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2 years ago

What is the sum of 2.7 g and 2.47g expressed in the correct number of significant digits

Chemistry

2 answers:

Anastasy [175]2 years ago

6 0

Answer : The answer will be, 5.2 g

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 addition and subtraction is :

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

As we are given that the sum of 2.7 g and 2.47 g.

$2.7g+2.47g$

$\Rightarrow 5.17g$

In the given expression, 2.7 has 2 significant figures and 2.47 has 2 significant figures. From this we conclude that least precise number present after the decimal point is 1.

Thus, the answer will be $\Rightarrow 5.2g$

NeTakaya2 years ago

5 0

In order to get the sum of 2.7 and 2.47, we will add both numbers. So, 2.7 plus 2.47 would be 5.17. And the correct number of significant digits in this number is still the same, 5.17, so we have three significant numbers. Why? There are three rules in identifying the significant figures: 1. Non zeros are always significant (which this applies in our sum above). 2. Any zeros in between significant numbers are always significant. 3. <span> The final zero or zeros in the decimal portion only are significant.</span>

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dsp73

Answer:

1384 kJ/mol

Explanation:

The heat absorbed by the calorimeter is equal to the heat released due to the combustion of the organic compound. C is the total heat capacity of the calorimeter and Δt is the change in temperature from intial to final:

Q = CΔt = (3576 J°C⁻¹)(30.589°C - 25.000°C) = 19986.264 J

Extra significant figures are kept to avoid round-off errors.

We then calculate the moles of the organic compound:

(0.6654 g)(mol/46.07) = 0.0144432 mol

We then calculate the heat released per mole and convert to the proper units. (The conversion between kJ and J is infinitely precise and is not involved in the consideration of significant figures)

(19986.264 J)(1kJ/1000J) / (0.0144432 mol) = 1384 kJ/mol

8 0

3 years ago

How many grams of glucose, C6H12O6, in 2.47 mole?

statuscvo [17]

First, we need to find the atomic mass of $C_{6}H_{12}O_{6}$ .

According to the periodic table:
The atomic mass of Carbon = C = 12.01
The atomic mass of Hydrogen = H = 1.008
The atomic mass of Oxygen = O = 16

As there are 6 Carbons, 12 Hydrogens and 6 Oxygens, therefore:
The molar mass of   $C_{6}H_{12}O_{6}$ = 6 * 12.01 + 12 * 1.008 + 6 * 16

The molar mass of   $C_{6}H_{12}O_{6}$ = 180.156 grams/mole

Now that we have the molar mass of   $C_{6}H_{12}O_{6}$ , we can find the grams of glucose by using:

mass(of glucose in grams) = moles(of glucose given in moles) * molar mass(in grams/mole)

Therefore,
mass(of glucose in grams) = 2.47 * 180.156
mass(of glucose in grams = 444.99 grams

Ans: Mass of glucose in grams in 2.47 moles = 444.99 grams

-i

6 0

3 years ago

Read 2 more answers

Which element does this atom represent?

Maurinko [17]

Answer:

Option C is correct = fluorine

Explanation:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

This diagram show that there are 9 electrons and 9 protons are present. We know that the number of protons or electrons are atomic number of that element. From periodic table we know that atomic number of fluorine is 9 thus the given atom present fluorine atom.

3 0

3 years ago

Which of the following best describes where cellular respiration occurs?

Illusion [34]

Answer:

In every body cell

Explanation:

4 0

3 years ago

Read 2 more answers

Using the following equation: 3H2SO4+ 2Fe -> Fe2(SO4)3+ 3H2

Mariana [72]

Answer:

H₂SO₄

Explanation:

Given data:

Number of moles of H₂SO₄ = 15 mol

Number of moles of Fe = 13 mol

Which reactant is limiting reactant = ?

Solution:

Chemical equation:

3H₂SO₄ + 2Fe → Fe₂(SO₄)₃ + 3H₂

now we will compare the moles reactant with product.

H₂SO₄ : Fe₂(SO₄)₃

3 : 1

15 : 1/3×15 = 5

H₂SO₄ : H₂

3 : 3

15 : 15

Fe : Fe₂(SO₄)₃

2 : 1

13 : 1/2×13 = 6.5

Fe : H₂

2 : 3

13 : 3/2×13 = 19.5

Number of moles of product formed by H₂SO₄ are less thus it will act as limiting reactant.

8 0

3 years ago