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
bulgar [2K]
3 years ago
11

If an athlete runs at a speed of 12.9 km/hour, how long will it take the athlete to run a marathon (about 42.2 km)? Express your

answer in hours using the correct number of significant figures. Do not enter your answer using scientific notation.
Chemistry
1 answer:
jekas [21]3 years ago
7 0

Answer:

Time = 3.27s

Explanation:

Time = Distance / Speed

Time = 42.2 / 12.9 = 3.2713

When you multiply the number of significant figures in the result is the same as the number with the least significant figures.

In this case 42.2 has 3 significant figures and 12.9 also has 3 significant figures, therefore the answer must have 3 significant figures too.

Time = 3.27 s

You might be interested in
How many grams of nitric acid HNO₃, are required to neutralize (completely react with) 4.30 grams of Ca(OH)2 according to the ac
Brrunno [24]

Answer:

7.32g of HNO3 are required.

Explanation:

1st) From the balanced reaction we know that 2 moles of HNO3 react with 1 mole of Ca(OH)2 to produce 2 moles of H2O and 1 mole of Ca(NO3)2.

From this, we find that the relation between HNO3 and Ca(OH)2 is that 2 moles of HNO3 react with 1 mole of Ca(OH)2.

2nd) This is the order of the relations that we have to use in the equation to calculate the grams of nitric acid:

• starting with the 4.30 grams of Ca(OH)2.

,

• using the molar mass of Ca(OH)2 (74g/mol).

,

• relation of the 2 moles of HNO3 that react with 1 mole of Ca(OH)2 .

,

• using the molar mass of HNO3 (63.02g/mol).

4.30g\text{ Ca\lparen OH\rparen}_2*\frac{1\text{ mol Ca\lparen OH\rparen}_2}{74g\text{ Ca\lparen OH\rparen}_2}*\frac{2\text{ moles HNO}_3}{1\text{ mole Ca\lparen OH\rparen}_2}*\frac{63.02g\text{ HNO}_3}{1\text{ mole HNO}_3}=7.32g\text{ HNO}_3

So, 7.32g of HNO3 are required.

4 0
1 year ago
WILL MARK BRAINLIEST!
jarptica [38.1K]

An atomic mass unit is defined as precisely 1/12 the mass of an atom of carbon-12.

7 0
3 years ago
Draw a structure for an alcohol that exhibits a molecular ion at M+ = 74 and that produces fragments at m/z = 59, m/z = 56 and m
pychu [463]

Answer:

Please refer to the attachment below for answer and explanation.

Explanation:

Please refer to the attachment below for answer and explanation.

6 0
3 years ago
What is the mass in grams of 5.00moles of CH4?
anastassius [24]

Answer:

1. 80g

2. 1.188mole

Explanation:

1. We'll begin by obtaining the molar mass of CH4. This is illustrated below:

Molar Mass of CH4 = 12 + (4x1) = 12 + 4 = 16g/mol

Number of mole of CH4 from the question = 5 moles

Mass of CH4 =?

Mass = number of mole x molar Mass

Mass of CH4 = 5 x 16

Mass of CH4 = 80g

2. Mass of O2 from the question = 38g

Molar Mass of O2 = 16x2 = 32g/mol

Number of mole O2 =?

Number of mole = Mass /Molar Mass

Number of mole of O2 = 38/32

Number of mole of O2 = 1.188mole

6 0
3 years ago
With the levels closest to the nucleus of
Dmitry_Shevchenko [17]

Answer:

The first energy level is closest to the nucleus. The second energy level is a little farther away than the first. ... The electrons in the energy level farthest from the nucleus are called valence electrons. Atoms in the same column (group) in the periodic table have the same number of valence electrons.

Explanation:

5 0
2 years ago
Other questions:
  • Identify the products that are in equilibrium with NH3 and H2O.Identify the products that are in equilibrium with and .NH2−and H
    12·2 answers
  • The pH of acid J is 4. The pH of acid K is 6. How much more acidic is acid J than<br> acid K?
    10·1 answer
  • How did robert hooke contribute to the cell theory?
    5·1 answer
  • Classify the following compounds as ionic or covalent: a. MgCl2 b. Na2S c. H2O d. H2S
    10·2 answers
  • How many moles of h2so4 are needed to make 85 ml of .750 m solution?
    9·1 answer
  • When a reaction between Magnesium and Hydrochloric acid take place the mass of the reactants is more than the mass of the produc
    8·1 answer
  • Many people think that summer is warmer because the earth is closer to the sun at that time of year. explain why
    5·1 answer
  • Which root word of the binary ionic compound ends with -ide?
    8·2 answers
  • The temperature of 150 mL of water is 25°C. What must happen for the temperature of the water to increase to 35°C?
    15·1 answer
  • Edit al least six lines to obtain energy​
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!