The Chinese first began recording astronomical observations about 2,000 years ago.


True
False

Answers

Answer 1
The answer is false

Related Questions

What is the volume, in liters, of a 0.2 M solution containing 8.5 grams of AgNO3?

Answers

Answer:

The volume of a 0.2 M solution containing 8.5 grams of AgNO₃ is 0.25 L

Explanation:

 Molarity (M) is a common way of expressing the concentration of solutions. It is defined as the number of moles of solute per volume of solution. The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution.

[tex]Molarity=\frac{number of moles of solute}{volume}[/tex]

Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].

Being the molar mass of AgNO3 169.87 g / mol, then you can apply the following rule of three: if 169.87 grams are present in 1 mole of the compound, 8.5 grams will be present in how many moles?

[tex]amount of moles=\frac{8.5 grams*1 mole}{169.87 grams}[/tex]

amount of moles= 0.05

So, being the molarity equal to 0.2 M, replacing in the definition of molarity:

[tex]0.2 M=\frac{0.05 moles}{volume}[/tex]

and solving you get:

[tex]volume=\frac{0.05 moles}{0.2 M}[/tex]

volume=0.25 L

The volume of a 0.2 M solution containing 8.5 grams of AgNO₃ is 0.25 L

1. Why does light bend when it changes medium?​

Answers

Answer:

The bending of light as it passes from one medium to another is called refraction

Explanation:

How many moles are there in 200 grams of carbon dioxide Please show work

Answers

n = m/M
= 200g/(12.01g/mol + 2(16.00g/mol))
=4.54mol

According to the mole concept, there are 4.54 moles present in 200 grams of carbon dioxide.

What is a mole?

Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.

It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.

It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass  in grams present in one mole  of atoms is its atomic mass.Number of mole= mass /molar mass which is 200/44=4.54 moles

Learn more about moles,here:

https://brainly.com/question/26416088

#SPJ2

The weather is warm and dry
Which change would bring a cold front in

A.several days of gray skies

A.dry air and sunny skies

B.rain or thunderstorms

C.extended period of rain or snow

Answers

because im  d and god is go od and 9 x 10 is 99999because    im god and god is good a   nd 9 x 10 i d and god is goo   d and 9 x 10 is 99999because im god and god is good a  nd 9 x 10 is 99999because im god and god is good and 9 x 10 is 99999

Answer:the answer is c

Explanation:

PLZZZ help asaap plzzz I give brainliest are the following reactions a SYNTHESIS, DECOMPOSITION, COMBUSTION, SINGLE REPLACEMENT or DOUBLE REPLACEMENT reactions?
N2 (g) + 3 H2 (g)→ 2NH3 (l) ______________

2 H2(g) + O2(g--> 2 H2O(g)

Answers

Answer:

Synthesis

Explanation:

Two reactants are becoming one product, so it is a synthesis reaction.

Decomposition is the opposite, so when one molecule becomes simpler atoms.

Example: 2NaCl -> Cl2 + Na

Combustion is reaction with a product of water and carbon dioxide.

Example: CH4 + 2O2 -> CO2 + 2H2O

Single displacement is when one atom takes the place of the other.

Example: K + NaCl -> KCl +Na (where K took the place of Na)

Double displacement is like single displacement but it happens twice. Think of it like the atoms exchanging partners.  

Example: HCl +NaH -> NaCl + HOH

Answer:

(i) N2(g)+3H2(g) -->2NH3(g) - When the equilibrium changes, the concentrations of all substances involved in the equilibrium must also change. For our equilibrium reaction: N2(g) + 3H2(g) ⇔ 2NH3(g) + Heat

(ii) 2 H2(g) + O2(g) --> 2 H2O(g) - Synthesis Reaction

HENCE BOTH THE REACTIONS COULD BE CLASSIFIED AS SYNTHEYIC REACTION

PLEASE DO MARK MY ANSWER AS THE BRAINLIEST..

<HOPE IT HELPS>

52
p3
N?
Br1
CaBr2
Cas
Ca3P2
Cal2
Ca3N2
Cat2
K1
Mg2
Zn2
Fe3

Answers

I’m not sure what you are asking sorry.


When investigating a factor that effects the rate of photosynthesis, you needed to keep the
plant at a temperature of 250C. How did you do this?

Answers

Answer:

Photosynthesis defines the process by which plants and some bacteria manufacture glucose. Scientists summarize the process as follows: using sunlight, carbon dioxide + water = glucose + oxygen. The process occurs within special structures called chloroplasts located in the cells of leaves. Optimum photosynthetic rates lead to the removal of greater amounts of carbon dioxide from the local atmosphere, producing greater amounts of glucose. Since glucose levels within plants are difficult to measure, scientists utilize the amount of carbon dioxide assimilation or its release as a means to measure photosynthetic rates. During the night, for example, or when conditions are not prime, plants release carbon dioxide. Maximum photosynthetic rates vary between plant species, but crops such as maize can achieve carbon dioxide assimilation rates as high as 0.075 ounce per cubic foot per hour, or 100 milligrams per decimeter per hour. To achieve optimum growth of some plants, farmers keep them in greenhouses that regulate conditions such as humidity and temperature. There are three temperature regimes over which the rate of photosynthesis changes.

Low Temperature

Enzymes are protein molecules used by living organisms to carry out biochemical reactions. The proteins are folded into a very particular shape, and this allows them to bind efficiently to the molecules of interest. At low temperatures, between 32 and 50 degrees Fahrenheit – 0 and 10 degrees Celsius – the enzymes that carry out photosynthesis do not work efficiently, and this decreases the photosynthetic rate. This leads to a decrease in glucose production and will result in stunted growth. For plants inside a greenhouse, the installation of a greenhouse heater and thermostat prevents this from occurring.

Explanation:

Gaseous butane CH3CH22CH3 will react with gaseous oxygen O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. Suppose 0.58 g of butane is mixed with 0.874 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 3 significant digits.

Answers

Answer:

0.378 g of H₂₂O can be produced.

Explanation:

The combustion reaction is:

2CH₃(CH₂)₂CH₃  +  13O₂  →  8CO₂  +  10H₂O

We convert the mass of reactants to moles:

0.58 g . 1mol / 58.1g = 0.00998 moles of butane

0.874 g . 1mol / 32g = 0.0273 moles of O₂

Oxygen is the limiting reactant. Look at stoichiometry.

2 moles of butane need 13 moles of oxygen to react

Then, 0.00998 moles of gas may react to (0.00998 . 13) / 2 = 0.06487 moles of oyxgen. I only have 0.0273 moles, so i do not have enough oxygen to complete the reaction.

Let's find out the product.

13 moles of oyxgen can produce 10 moles of water.

Then 0.0273 moles of O₂ may produce (0.0273 . 10)/13 =  0.021 moles

We convert to mass  →  0.021 mol . 18g /1mol = 0.378 g

What happens when a new star contracts?

Answers

Answer:

The outer shell of the new star will start to expand.

Explanation:

The new star will continue to glow for millions or even billions of years. As it glows, hydrogen is converted into helium in the core by nuclear fusion. The core starts to become unstable and it starts to contract. The outer shell of the star, which is still mostly hydrogen, starts to expand.

Explanation provided by:

StarChild: Stars - NASA

PLEASE HELP this is physical science.

Answers

Bone age : 22,920 years

Further explanation

Given

Nt = 2.5 g C-14

No = 40 g

half-life = 5730 years

Required

time of decay

Solution

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

t = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

Input the value :

[tex]\tt 2.5=40.\dfrac{1}{2}^{t/5730}\\\\\dfrac{2.5}{40}=\dfrac{1}{2}^{t/5730}\\\\(\dfrac{1}{2})^4=\dfrac{1}{2}^{t/5730}\\\\4=t/5730\rightarrow t=22920~years[/tex]

If H3O+ is an acid according to Brønsted-Lowry, what is its conjugate base?
Select one:
Need ASAP please
a. H4O2+(aq)
b. H+(aq)
c. H2O(aq)
d. OH-(aq)

Answers

Answer:

C. H20(aq)

Explanation:

How many elements are present in the compound RbMnO4?

Answers

3 elements

Rubidium
Manganese
Oxygen

Hope this helped☺️

what happens when hydrogen gas is passed over hot ferric oxide​

Answers

Answer:

When hydrogen is passed over hot ferric oxide (FeO) hydrogen reacts with oxygen present in the compound and forms water (H2O) and pure Iron

Explanation:

Answer:When hydrogen gas is passed over hot copper oxide, the black coating on the surface turns brown as the reverse reaction takes place and copper is obtained.

Explanation:

How are the cells made by meiosis different from the original parent cell that
produced them?

Answers

Mitosis creates two identical daughter cells that each contain the same number of chromosomes as their parent cell. In contrast, meiosis gives rise to four unique daughter cells, each of which has half the number of chromosomes as the parent cell.

What is the result of 2.58×0.12, including correct significant figures? Select the correct answer below: 0.3096 0.31 0.310 0.3

Answers

Answer:

The answer would depend on the required significant number.

Explanation:

0.3096 is the complete answer

0.31 is the answer when the hundredths place is asked

Consider a reaction that connects the ends of a chain of carbons to form a ring. The closure of the ring results in the formation of a new chemical bond, with the bonding electrons going into a bonding sigma molecular orbital at a lower energy. Which of the following statements correctly describes the resulting enthalpy, entropy, and heat changes? Mark all that are correct.
A. The entropy of the surroundings decreases (AS surr < 0) because the closure of the ring results in fewer conformations for the system.
B. The system releases energy to the environment, because its internal energy decreases.
C. The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.
D. The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.
E. The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.

Answers

Answer:

The system releases energy to the environment, because its internal energy decreases.

The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.

The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.

The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.

Explanation:

Now we know that when a reaction is exothermic heat is given off. In this case, we have a reaction that connects the ends of a chain of carbons to form a ring.  The bonding electrons now move into a lower energy bonding sigma molecular orbital.

This leads to a decrease in the entropy and enthalpy of the system because energy is given off, the closure of the ring reduces the number of conformations the ring can adopt and  the electrons that form the bond enter an orbital that is at a lower energy.

The entropy of the surroundings is increased as energy is given out. The surroundings absorb heat released by the reaction, and become more disordered.

What can you infer about the growth of the seed type pictured in the graphs below? ( Note, the vertical axis represents the number of seeds )
The graph shows Time in days from 0 to 5 on the x-axis and 0 to 100 on the y-axis with 5 percent light. Day 0 there are 100 seeds and 0 sprouts. The number of seeds and sprouts remains the same through 2.5 days. Then the number of seeds decreases while the number of sprouts increases. Day 5 there are 30 seeds and 70 sprouts.The graph shows Time in days from 0 to 5 on the x-axis and 0 to 100 on the y-axis with 80 percent light. Day 0 there are 100 seeds and 0 sprouts. The number of seeds and sprouts remains the same through 2.5 days. Then the number of seeds decreases while the number of sprouts increases. Day 5 there are 30 seeds and 70 sprouts.
a.
More seeds grow with more light.
b.
More seeds grow with less light.
c.
The seeds grow faster with more light.
d.
Light has no effect on seed growth.

Answers

Answer:

D

Explanation:

I just did it on Edge

Answer:It’s D

Explanation: It was in my test

Calculate the number of moles 2.5 g of calcium hydroxide.

Answers

Answer:

0.044 mol CaOH

General Formulas and Concepts:

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to Right

Chemistry

Atomic Structure

Reading a Periodic TableWriting Compounds

Stoichiometry

Using Dimensional AnalysisExplanation:

Step 1: Define

2.5 g CaOH

Step 2: Identify Conversions

[PT] Molar Mass of Ca - 40.08 g/mol

[PT] Molar Mass of O - 16.00 g/mol

[PT] Molar Mass of H - 1.01 g/mol

Molar Mass of CaOH - 40.08 + 16.00 + 1.01 = 57.09 g/mol

Step 3: Convert

[DA] Set up:                                                                                                     [tex]\displaystyle 2.5 \ g \ CaOH(\frac{1 \ mol \ CaOH}{57.09 \ g \ CaOH})[/tex][DA] Multiply/Divide [Cancel out units]:                                                         [tex]\displaystyle 0.043791 \ mol \ CaOH[/tex]

Step 4: Check

Follow sig fig rules and round. We are given 2 sig figs.

0.043791 mol CaOH ≈ 0.044 mol CaOH

Calculate what will be the volume of 10.0 grams of
gaseous ammonia at STP?

Answers

Answer:

13.22 L

Explanation:

Given data:

Volume of ammonia = ?

Mass of ammonia = 10.0 g

Temperature = standard = 273.15 K

Pressure = standard = standard = 1 atm

Solution:

First of all we will calculate the number of moles of ammonia.

Number of moles = mass/molar mass

Number of moles = 10.0 g/ 17 g/mol

Number of moles = 0.59 mol

one mole of any substance at standard temperature and pressure occupy 22.41 L . Thus, 0.59 moles of ammonia will occupy,

0.59 mol × 22.4 L / 1 mol

13.22 L

Answer: 12.4L

Explanation:

mw NH3 18

1 mole = 22.4L

10g = 10/18 moles

Which bond would require more energy to break apart? (Short bond or Long bond). Explain
a) longer bond. because the charges are further apart
b) shorter bond. because the charges are closer together
c) shorter bond. because the charges are both positive
d) longer bond. because the charges are closer together

Answers

Answer:

shorter bond, because charges are close apart

Explanation:

shorter the bond length more is the energy required to break the bond for example if you take three pencils of different sizes one longer One medium sized One Shot sized if you try to break them the longer pencil will break much faster than the other two because the greater the length the lesser the strength the lesser energy you need to apply to break them apart ...

hope you understand

If you were to burn a candle inside of a closed jar and the mass of the
closed jar and candle was 50 grams to begin with, what would the mass of
the jar and smoke be after the candle is done burning?

Answers

Answer:

50g

Explanation:

At the end of the burning process, the mass of the jar and smoke should be 50g after the candle burning is done.

In most systems, the law of conservation of matter finds expression. According to this law "matter is neither created nor destroyed but atoms are rearranged".

In this kind of system, no matter is allowed to escaped and the starting mass of the reactants compared to that of the product will be the same.

The increase in electro negativity when moving left to right on the periodic table can be explained by what?

Answers

Answer: Decrease in size

Explanation:

Electronegativity is defined as the property of an element to attract a shared pair of electron towards itself.

On moving across a period from left to right,   the size of an atom decreases because the electrons get added to the same shell and the nuclear charge keeps on increasing. Thus the electrons get more tightly held by the nucleus.

As, the size of an element decreases, the valence electrons come near to the nucleus. So, the attraction between the nucleus and the shared pair of electrons increases. Thus electronegativity increases.


Determine the the nuclei indicated in blanks in the
right side when Radium (Ra-226) undergoes an
alpha decay
Ne
226/ 88
Ra -->
+

Answers

The daughter isotope  : Radon-222 (Rn-222).

Further explanation

Given

Radium (Ra-226) undergoes an  alpha decay

Required

The daughter nuclide

Solution

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,  

alpha α particles ₂He⁴ beta β ₋₁e⁰ particles gamma particles ₀γ⁰ positron particles ₁e⁰ neutron ₀n¹

The decay reaction uses the principle: the sum of the atomic number and mass number before and after decay are the same

Radium (Ra-226) : ₈₈²²⁶Ra

Alpha particles : ₂⁴He

So Radon-226 emits alpha α particles ₂He⁴  , so the atomic number decreases by 2, mass number decreases by 4

The reaction :

₈₈²²⁶Ra ⇒ ₂⁴He + ₈₆²²²Rn

THE ANSWER IS
Magnesium hydroxide (Mg(OH)2): 58.33

Iron(III) oxide (Fe2O3): 159.70

Answers

Answer:

Ok, thanks?

Have a good day

Thanks for the answer ^^...yes i only commented for the points

You are working to earn enough money for a vacation which costs 2100. Your take-home pay is $16.50/hour, but you only work 4-hour shifts each day. How many days will it take for you to earn enough money to pay for your vacation if all the money you earn goes towards your vacation?

Answers

Answer:

32 days.

Explanation:

First we determine how much is made in a day.

16.50 x 4 = 66.

Next, we divide 2100 by 66 to reach our amount of days needed.

2100 / 66 = 31.818181... [81 is what repeats over and over.]

We round this up to the nearest whole number. You can't underpay, so you have to round.

The next whole number would be 32, so our answer is 32 days.

Examine the diagram of the cell cycle. Which label identifies the stage in which the DNA is copied and the cell grows? W X Y Z

Answers

Explanation:

w is the stage in which dna is copied and cell grows.

Answer:

w

Explanation:

The acid digestion test left 2.595 g of fiber from a composite specimen weighing 3.697 g. The composite specimen weighs 1.636 g in water. If the specific gravity of the fiber and matrix is 2.5 and 1.2, respectively, find the 1. Theoretical volume fraction of fiber and matrix 2. Theoretical density of composite

Answers

Answer:

0.4323 ; 1.5394

Explanation:

Given that :

Specific gravity of Fibre (Sf) = 2.5

Specific gravity of Matrix (Sm) = 1.2

Mass of Fibre, Mf = 2.595g

Weight of composite specimen in water , Wc = 1.636g

Composite weight, Ww = 3.697 g

Weight of Fibre and matrix

Volume fraction of Fibre and matrix :

[(Mf/Sf) ÷ (Mf/Sf + Wc/Sm)] * 100

[(2.595/2.5) ÷ (2.595/2.5 + 1.636/1.2)]

(1.038 ÷ 2.4013333)

= 0.43225986

= 0.4323

2.)

Theoretical density of composite :

Weight of composite / (Mf/Sf + Wc/Sm)

3.697 / (2.595/2.5 + 1.636/1.2)

3.697 / 2.4013333

= 1.5395613

= 1.5394

The French Le Surete included an ex-criminal, Vidocq, who put together files describing the individual modus operendi, or the _____, of each criminal.


criminal behaviors

fingerprints

home addresses

relatives who were also criminals

Answers

Answer:criminal behavior

Explanation:

Edge 2021

Answer:

Criminal Behavior

Explanation:

explain the difference between aldehyde and ketones​

Answers

Aldehyde starts with a and ketones start with k

Answer:

You will remember that the difference between an aldehyde and a ketone is the presence of a hydrogen atom attached to the carbon-oxygen double bond in the aldehyde. Ketones don't have that hydrogen. ... Aldehydes are easily oxidized by all sorts of different oxidizing agents: ketones are not.

2. What is the final temperature when a 32.0 g piece of diamond at 33.5°C is heated with 360 J of energy?
(Cp = 0.509

Answers

Answer:

55.6 °C

Explanation:

From the question given above, the following data were obtained:

Mass (M) of diamond = 32.0 g

Initial temperature (T₁) = 33.5°C

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Final temperature (T₂) =?

Next, we shall determine the change in temperature. This can be obtained as follow:

The final temperature can be obtained as follow:

Mass (M) of diamond = 32.0 g

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Change in temperature (ΔT ) =?

Q = MCΔT

360 = 32 × 0.509 × ΔT

360 = 16.288 × ΔT

Divide both side by 16.288

ΔT = 360 / 16.288

ΔT = 22.1 °C

Finally, we shall determine the final temperature. This can be obtained as follow:

Initial temperature (T₁) = 33.5°C

Change in temperature (ΔT ) = 22.1 °C

Final temperature (T₂) =?

ΔT = T₂ – T₁

22.1 = T₂ – 33.5

Collect like terms

22.1 + 33.5 = T₂

T₂ = 55.6 °C

Therefore, the final temperature is 55.6 °C.

Other Questions
The ferris wheel with a diameter of 150 feet at the fair is out of control and is moving at 60 degrees per second. How many miles per hour is someone moving as it spins out of control? *There are 5,280 feet in a mile. Evaluate the expression x + 8/27. Evaluate the expression for x=8/9 What type of weather would result from a warm ocean current running alongside your coastline? (hint: the water affects the air through conduction) _____of gas molecules with an object is the cause ofpressure by a gas. Solve the system by substitution.-2y - 10 = x- 10x - y = -14 What is the equation of the line perpendicular to Y= 1/2x +6 that passes through the point (4,1) make d the subject of the formula h= d/3 +2 Evaluate the integral. (Remember to use absolute values where appropriate. Use C for the constant of integration.) cos(x) sin(2x) sin(x) dx is it right to kick someone out just because they are not on the lease and or had been evicted in the past? my step-mom recently passed away then like a week and a half later we get a notice that we are being kicked out. Hurry I am timed Which tiny, round factory puts together protein and is often found in the endoplasmic reticulum?ribosomechromosomeGolgi bodychloroplast True or False: The following sentence is an example of hyperbole Jeremy was our class clown. 'When I moved into a new house a few weeks ago, my books, as was natural, moved with me." In this sentence, an antonym of "natural" would be ______.A) AlarmingB) contemptibleC) improperD) smooth According to cell theory, how is hereditary information transmitted?It is passed from gametes to body cells during fertilization.It is passed from old cells to new cells during cell division. ,It is passed between haploid cells and diploid cells during DNA replication. PLZ HELP FAST 5. Which of the following is important to consider when evaluating an argument in a speech?the speaker's tone of voicethe speaker's purposethe speaker's facial expressionsthe speaker's age Does this table represent a function? Why or why not? A. Yes, because the y-values are positive numbersB. No because each x value is different C. No because none of the y values are the same D. Yes because every x value corresponds to exactly one y value What is Standard English?2. Why do we use Standard English?3. When should you use Standard English? 5) 8 - 3(2b - 7)Need help Find the volume of a triangular prisim with the following dimensions.Base= 5Height= 3Length= 8 2. Which type of tissue covers the surface of thebody? Find x in the following problems: