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
Stella [2.4K]
3 years ago
9

Even though we are well into the course Dumbledore notices some of the students are still having trouble with significant figure

s. Let’s review them once more: How many significant figures does the result of the following calculation have? (3.478-2.31)*(4.428-3.56)?
A) 1
B) 2
C) 3
D) 4
E) 5 2.
Chemistry
1 answer:
Sphinxa [80]3 years ago
5 0

Answer:

B) 2

Explanation:

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

The rule apply for the multiplication and division is :

The least number of significant figures in any number of the problem determines the number of significant figures in the answer.

The rule apply for the addition and subtraction is :

The least precise number present after the decimal point determines the number of significant figures in the answer.

(3.478-2.31) = 1.168 ≅ 1.17 (Rounded to least decimal digit)

(4.428-3.56) = 0.868 ≅ 0.87 (Rounded to least decimal digit)

So,

1.17 * 0.87 = 1.0  (Rounded to least significant)

Answer - two significant digits

You might be interested in
What is the concentration of a sodium hydroxide solution if 14.5 mL of it are exactly neutralized by 30.0 mL of a 0.500 M hydroc
rusak2 [61]

Answer:

1.03 M

Explanation:

Step 1: Write the balanced equation

NaOH + HCl ⇒ NaCl + H₂O

Step 2: Calculate the reacting moles of HCl

30.0 mL (0.0300 L) of 0.500 M HCl react.

0.0300 L × 0.500 mol/L = 0.0150 mol

Step 3: Calculate the moles of NaOH that react with 0.0150 moles of HCl

The molar ratio of NaOH to HCl is 1:1. The moles of NaOH that react are 1/1 × 0.0150 mol = 0.0150 mol.

Step 4: Calculate the molar concentration of NaOH

0.0150 moles of NaOH are in 14.5 mL (0.0145 L).

M = 0.0150 mol/0.0145 L = 1.03 M

4 0
3 years ago
How many moles of ions would you expect in an aqueous solution containing one mole of chromium(III) chloride? Hint: write out th
Cerrena [4.2K]

Answer:

Four  

Explanation:

AlCl₃(aq) ⟶ Al³⁺(aq) + 3Cl⁻(aq)

One mole of AlCl₃  produces 1 mol of Al³⁺ and 3 mol of Cl⁻.

That's four moles of ions.

8 0
2 years ago
Using the Bohr model, determine the energy, in joules, necessary to ionize a ground-state hydrogen atom. Show your calculations.
lord [1]

Answer:

The energy required to ionize the ground-state hydrogen atom is 2.18 x 10^-18 J or 13.6 eV.

Explanation:

To find the energy required to ionize ground-state hydrogen atom first we calculate the wavelength of photon required for this operation.

It is given by Bohr's Theory as:

1/λ = Rh (1/n1² - 1/n2²)

where,

λ = wavelength of photon

n1 = initial state = 1 (ground-state of hydrogen)

n2 = final state = ∞ (since, electron goes far away from atom after ionization)

Rh = Rhydberg's Constant = 1.097 x 10^7 /m

Therefore,

1/λ = (1.097 x 10^7 /m)(1/1² - 1/∞²)

λ = 9.115 x 10^-8 m = 91.15 nm

Now, for energy (E) we know that:

E = hc/λ

where,

h = Plank's Constant = 6.625 x 10^-34 J.s

c = speed of light = 3 x 10^8 m/s

Therefore,

E = (6.625 x 10^-34 J.s)(3 x 10^8 m/s)/(9.115 x 10^-8 m)

<u>E = 2.18 x 10^-18 J</u>

E = (2.18 x 10^-18 J)(1 eV/1.6 x 10^-19 J)

<u>E = 13.6 eV</u>

5 0
3 years ago
Which arrow represents the change of state described above? <br>L<br>N<br>O<br>P​
denis-greek [22]

Answer:

The answer is either o or p i think it is p

Explanation:

6 0
3 years ago
Read 2 more answers
Friction is the force that occurs when: A. one object attracts or repels another. B. one object is rubbing against another. C. o
AlladinOne [14]

Answer:

b i think. hope im not wrong

4 0
3 years ago
Read 2 more answers
Other questions:
  • 2NBr3 + 3NaOH = N2 +3NaBr + 3HOBr
    5·2 answers
  • You are on an island and need freshwater to drink. Which process could you
    11·1 answer
  • Explain how scientific knowledge and reasoning can help us make difficult decisions.
    15·1 answer
  • Which family is most likely to form a 2+ ion?
    6·1 answer
  • According to one theory, the pressure of a gas increases as its volume decreases, because the molecules in the gas have to move
    9·1 answer
  • How many total atoms are there in 69.1 g of ammonia (NH3)?​
    9·1 answer
  • Which of following is true of liquids?
    14·2 answers
  • if you push the head of a nail against your skin and then push the point of the same nail against your skin with the same force
    9·1 answer
  • 1. What is the Charlotte?<br> A. A train<br> B. A car<br> D. An airplane<br> C. A ship
    15·1 answer
  • Activity acid bases solutions project need help !!!!
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!