elements was not easily spotted by ancient cultures?

Answers

Answer 1

Answer:

Bromine (Br)

Explanation:

Im assuming thats the answer you are looking for since you didnt include any options :,)


Related Questions

A solution has a [OH-] of 1 x 10^-12 M. What is the [H3O+] of the solution?

Answers

First, lets find the pOH
pOH=-log[OH] ----> pOH=-log[1x10^-12] ----->pOH=12
Now we can find the pH
14-12=2
Now we can use the pH=-log[H3O] to find the hydrogen ion concentration
2=-log[H3O] ------>[H3O]=1.0 x 10^-2

2. Which of the following elements does not lose an electron easily? (a) Na (6) F (c) Mg (d) Al​

Answers

Answer:

Answer: (b) F

Explanation:

Sodium has 1, magnesium has 2 and Aluminium has 3 electrons in its outermost shell whereas Fluorine has 7 electrons in its outermost shell hence Fluorine does not lose electrons easily.

The electronic configuration of fluorine is 2,7.

Fluorine is the ninth element with a total of 9 electrons.

The first two electrons will go in the 1s orbital.

The next 2 electrons for F go in the 2s orbital.

The remaining five electrons will go in the 2p orbital. Therefore the F electron configuration will be 1s22s22p5.

What do the craters on the moon’s surface tell us about its past?

There may be alien life on the moon.

The moon’s surface has been struck with other objects.

There are volcanoes on the moon.

Mountains formed on the moon.

Answers

Answer:

The moon's surface has been struck with other objects.

Explanation:

Answer 1 - Craters are not a sign of alien life as there is nothing directly showing the crater's are not natural phenomena.

Answer 2 - Craters are (normally) produced by the impact force of a foreign object that is moving quickly and collides with an object of larger size.

Answer 3 - Volcanos form mountains and magma tubes, not craters.

Answer 4 - The formation of mountains does not relate to craters in any meaningful way.

Answer: The moon’s surface has been struck with other objects.

Explanation: because those crates were caused by drifting objects such as asteroid's and meteorite's that caused craters in the moon.

the answer is D

present the cell in which the following reaction place

Mg(s) + 2Ag+ (0.0001 M) ----> Mg2+ (0.130M) + 2Ag(s)

calculate its E if E∅ is 3.17 V​

Answers

[tex]\Huge{\green}\fcolorbox{blue}{cyan}{\bf{\underline{\red{\color{red}Answer}}}}[/tex]

2.96V

Explanation:

[tex] \sf Mg(s) + 2 {Ag}^{ + } (0.0001M) \longrightarrow {Mg}^{2 + } (0.130M) + 2Ag(s) \\ \\ \sf E{ \degree} = 3.17V[/tex]

As per the Nerest equation

[tex] \sf E_{cell} = E_{cell}{ \degree} - \frac{2.303RT}{nF} log \frac{ [M]}{ [{M}^{n + }] } \\ \\ \sf E_{cell} = E_{cell}{ \degree} - \frac{0.0592}{n} log \frac{[M]}{[ {M}^{n + } ]} [/tex]

Here n = 2

at the n depicts the number of electrons

M = Mg as it is neutral after the product

while M+ = Ag2+ as it is positively charge after the product

[tex] \implies \sf E =3.17 - \frac{0.0592}{2} log \frac{[Mg]}{ {[{Ag}^{ + }]}^{2} } \\ \\ \sf \implies E = 3.17 - 0.0292 log[ \frac{0.130}{ {10}^{ - 8} } ] \\ \\ \sf \implies E = 3.17 - 0.0292 log[130 \times {10}^{5} ] \\ \\ \sf \implies E = 3.17 - 0.0292 \times 7.11 \\ \\ \sf \implies E = 3.17 - 0.2076 \\ \\ \sf \boxed {\pink \implies \pink{E = 2.96V}}[/tex]

name two regulations that mining operations must follow to reduce the impact they have on the environment?

Answers

Answer:

The Clean Water Act and the Endangered Species Act.

Explanation:

mining operations must follow these regulations or else they will not be able to use the land

Find the number of CoCl2 units present in a 0.78 mol sample.

Answers

[tex]\qquad\qquad\huge\underline{{\sf Answer}}[/tex]

Here we go ~

1 mole of [tex] \sf{ COCl_2} [/tex] has 6.022 × 10²³ molecules of the given compound.

So, 0.78 mole of [tex] \sf{COCl_2} [/tex] will have ~

[tex]\qquad \sf  \dashrightarrow \: 0.78 \times 6.022 \times 10 {}^{23} [/tex]

[tex]\qquad \sf  \dashrightarrow \: \approx4.7 \times 10 {}^{23} \: \: \: molecules[/tex]

How does the rate of formation of o2 compared with the rate of formation of h2o and the rate of hydrogen peroxide consumption

Answers

The rate of formation of water and the decomposition of hydrogen peroxide is double as compared to rate of formation of oxygen.

What is chemical reaction?

The chemical reaction is given as the reaction of the reactants in the process to form the new compound.

The chemical reaction with the decomposition of hydrogen peroxide is:

[tex]\rm 2\;H_2O_2\;\rightarrow 2\;H_2O\;+\;O_2[/tex]

The rate of formation of water is given to be double the rate of formation of oxygen as 2 moles of water formed with 1 mole of oxygen.

The rate of disappearance of hydrogen peroxide is double with formation of oxygen as for decomposition of 2 moles of hydrogen peroxide, 1 mole of oxygen is formed.

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20. What is the name of the compound?
0 3,1 diethylcyclopentane
O 1, 3 dimethylcyclopentane
0 1,3 diethylcyclopentane
O 3,1 dimethylcyclopentane

Answers

Answer:

There is no compund in the question...could you provide it please?

(C=12.01 amu, H=1.008 amu, O=16.00 amu)
[?] g/mol CH20

Answers

CH₂O = C + 2.H + O

= 12.01 + 2 x 1.008 + 16

= 30.026 amu = 30.026 g/mol

what is the balanced equation for the production of water?

Answers

Answer:

H₂ + O₂ → H₂O

Now, check that oxygen has two atoms on the left and one on the right

so, you put 2 on the right side

H₂ + O₂ → 2H₂O

oxygen is balanced so, add 2 on H₂ to balance out hydrogen

THE FINAL BALANCED EQUATION:

2H₂ + O₂ → 2H₂O

Question: What is the specific heat of iron if 985 J of energy is required to raise the temperature of 158.5 g from 10.0°C to 24.0°C?

I will give brainliest please help​

Answers

Answer: 0.065

Explanation:

Helppppppppppppppppp

Answers

Answer:

I think it's B

Explanation:

Brainlest po

Maybe i been learn this before

Vote Bbm and sara on election for the win.

The correct answer is E.

A radioactive nuclide that is used for geological dating has an atomic number of 19 and mass number 40. which is the symbol of this nuclide? superscript 19 subscript 21 upper k. superscript 21 subscript 19 upper k. superscript 40 subscript 19 upper k. superscript 19 subscript 40 upper k.

Answers

The symbol of the radioactive nuclide given the data is superscript 40 subscript 19 upper K (⁴⁰₁₉K)

Composition of atoms

An atom is composed of sub-particles which include

Proton Neutron Electron

How to represent an atom

The symbol of an atom showing its atomic number and molar mass can be represented as follow

ⁿₓA

Where

n is the mass number x is the atomic number A is the symbol

How to represent the symbol of the nuclei Mass number (n) = 40Atomic number (x) = 19Symbol (A) = K Representation =.?

ⁿₓA => ⁴⁰₁₉K

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Answer:

c

Explanation:

edge

Lake Michigan holds 1.3 x 1015 gallons of water. If just Chicago removed water from the
lake and it never rained again, how many days would the water last? Chicago uses 1.2 x 109
gallons of water /day
1,300,000,000,000,000 gallons
Show work

Answers

1.3 x 10¹⁵ : 1.2 x 10⁹ = 1.083 x 10⁶

Answer:

1.3x 10 15 gallons of water / 1.2x 10 9 gallons/day=

1.1x 10 6 gallons/day

Explanation:

A 1. 0 l solution of agno3 and pb(no3)2 has a ag concentration of 0. 20

Answers

With an Ag concentration of 0.020 M and a Pb2+ concentration of 0.0010 M, Only PbSO₄(s) will precipitate. The correct option is C.

What is molarity?

Molarity is the measure of the concentration of any solute in per unit volume of the solution.

The equations are

[tex]\rm Ag_2SO_4--- > 2Ag++SO4^{-2}[/tex]

[tex]PbSO_4--- > Pb_2+ +SO4^{-2}[/tex]

Therefore:

[tex]Ag_2SO_4=[0.02^2[0.001]]\\Ag_2SO_4=4 \times 10^{-7}[/tex]

and

[tex]PbSO_4=[0.001^2[0.001]]\\PbSO_4=4*10^{-6}[/tex]

Since, [tex]PbSO_4 > > PAg_2SO_4[/tex], only  PbSO₄ will precipitate.

Thus, the correct option is (C) Only PbSO₄(s) will precipitate.

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When butane burns in an excess of oxygen, the principal products are:.

Answers

Answer:

Carbon dioxide and water

Explanation:

All hydrocarbons, when burned in excess of oxygen produces carbon dioxide and water [along with the unused oxygen].

The equation for the combustion of butane is:

C₄H₁₀ + 6.5O₂ → 4CO₂ + 5H₂O

19. A precipitate is expected when an aqueous solution of potassium iodide is added to an aqueous solution of a. Calcium nitrat

Answers

The reaction of potassium iodide with silver nitrate results in the formation of silver iodide as a precipitate.

What is a precipitate?

A precipitate is given as the solid deposition in the solution. It is formed as the product in the chemical reaction with the insolubility in the solution.

The reaction of KI with silver nitrate results in the formation of soluble potassium nitrate and insoluble silver iodide, which forms as the precipitate.

Thus, the reaction of potassium iodide with silver nitrate results in the formation of silver iodide as a precipitate.

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If a rock sample originally contained 12 g of uranium 235, how much will be left after 2 half lives?

Answers

Answer:

3 g

Explanation:

new mass = (1/2)^n * original mass

where n = number of half lives

(1/2) ^2 * 12

= 3 g

Help with chem

please write the formula for
nickel(IV) sulfite.

Answers

the formula is NiSO3?

Please help
a solution of potassium hydroxide (koh) was titrated against a solution of hydrochloric acid. how
many moles of potassium hydroxide would react with 1 mole of hydrochloric acid? (hint: it may help
to write out a balanced symbol equation for the reaction.)

Answers

The number of moles of potassium hydroxide that would react with 1 mole of hydrochloric acid will be 1.

Stoichiometric Ratio

From the balanced equation of the reaction as shown below:

[tex]KOH + HCl --- > KCl + H_2O[/tex]

One would see that the stoichiometric mole ratio of [tex]KOH[/tex] to that of [tex]HCl[/tex] is 1:1.

This means that 1 mole of KOH will require 1 mole of HCl for a complete reaction that obeys the law of conservation.

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100 POINTS!!!
What coefficient must I add to the product to balance the following equation?
La2O3 + 3H2O --> La(OH)3

A: 2
B: 3
C: 1
D: it is balanced as it

Answers

The answer would be b.3 i’m pretty sure

Coefficient A: 2 must be added to the product to balance the equation.

What is a chemical equation?a chemical equation is a representation of elements taking part in chemical reactions.in a chemical reaction, all elements are written with their physical state.Law of a chemical equation

 The mass of the reactant side is always equal to the mass of the reactant side.

To balance the chemical equation coefficient is added to make the number of atoms equal on both sides.

                La₂O₃+ 3H₂O => 2La(OH)₃

Left-hand side of atoms is equal to right-hand side La=2            

                                                                                     O=6

                                                                                     H =6

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What is the mass percent when 96 grams of NaCl is dissolved in 255 grams of water

Answers

This would mean the masses of Na and Cl are 22.99g and 35.45g respectively. Therefore, the percent composition of NaCl is 39.3% sodium and 60.7% chloride.

A student heated some copper(II) carbonate using this apparatus:
metal
carbonate
limewater
HEAT
(a) Describe and explain what would happen to the limewater (2)
(b) Write a balanced chemical equation, including state symbols,
for the reaction that occurs when copper (II) carbonate is
heated.

Answers

Answer:

Below.

Explanation:

a) When limewater is heated it gives off carbon dioxide gas and leaves calcium oxide( CaO).

CaCO3 ----> CaO + CO2

b) When copper II carbonate is heated the equation is:

CuCO3 --->  CuO + CO2.

which sequence represents increasing levels of organization in the human body

Answers

Answer:

It is convenient to consider the structures of the body in terms of fundamental levels of organization that increase in complexity: subatomic particles, atoms, molecules, organelles, cells, tissues, organs, organ systems, organisms and biosphere

Explanation:

i hope it help you

How is star stuff connected to the sun?

Answers

The sun is a type of big star.

how is the water in the swimming pool similar to earth's interior? How is it different?

Answers

Explanation:

Water is a liquid, it is same as the oceans water, but, swimming pool water contains Flourine (F) or Chlorine (CI) to clean it up, scinece there is no way that the water moves.

Which factor helped to first drive plants to live on land?
greater access to sunlight on land
lack of competition in the water
greater access to water on land
lack of turgor pressure in the water

Answers

A factor which helped to first drive plants to live on land is: A. greater access to sunlight on land.

The chemical reaction for photosynthesis.

In Science, photosynthesis is a light-dependent process and it is typically represented by the following chemical reaction:

Carbon dioxide + water + light energy ⇒ sugar + oxygen

Based on the chemical reaction above, we can infer and logically deduce that light energy (sunlight) obtained from the Sun is a very important factor for photosynthesis.

Consequently, greater access to sunlight on land became a factor which helped to first drive plants to live on land.

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Answer:

it is A step by step

Explanation:

For which part of the engineering process would the use of statistics to
analyze data about a new drug test be helpful?
O A. Making a plan
a
B. Identifying a need
O C. Testing the solution
D. Evaluating the results

Answers

Answer:

D

Explanation:

While evaluating you will notice if it works or not

Describe each type of reaction that can take place and explain the factors that affect reaction rates.

There are 2 different questions above...

Answers

Answer(s):

synthesis, decomposition, combustion, single replacement, and double replacement.the physical state of the reactants, and surface area, temperature, and the presence of a catalyst are the four main factors that affect reaction rate.

::: (\_(\ Hope

*: (=' :') this

•.. (,('')('') helped :)

Use the following equation to answer questions : 2 C6H10 + 17 O2 12 CO2 + 10 H2O a) If I do this reaction with 35 grams of C6H10 and 45 grams of oxygen, how many grams of carbon dioxide will be formed? b) What is the limiting reagent? ___________ c) How much of the excess reagent is left over after the reaction is finished? d) If 35 grams of carbon dioxide are actually formed from the reaction, what is the percent yield of this reaction?

Answers

The answers of every subquestion is given below:

What is percentage yield ?

Percent yield of the reaction is the percent ratio of actual yield to the theoretical yield.It is calculated to be the experimental yield divided by theoretical yield multiplied by 100%.

The theoretical yield is the amount predicted by a stiochiometric calculation based on the number of moles of all reactants present.

This calculation assumes that only one reaction occurs and that the limiting reactant reacts completely.

The actual yield is the quantity of a product that is obtained from a chemical reaction.

          2 C₆H₁₀ + 17 O₂ ⇒ 12 CO₂ + 10 H₂O

1. When you do this calculation for 35 grams of C₆H₁₀, you find that 113 grams of CO2 will be formed.

When you do the calculation for 45 grams of oxygen,You find that 43.7 grams of CO2 will be formed.Because 43.7 grams is the smaller number forming 43.7 grams of product.

2. Oxygen is the limiting reagent

3. 21.4 grams of C₆H₁₀ will be left over.

4.  80.1%

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