Which term is used to measure a star's brightness?​

Answers

Answer 1

Answer:

Magnitude

Explanation:

Astronomers define star brightness in terms of  magnitude (how bright the star appears from Earth)


Related Questions

help in this please....................​

Answers

c) because rays contain electrons

Help a girl out, please!!!!!

Answers

Answer:

The answer will be Number C that is positively and part of the nucleus

Answer:

Part C best describes a proton, as it is positively charged and part on the nucleus

40.*
Which pair of compounds reacts to form a condensation polymer?
A-
CH3COOH and C2H5NH2
B- HCOOH and HOC2H OH
C-HOC6H12OH and HOOCCH.COOH
D- H2NC3H NH2 and HOCH OH

Answers

Answer:

C-HOC6H12OH and HOOCCH.COOH

hexane-1,6-diol and propane-1,3-dioic acid

Answer these two questions, please.

1.Why the melting point and boiling point of [tex]H_{2} O[/tex] are lower than metals?

2.Why the melting point and boiling point of [tex]H_{2} O[/tex] are comparatively higher than other non-metals?

Answers

Answer:

neom, sodium bicarbonate

Compound A reacts with alcoholic KOH to yield compound B which on ozonolyzises followed by the reaction with Zn/H2O gives methanal and propanal Compound A is

Answers

Answer:

1-chlorobutane

Explanation:

Given that :

-- The compound A is made to react with alcoholic KOH and produce compound B.

-- The compound B on Ozonolysis produces methanol as well as propanol

The compound A should be a haloalkanes as treatment of haloalkanes with the alcoholic KOH, it will give alkene.

[tex]$CH_3CH_2CH_2CH_2Cl+KOH( \text{alcohol}) \rightarrow CH_3CH_2CH=CH_2+KCl+H_2O$[/tex]

So, the compound B should be Butene

Now the ozonolysis of the compound B or butene will give methanol and propanal as shown :

[tex]$CH_3CH_2CH=CH_2 \rightarrow CH_2O+CH_3CH_2CHO$[/tex]

Therefore, the compound A is 1-chlorobutane.

Use the periodic table to determine the amount of copper and aluminum nitrate formed in the reaction.

Type the correct answer in the box. Express your answer to the correct number of significant figures.

In the reaction,
moles of Cu and
moles of Al(NO3)3 are formed.

Answers

Answer:

23, 51

Explanation:

Edmentum/plato

As per the balanced reaction, 2 moles of aluminum metal and 3 moles of copper nitrate gives 2 moles of aluminum nitrate and 3 moles of copper metal.  10 g  of Al and 25g of copper nitrate gives 0.08 moles of aluminum nitrate and 0.13 moles of copper.

What is limiting reactant ?

A limiting reactant is the reacting species which is not sufficient in amount to complete the reaction. Hence, the limiting reactant determines the yield of the reaction.

The given reaction is written as:

[tex]\rm 3Cu(NO_{3})_{2} + 2Al \rightarrow 2 Al(NO_{3})_{3} + 3Cu[/tex]

2 moles of Al and 3 moles of copper nitrate gives 2 moles of aluminum nitrate and 3 moles of Cu.

Molar mass of copper nitrate = 187.5 g/mol

atomic mass of aluminum = 27 g/mol

then, number of moles in 10 g of Al = 10 g/27 g/mol = 0.37 moles.

number of moles in 25 g of copper nitrate = 25 g/187.5 g/mol = 0.13 moles.

0.37 moles of Al needs 0.5 moles of copper nitrate to react with. Hence, copper nitrate is the limiting reactant.

3 moles of copper nitrate gives 2 moles of aluminum nitrate. Then 0.13 moles will give 2/3rd of 0.13 i e., 0.08 moles of aluminum nitrate. Similarly 0.13 moles copper nitrate gives 0.13 moles of copper metal.

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Your question is incomplete. But your complete question probably was:

10 g of aluminum metal reacts with 25 g of copper nitrate. Use the periodic table to determine the amount of copper and aluminum nitrate formed in the reaction.

In the reaction,

moles of Cu and

moles of Al(NO3)3 are formed.

What is the percent composition by mass of nitrogen in the compound NH3 (gram-formula mass - 17 g/mol)?
A.18%
B.25%
С.75%
D.82%

Answers

Answer: d 82%. Your welcome

ch
Heat depends on which factor?
how fast the molecules are vibrating
O how big the molecules are
how close the molecules are together
O none of the above

Answers

Answer:

Hello There!!

Explanation:

I believe the answer is how fast the molecules are vibrating.

hope this helps,have a great day!!

~Pinky~

How many atoms are in 9.8 moles of NaCl?

Answers

Answer:

a lot but im pretty sure if u just take avogadros number and multiply it by 9.8 u get the answer

Explanation:

There are 5.89 × 10²⁴ atoms in 9.8 moles on NaCl. Details about number of atoms can be found below.

How to calculate number of atoms?

The number of atoms of a compound can be calculated by multiplying the number of moles of the substance by Avogadro's number.

no of atoms = no of moles × 6.02 × 10²³

According to this question, there are 9.8 moles of NaCl.

no of atoms = 9.8 × 6.02 × 10²³

no of atoms = 5.896 × 10²⁴

Therefore, there are 5.89 × 10²⁴ atoms in 9.8 moles on NaCl.

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Something that can be broken down by living organisms is
a.
biodegradable.
c.
ecological.
b.
economic.
d.
renewable.


Please select the best answer from the choices provided

A
B
C
D

Answers

The answer is A: biodegradable.

Answer:

hii

needed points

What is the equation for the average?
A. Average = (total number of data values) / (sum of all data values)
B. Average = (sum of target data values) / (sum of all data values)
C. Average = (sum of target data values) / (total number of data values)
D. Average = (sum of all data values)/ (total number of data values)
Dacat Selection

Answers

The equation for the average, also known as the arithmetic mean, is:

D. Average = (sum of all data values) / (total number of data values)

The average is calculated by adding up all the data values and then dividing the sum by the total number of data values. This equation provides a measure of central tendency that represents the typical value or the "average" value of a set of data.

Option A, (total number of data values) / (sum of all data values), does not represent the correct equation for calculating the average. Dividing the total number of data values by the sum of all data values does not yield the average. This equation would result in a value that is not representative of the data set.

Option B, (sum of target data values) / (sum of all data values), is not the correct equation for calculating the average. This equation suggests finding the average of specific "target" data values rather than considering the entire data set.

Option C, (sum of target data values) / (total number of data values), is also not the correct equation for calculating the average. Similar to option B, this equation suggests finding the average of specific "target" data values rather than considering the entire data set.

Therefore, the correct equation for calculating the average is D. Average = (sum of all data values) / (total number of data values). This equation provides the most accurate representation of the average value of a given data set.

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A stream of humid air containing 2.50 mol% H2O(v) and the balance dry air is to be humidified to a water content of 10.0 mole% H20. For this purpose, liquid water is fed through a flowmeter and evaporated into the air stream. The flowmeter reading, R, is 95. The only available calibration data for the flowmeter are two points scribbled on a sheet of paper, indicating that readings R = 15 and R = 50 correspond to flow rates V = 40 m/h and V = 96 m/h, respectively.

Answers

Answer: hello your question has some missing data attached below is the missing data

answer:

i) volumetric flow rate = 168 m^3/h = 5932.86 ft^3/h

ii) n = 582.4 Ib mole/hr

Explanation:

Given that the volumetric flow rate is a Linear function of R

V = ∝R + β

where; R1 = 15 , V1 = 40 m/h , R2 = 50, V2 = 96 m/h  input values into equation above

40 = 15∝ + β ----- ( 1 )

96 = 50∝ + β ----- ( 2 )

resolve equations 1 and 2 simultaneously

56 = 35∝ + 0

∴ ∝ = 56 / 35 = 1.6

back to equation 1:  40 = 15(1.6) + β    ∴ β = 40 - 24 = 16

hence ; V = 1.6(95) + 16 = 168 m^3/h = 5932.86 ft^3/h

lets assume room temperature

density of water = 62.4 Ib/ft^3

molecular weight of water = 18

therefore n = ( 62.4 / 18 ) * 168

                  = 582.4 Ib mole/hr

How much mass does 1 mol of O2 gas have?
O A. 16.00 x 2g
O B. 16.00 x (6.02 x 10^23) g
C. 2 x (6.02 x 10^23) g
D. 16.00 g

Answers

Answer:

Option A.

Explanation:

1 mol of anything contains 6.02×10²³ particles.

We know that 1 mol of oxygen gas contains 2 moles of O.

1 mol of oxygen weighs 16 g/mol, the mass for 1 molecule of O.

By the way, the mass for 1 mol of O₂ may be:

Option A  →  16 g/mol . 2 mol

32 g

Oyxgen is a dyatomic molecule, that's why we have 2 moles of O.

Another example can be:

1 mol of water (H₂O) contains 2 moles of H and 1 mol of O.

Question 14 of 30
Which of the following elements has 1 valence electron?
The Periodic Table
A. Sodium (Na)
B. Chlorine (CI)
C. Calcium (Ca)
D. Helium (He)
SUBMIT

Answers

Answer:

A. Sodium (Na)

Explanation:

The total number of electrons in the outermost principal energy level of an element is called the valence electrons of that element.

Na (11)---→1s2 2s2 2p6 3s1

There 1 electron in the outermost principal energy level of Sodium. So, the number of valence electron of Sodium is 11.

Answer:

Na

Explanation:

I was learning about it recently, that dude's right, it's Sodium

How many grams of Lioh are in 1.7 moles?

Answers

Answer:

40.7g

Explanation:

so mass = moles × mr( 6.94+16+1)

=1.7 × 23.94

= 40.698

so 3 S.F = 40.7 g

hope this helps :)

can someone answer this please

Answers

It is copper because it is the most maleable

Question: (02.01 MC) Which state of matter does this image represent?
O Solid
O Liquid
O Gas
O Plasma​

Answers

1. A liquid

explain: water is a liquid

A pan containing 20.0 grams of water was allowed to cool from a temperature of 95.0 °C. If the amount of heat released is 1,200 joules, what is the approximate final temperature of the water?

Answers

Answer:

80.7 °C

Explanation:

Step 1: Given and required data

Mass of water (m): 20.0 gInitial temperature (T₁): 95.0 °CHeat released (Q): -1,200 J (the negative sign is due to it being released)Specific heat capacity of water (c): 4.184 J/g.°C

Step 2: Calculate the final temperature of the water

We will use the following expression.

Q = c × m × (T₂ - T₁)

T₂ = Q / c × m + T₁

T₂ = -1,200 J / (4.184 J/g.°C) × 20.0 g + 95.0 °C = 80.7 °C

Answer:

81 C

Explanation:

Newton’s Second Law of Motion: The Law of 1. __________(Inertia/Acceleration)

The acceleration of an object is 2. _____________ (directly/inversely)

proportional to the magnitude of the net force acting on it, in the

3. _____________ (same/opposite) direction as the net force, and

4. _____________ (directly/inversely) proportional to the

5. _____________ (mass/weight) of the object.​

Answers

Answer:

acceleration

inversly

opposite

directly

mass

How many moles are equivalent to 365 g of aluminum chloride? Using the dimensions analysis. Show work

Answers

Answer:

≈ 2.74 mol [tex]AlCl_{3}[/tex]

(I rounded to 3 sig figs because the starting amount has 3 sig figs.)

Explanation:

[tex]\frac{365g AlCl_{3}}{1}*\frac{1 mol AlCl_{3}}{133.34g AlCl_{3}} =[/tex] 2.73736313184 mol [tex]AlCl_{3}[/tex] ≈ 2.74 mol [tex]AlCl_{3}[/tex]

Hope this helps!

Calculate the standard enthalpy change for the reaction 2A+B⇌2C+2D Use the following data: Substance ΔH∘f (kJ/mol) A -235 B -413 C 193 D -493

Answers

Answer:

ΔH = 283kJ/mol

Explanation:

Using Hess's law, the ΔH of a reaction is equal to the sum of ΔH° of products times its coefficient subtracting the sum of ΔH° of reactants times its coefficient. Replacing, for the reaction:

ΔH = 2ΔH°C + 2ΔH°D - (2ΔH°A+ΔH°B)

ΔH = 2*193kJ/mol + 2*-493kJ/mol - (2*-235kJ/mol+ (-413kJ/mol)

ΔH = 283kJ/mol

I need chemistry help text me at (951) 897-8325 PLEASE

Answers

Just post the question on here

What is used to describe the conditions of a reaction at equilibrium?
O A. A reaction-rate constant
O B. An activation energy
O C. An ideal gas constant
O D. An equilibrium constant
SUBM

Answers

i think the awnser is D

20. Show a correct numerical setup for calculating the molarity of the KOH * (aq) solution. Then state the calculated value of the molarity .

Answers

Answer:

[tex]M_b = \frac{0.10M * 9.50mL}{3.80mL}[/tex] ---- The setup

[tex]M_b = 0.25M[/tex] --- The molarity of KOH

Explanation:

Given

I will answer the question with the attached titration data

Required

The set and the value of the molarity of KOH

First, calculate the volume of acid (HCL) used:

[tex]V_a = Final\ Reading - Initial\ Reading[/tex]

[tex]V_a = 25.00mL - 15.50mL[/tex]

[tex]V_a = 9.50mL[/tex]

Calculate the final volume of base (KOH) used:

[tex]V_b = Final\ Reading - Initial\ Reading[/tex]

[tex]V_b = 8.80mL - 5.00mL[/tex]

[tex]V_b = 3.80mL[/tex]

The numerical setup is calculated using::

[tex]M_a * V_a = M_b * V_b[/tex]

Where

[tex]V_a = 9.50mL[/tex]

[tex]V_b = 3.80mL[/tex]

[tex]M_a = 0.10M[/tex] --- the given molarity of HCL

So, we have:

[tex]M_a * V_a = M_b * V_b[/tex]

[tex]0.10M * 9.50mL = M_b * 3.80mL[/tex]

Make Mb the subject

[tex]M_b = \frac{0.10M * 9.50mL}{3.80mL}[/tex] ---- The correct numerical setup

The solution is then calculated as:

[tex]M_b = \frac{0.10M * 9.50mL}{3.80mL}[/tex]

[tex]M_b = \frac{0.10 * 9.50}{3.80}M[/tex]

[tex]M_b = \frac{0.95}{3.80}M[/tex]

[tex]M_b = 0.25M[/tex]

.Write a short paragraph describing how electronegativity and molecular shape determine the polarity of a molecule. In your paragraph, describe why chemists consider relative electronegativity values and not absolute electronegativity values when determining the polarity of a bond. Also explain how a molecule with polar bonds can be non-polar overall

Answers

Answer:

See explanation

Explanation:

Electro negativity refers to the ability of an atom in a molecule to attract the shared pair of electrons of a bond closer to itself.

In a molecule, the polarity of bonds is determined by the relative electro negativity of the bonding atoms. If the difference in electro negativity between the atoms in a bond is significant, such a bond is polar in nature e.g H-Cl, H-Br, C-F, etc.

However, the occurrence of polar bonds in a molecule alone does not guarantee the polarity of the molecule. The polarity of a molecule also depends on the shape of the molecule since dipole moment is a vector quantity.

A molecule is polar when the resultant dipole moment which is determined by the shape of the molecule is non zero.

For instance, CO2 contains two polar C-O bonds but the molecule is non polar because the two dipole moments cancel out. Also, symmetrical molecules are nonpolar irrespective of the presence of polar bonds in the molecule.

4 NH3 + 7 O2 → 4 NO2 + 6 H2O What is the mole ratio between oxygen and nitrogen dioxide? 7 moles to 6 moles 4 moles to 6 moles 7 moles to 4 moles 4 moles to 4 moles

Answers

Answer:

7:4

Explanation:

O2 : NO2

7 : 4

hope this helps :)

helo in this please I'm so kunfused ​

Answers

OPTION C is the correct answer.

What type of molecule is shown below?

A. Ether
B. Alcohol
C. Aldehyde
D. Ketone

Answers

The answer is choice C. Adlehyde

The given molecule is an aldehyde with the formula HCHO. It is the simplest and primary aldehyde . Hence, option c is correct.

What are aldehydes ?

Aldehydes are a class of organic compounds that contain a carbonyl group (a carbon double-bonded to an oxygen) at the end of a carbon chain. The general formula for an aldehyde is RCHO, where R is a substituent or side chain attached to the carbonyl group.

Aldehydes are often characterized by their distinctive odor, which can be described as pungent and irritating. Some common aldehydes include formaldehyde (used in building materials and as a disinfectant), acetaldehyde (found in alcoholic beverages), and benzaldehyde (used in food flavorings).

Aldehydes are important intermediates in many chemical reactions, and they are used in a variety of industrial and laboratory applications. They can be synthesized by the oxidation of primary alcohols or by the partial oxidation of hydrocarbons. The given compound is formaldehyde HCHO.

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Atoms of which pair of elements will form ionic bonds in a compound?

Answers

One atom of sodium and one atom of fluorine
I think the answer is A

Which of the following describes the motion of water molecules in ice?
A. They do not move at all.
B. They are vibrating slightly.
C. They move the same as in a liquid.
D. They move faster than in a liquid.

Answers

B. They are vibrating slightly

Explanation:

This is because the particles are really close together and they vibrate on the spot.

Hope this is useful

Mark Brainliest please

Answer : the answer is B


The answer is option B "they are vibrating slightly." In ice the molecules are stuck together and shaking like a bunch of little people together trying to keep warm. ...


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