1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Westkost [7]
3 years ago
7

How many centimeters are in 25 kilometers?

Chemistry
2 answers:
kramer3 years ago
6 0
A. 
25km x 10^3m/1km x 1cm/10^-2m 
cancel out km and m left with cm 
Zarrin [17]3 years ago
3 0

its A 2.5 x 10^6 took the test

You might be interested in
A student hypothesized that the amount of sunlight a sunflower plant receives determines the number of sunflower seeds the plant
BabaBlast [244]

Answer:

Dependent variable

Explanation:

In every experiment, there must be a dependent variable and an independent variable.

The independent variable is that variable that you have to manipulate in order to receive a response. E.g, in the experiment described in the question, the amount of sunlight a sunflower plant receives is the independent variable.

The dependent variable is the number of seeds produced. It is the response obtained by carefully manipulating the amount of sunlight

5 0
3 years ago
If you react 2.00 g of hydrogen completely using 15.87 g of oxygen to produce water, how much water (in grams) will you have?
leonid [27]

Answer:

The amount (mass) of water we will have is 17.869 grams

Explanation:

The molar mass of hydrogen gas H₂ = 2.016 grams/mole

The molar mass of oxygen gas = 31.999 g/mol

Therefore, 2.00 g of hydrogen will give;

2.00/2.016 = 0.9921 moles of H₂ gas and

15.87 g of O₂ will give;

15.87/31.999 = 0.49595 moles

The reaction is as follows;

2H₂ (g) + O₂ (g) → 2H₂O (l)

Two moles of H₂ react with one mole of O₂ to produce two moles of H₂O

Therefore 0.9921 moles of H₂ will react with 0.9921/2 or 0.49595 moles of O₂ to produce 0.9921 moles of H₂O

From the above we note that all the H₂ and O₂ are completely consumed to form 0.9921 moles of H₂O

Molar mass of H₂O = 18.01528 g/mol

Number of moles = Mass/(Molar mass)

∴ Mass of H₂O = (Molar mass) × (Number of moles)

= 18.01528 g/mol × 0.9921 moles = 17.869 grams

Therefore the amount (mass) of water we will have = 17.869 grams.

8 0
3 years ago
How many molecules are in 23 moles of oxygen (O2)? Round the answer to one digit past the decimal point. If the answer is less t
melamori03 [73]

To Find :

How many molecules are in 23 moles of oxygen (O₂).

Solution :

We know, 1 mole of any atom/molecule contains 6.022 × 10²³ numbers of atoms/molecules.

So, number of molecules in 23 moles of O₂ are :

n= 23\times 6.022\times 10^{23}\\\\n =138.506\times 10^{23}\\\\n = 1.385 \times 10^{25}\ molecules

Hence, this is the required solution.

6 0
3 years ago
In a 200 cm3 container, a certain amount of O2 gas is held with a piston at equilibrium with the external pressure being 1 bar.
Maslowich

Answer:

a) V2 = 200.161 cm³

b)  Wexp = 0.0161 J done by the system

c) ΔU = 1.984 J

d) ΔH = 2.006 J

Explanation:

ΔU = Q + W.....first law

a) at constant temperature (298 K ):

∴ ΔU = 0 ⇒ Q = - W

∴ W = - ∫ P dV

⇒ Q = ∫ PdV

∴ PV = nRT

⇒ P = nRT / V

⇒  Q = ∫ nRT dV/V

⇒ Q = nRT Ln ( V2 / V1 )....assuming n O2 = 1 mol

⇒  Q / nRT = Ln ( V2 / V1 )

⇒ 2 J / (( 1mol) ( 8.314 J/molK * 298 K )) = Ln ( V2 / V1 )

⇒ 8.072 E-4 = Ln ( V2 / V1 )

⇒ 1.001 = V2 / V1

⇒ V2 = 1.001 * 200 cm³

⇒ V2 = 200.161 cm³  ( 2.00161 E-4 m³)

b) Wexp = - ∫ PdV.......work done by the system ( - )

P = 1 bar = 10197.2 Kgf/m²

⇒ W exp = - 10197.2 Kgf/m² * ( 2.00161 E-4 - 2.00 E-4 )m³

⇒ W exp = - 1.642 E-3 Kgf *m ( - 0.0161 J )

c) ΔU = Q + W

⇒ ΔU = 2 J - 0,0161 J

⇒ ΔU = 1.984 J   ( 0.202 Kgf*m )

d) H = U + PV.....ideal gas

⇒ ΔH = Δ ( U + PV )

⇒ ΔH = ΔU + P2V2 - P1V1

⇒ ΔH = 0.202  + (( 10197.2 * 2.00161 e-4 )) - (( 10197.2 * 2.00 E-4 ))

⇒ ΔH = 0.202 + 2.041 - 2.0394

⇒ ΔH = 0,204 Kgf*m ( 2.006 J )

8 0
4 years ago
How is making an apple pie different from making lead iodide
Nataly_w [17]

Explanation:

An apple pie is a mixture whereas lead iodide is a compound. To processes leading to the formation of a mixture and a compound are completely different.

  • A compound is a substance composed of two or more kinds of atoms that are joined together to form a definite matter.
  • The properties of the compound formed differs from that of the constituent atoms.
  • A mixture on the other hand is made up of indefinite compositions.
  • In the case of the apple pie, the parts are not homogeneous in nature.

To produce lead iodide, chemical reactions must take place between atoms.

In the case of  the pie, chemical and physical changes can take place.

Learn more:

Mixture brainly.com/question/1446244

#learnwithBrainly

4 0
4 years ago
Other questions:
  • A collection of coins contains 15 pennies, 12 dimes, and 7 quarters. What is the percentage of pennies in the collection? Expres
    12·1 answer
  • In a chemical formula what number indiates the rtio of atoms in the compound
    15·1 answer
  • What would happen if Phosphorus disappeared?
    10·1 answer
  • Harry Hess resurrected Wegener’s continental drift hypothesis and also the mantle convection idea of Holmes.
    13·2 answers
  • What is the percent abundance of Pt-198, if the average atomic mass of platinum is 195.16 and platinum has four naturally occurr
    12·1 answer
  • Allicin contains 59.9 g of carbon, 21.7 g of hydrogen, 24.4 g of oxygen, and sulfur. What is the mass percent of sulfur in a 162
    12·1 answer
  • In a first-order reaction, what is the rate constant if the rate is 0.050 moles/l-sec and the reactant concentration is 0.030 mo
    5·1 answer
  • Write the given numbers in standard notation, maintaining the same number of significant figures.
    13·1 answer
  • Explain how trait are governed by the genetic material found in the genes within chromosomes in the cell nucleus.
    10·2 answers
  • Element and Compound
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!