen ocupado por una determinada masa gaseosa a temperatura constante, es inversamente proporcional a la presión”  y se matemáticamente como

Presión*Volumen=constante

o P*V=k

La ley de Charles es una ley que dice que cuando la cantidad de gas y de presión se mantienen constantes, el cociente que existe entre el volumen y la temperatura siempre tendrán el mismo valor:  

[tex]\frac{V}{T} =k[/tex]

La ley de Gay-Lussac​ establece que la presión de un volumen fijo de un gas, es directamente proporcional a su temperatura. Se expresa matemáticamente como:

[tex]\frac{P}{T} =k[/tex]

Combinando estas tres leyes se obtiene:

[tex]\frac{P*V}{T} =k[/tex]

Siendo un estado inicial 1 y un estado final 2, la expresión anterior queda determinada como:

[tex]\frac{P1*V1}{T1} =\frac{P2*V2}{T2}[/tex]

En este caso:

P1=  101325 PaV1= 773 mLT1= 273.15 KP2= 93,3 kPa= 93300 PaV2= ?T2= 0°C= 273.15 K

Reemplazando:

[tex]\frac{101325 Pa*773 mL}{273,15 K} =\frac{93300 Pa*V2}{273.15 K}[/tex]

y resolviendo obtenes:

[tex]V2=\frac{273.15 K}{93300 Pa} *\frac{101325 Pa*773 mL}{273,15 K}[/tex]

V2= 839,49 mL

El volumen que ocupará la misma masa de aire es 839.49 mL.

For which of the reactions listed below will Gibbs free energy always be.
positive?
O A. An exothermic reaction that decreases in entropy
B. An exothermic reaction that increases in entropy
O C. An endothermic reaction that decreases in entropy
D. An endothermic reaction that increases in entropy

Answers

I think the answer is: C. An endothermic reaction that decreases in entropy

An endothermic reaction that decreases in entropy. Hence, option C is correct.

What is entropy?

Entropy is the energy of a system that is unuseful to do work.

For a reaction to be spontaneous, the Gibbs' Free Energy must be negative.

The equation for Gibbs Free energy is given by:

G= H-TS

Where, G = Gibbs free energy

H = Enthalpy of the reaction

T = Temperature of the system

S = Entropy of the system

Sign convention for all the quantities:

For H: It is negative for exothermic reactions and positive for endothermic reactions

For S:  It is positive when there is an increase in entropy and it is negative when there is a decrease in entropy.

If we want G to be negative, the conditions necessary are:

G= (-ve) - (+ve) = -ve

The product of temperature and entropy must be positive and that will be positive when there is increase in entropy at any temperature.

Hence, option C is correct.

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How do I do nunber 8?​

Answers

Answer:

DONT CLICK THAT LINK THAT IS HACK AND VIRUS

Explanation:

how many moles of NaOH are produced from 1.20 moles of Na2O?​

Answers

If we begin the problem with 120. grams of
N
a
2
O
and we are trying to find the mass of
N
a
O
H
that can be produced, this is a gams to grams

g
r
a
m
s

m
o
l
s

m
o
l
s

g
r
a
m
s
120
.
g
N
a
2
O
x
1
m
o
l
N
a
2
O
62
.
g
N
a
2
O
x
2
m
o
l
N
a
O
H
1
m
o
l
N
a
2
O
x
40
.
g
N
a
O
H
1
m
o
l
N
a
O
H
=
the gfm of
N
a
2
O
is (2 x 23 + 1 x 16 = 62)
the gfm of
N
a
O
H
is (1 x 23 + 1 x 16 + 1 x 1 = 40)
The mole ratio from the balanced chemical equation is 2 moles of
N
a
O
H
for every mole mole of
N
a
2
O
.

According to the stoichiometry of the mentioned chemical reaction,2.40 moles of NaOH are produced from 1.20 moles of Na₂O.

What is stoichiometry?

Stoichiometry  is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.

Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.It is used in balancing chemical equations for the law of conservation of mass to be implemented.

According to the reaction, as 1 mole  of sodium oxide produces 2 moles of NaOH , therefore 1.20 moles of sodium oxide will produce 1.20×2/1=2.40 moles of sodium hydroxide.

Thus, 2.40 moles of NaOH are produced from 1.20 moles of Na₂O.

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how minimising the use of cars can help save the ozone layer​

Answers

Answer:

minimizing the use of cars can help save the ozone layer by ​Minimizing the amount of gasoline which damages the ozone layer.

therefore the ozone layer is preserved.

have a nice day.

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