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
egoroff_w [7]
3 years ago
15

A van moves 50 miles with a constant speed of 20 mph and another 84 miles with a constant speed of 56 mph. How much time in tota

l does it take to travel these distances?
A) 1 hour
B) 4 hours
C) 1.5 hours
D) 2.5 hours
Chemistry
1 answer:
arlik [135]3 years ago
3 0

Answer:

B) 4 hours

Explanation:

the equation relating speed , distance and time is as follows

speed = distance / time taken

the van moves 50 miles at 20 mph and the next 84 miles at 56 mph

so lets calculate the time taken at both speeds

substituting the values in the above equation

20 mph = 50 miles  / time

time taken = 50 / 20 = 2.5 hours

56 mph = 84 miles / time

time taken = 1.5 hours

the totat time taken is - 2.5 + 1.5 = 4 hours

You might be interested in
If an unknown sample contains 39.04% sulfuric acid by mass, then a 0.9368 g of that sample would require _____ mL of 0.2389 M Na
bonufazy [111]

Answer:

A) 31.22

Explanation:

The reaction of sulfuric acid with NaOH is:

H₂SO₄ + 2 NaOH → Na₂SO₄ + 2H₂O

To solve this problem we need to determine the moles of acid that will react, and, using the chemical equation we can determine the moles of NaOH and the volume that a 0.2389M NaOH solution would require to neutralize it.

<em>Moles H₂SO₄ (Molar mass: 98.08g/mol):</em>

0.9368g * 39.04% = 0.3657g H₂SO₄ * (1mol / 98.08g) =

3.7289x10⁻³moles H₂SO₄

And moles of NaOH that you require to neutralize the acid are:

3.7289x10⁻³moles H₂SO₄ * (2 moles NaOH / 1 mole H₂SO₄) =

7.4578x10⁻³ moles NaOH

Using a 0.2389M NaOH solution:

7.4578x10⁻³ moles NaOH * (1L / 0.2389mol) = 0.03122L = 31.22mL

Right answer is:

<h3>A) 31.22 </h3>

5 0
3 years ago
How are DNA, genes and chromosomes related
zysi [14]
Chromosomes have genes, and genes are segments of DNA.
3 0
3 years ago
Read 2 more answers
Why melting point of Fe in blast furnace is lower than ellingham?
Kaylis [27]

Answer:

Because they are different oxides.

Explanation:

In both processes they are involve Iron Oxides, but in the case of Ellingham diagrams, it is consider the Iron in combination with oxygen to form FeO, so the melting point is around 1600  ºC. In the case of blast furnace, the Fe that is present in the ores, are primary the hematite (Fe2O3) and the magnetite (Fe3O4).

6 0
3 years ago
5g of aspirin will powder will take effect more quickly than a 5g aspirin tablet because the powder has more what
Pani-rosa [81]

Answer:

Explanation:

Because the powder has more finer and larger surface area hence it absorbed faster and it becomes more effective in performance compared to the tablet that will still need to be dissolved before it is been assimilated into the body system.

7 0
3 years ago
How many liters of oxygen gas, at standard
Karo-lina-s [1.5K]

Answer:

Explanation:

  • For the balanced reaction:

<em>4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)​.</em>

It is clear that 4 mol of Fe react with 3 mol of O₂ to produce 2 mol of Fe₂O₃.

  • Firstly, we need to calculate the no. of moles of 35.8 grams of Fe metal:

no. of moles of Fe = mass/molar mass = (35.8 g)/(55.845 g/mol) = 0.64 mol.

  • Now, we can find the no. of moles of O₂ is needed to react with the proposed amount of Fe:

<em><u>Using cross multiplication:</u></em>

4 mol of Fe is needed to react with → 3 mol of O₂, from stichiometry.

0.64 mol of Fe is needed to react with → ??? mol of O₂.

∴ The no. of moles of O₂ needed = (3 mol)(0.64 mol)/(4 mol) = 0.48 mol.

  • Finally, we can get the volume of oxygen using the information:

<em>It is known that 1 mole of any gas occupies 22.4 L at standard P and T (STP).</em>

<em></em>

<em><u>Using cross multiplication:</u></em>

1 mol of O₂ occupies → 22.4 L, at STP conditions.

0.48 mol of O₂ occupies → ??? L.

∴ The no. of liters of O₂ = (0.48 mol)(22.4 L)/(1 mol) = 10.752 L.

5 0
3 years ago
Other questions:
  • Estimate the freezing and normal boiling points of 0.25 m aqueous solutions of nh4no3 nicl3 al2so43
    8·1 answer
  • . How can a change that occurs downstream in a river ecosystem (that is, a dam) affect the rest of that ecosystem?
    13·1 answer
  • William adds two values, following the rules for using significant figures in computations. He should write the sum of these two
    12·2 answers
  • 2. 85.6 GRAMS of RbBr
    7·1 answer
  • Pentane gas reacts with oxygen gas to give carbon dioxide gas and water vapor (gas). If you mix pentane and oxygen in the correc
    14·1 answer
  • 6. Alternating electricity (AC) is produced in power plants when the fuel is burned and water
    15·1 answer
  • Name the gases that mostly compose the atmosphere.
    11·1 answer
  • I NEED HELP PLEASE HELP ME I'LL GIVE BRAINLIEST IT HAS TO BE RIGHT OR IMMA FAIL PLEASEEEEE
    14·2 answers
  • 20. 6th-grade question
    6·1 answer
  • Calculate the pH of the 4M NaOH
    12·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!