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
Dima020 [189]
3 years ago
11

How often do girls normally experience menstruation a.once every 30 days b. once every 29 c.once every 28 d.once every 27

Chemistry
2 answers:
Lana71 [14]3 years ago
6 0

Answer:

Once every 28 days

Explanation:

I am not 100% sure because i am not female but i do remember that in my health class it said it was once every 28 days

kramer3 years ago
5 0

Answer:

i think answer is a, every 30 days

You might be interested in
Why are alphabets in the order they are?
sineoko [7]
Its arbitrary. It was developed on the greek phoenetic system and never reallybwas explained.
4 0
3 years ago
when 6.25 grams of pure iron are allowed to react with oxygen , a black oxide forms. if the product weighs 8.15 g, what is the e
erik [133]
We are given with the mass of  pure iron that reacts with oxygen to form an oxide which has a given mass as well. the mass of oxygen reacted is 8.15-6.25 g or 1.9 grams. THen we convert the mass of the reactants to moles. Iron is equal to 0.1119 moles and oxygen is equal to 0.1188. We divide each number to the less amount. Hence iron is 1 and oxygen is approx 1. The empirical formula hence is FeO or ferrous oxide or Iron (II) oxide.
5 0
3 years ago
How many moles of C2H2 are needed to react completely with 84.0 mol O2?
Airida [17]
33.6 moles are needed to completely react with 84.0 moles of O2
3 0
3 years ago
Read 2 more answers
What is 0.00550 g converted to mg
Mila [183]

Answer: it is 5.5 mg

Explanation:

you have to multiply the mass value by 1000

5 0
3 years ago
Calculate the enthalpy of formation of butane, C4H10, using the balanced chemical
melisa1 [442]

Answer:

-125.4

Explanation:

Target equation is 4C(s) + 5H2(g) = C4H10

These are the data equations for enthalpy of combustion

  1. C(s) + O2(g) =O2(g) -393.5 kJ/mol * 4
  2. H2(g) + ½O2(g) =H20(l) = 285.8 kJ/mol * 5
  3. 2CO2(g) + 3H2O(l) = 13/2O2 (g) + C4H10 - 2877.1 reverse

To get target equation multiply data equation 1 by 4; multiply equation 2 by 5; and reverse equation 3, so...

Calculate 4(-393.5) + 5(-285.8) + 2877.6 and you should get the answer.

7 0
3 years ago
Other questions:
  • How do unbalanced forces affect its motion when the object is at rest?
    9·1 answer
  • When an atom becomes an ion does its mass number change?
    7·1 answer
  • What are they h-bond water acceptors in fentanyl, and is it souluable in water? Explain why or why not.
    13·1 answer
  • Write the net ionic equation for this reaction occurring in water: ammonium fluoride and magnesium chloride are mixed to form ma
    10·1 answer
  • Does the following statement describes a function of DNA, a function of RNA, of both DNA and RNA, or a function of neither DNA o
    9·2 answers
  • Much of the general structure and physical properties of the interior of the earth are inferred from:
    15·2 answers
  • Nick wanted to see how high an ice cube would float in different temperatures of water. Identify the independent variable.
    7·2 answers
  • Has boiling vents in the datk door
    9·1 answer
  • At the beginning of the industrial revolution in 1850, the CO2concentration was 280 ppm. Today, it is 410 ppm.
    9·1 answer
  • PLEASE HELPPPPPPP:
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!