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2 years ago

Give the number of significant figures in this number: 40.00

Chemistry

2 answers:

erica [24]2 years ago

5 0

Answer:

Explanation:

because the follow digits are part of the answer even though they are following a decimal

Tatiana [17]2 years ago

4 0

A significant figure is every symbol that made the number itself.

In this case, the number 40.00 has four figures but only two of them are significant 40, this is because you haven't got any more decimals than the first zero.

If you have a case with zeros in front, you take to the first non zero digits.

For example, 0.071004 you wold express as 0.071 and those 7, and 1 are the significant ones.

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The chemical reaction that causes chromium to corrode in air is given by 4Cr+3O2→2Cr2O3 in which at 298 K ΔH∘rxn = −2256 kJ ΔS∘r

MAVERICK [17]

Answer:

-2092 kJ

Explanation:

Let's consider the chemical reaction that causes chromium to corrode in air.

4 Cr + 3 O₂ → 2 Cr₂O₃

We can calculate the standard Gibbs free energy (ΔG°) using the following expression.

ΔG° = ΔH° - T × ΔS°

where,

ΔH°: standard enthalpy of the reaction

T: absolute temperature

ΔS°: standard entropy of the reaction

ΔG° = -2256 kJ - 298 K × (-0.5491 kJ/K)

ΔG° = -2092 kJ

5 0

2 years ago

Read 2 more answers

In 1980,the US produced 18.4 billion(10to the power of 9)pounds of phosphoric acid to be used in the manufacture of fertilizer.t

sertanlavr [38]

18.4 * 10^9 lbs = (18.4 * 10^9)/2000 tons

Cost = ((18.4 * 10^9)/2000 ) * 318

Cost = $ 2925600000

6 0

2 years ago

Read 2 more answers

Give two areas where the compressible nature of gas is applied

galina1969 [7]

Answer:

1. Gases can be easily liquefied into very small volumes and stored in liquid form Eg in LPGA cylinders and used in homes.

2. Balloons can be easily filled with air.

6 0

1 year ago

How many moles of chromium metal equal 7.52 × 1022 atoms Cr?

grigory [225]

Answer:

0.125 mole

Explanation:

From Avogadro's hypothesis, we discovered that 1 mole of any substance contains 6.02x10^23 atoms.

The statement above suggests that 1 mole of chromium contains 6.02x10^23 atoms.

Now, if 1mole of of chromium contains 6.02x10^23 atoms,

Then Xmol of chromium contains 7.52x10^22 atoms i.e

Xmol of chromium = 7.52x10^22/6.02x10^23

Xmol of chromium = 0.125 mole

Therefore, 0.125 mole of chromium contains 7.52x10^22 atoms

8 0

2 years ago

The nuclear equation is incomplete. Superscript 239 Subscript 94 Baseline P u + Superscript 1 Subscript 0 Baseline n yields Supe

Likurg_2 [28]

Answer:

The correct option is the first option

Explanation:

The equation described in the question is shown below

²³⁹₉₄Pu +¹₀n ⇒ ¹⁰⁰₄₀Zr + blank + 2¹₀n

This equation is a nuclear fission because it involves the splitting of a heavy nucleus, Plutonium (Pu), into smaller nuclei, Zirconium (Zr) and an unknown nuclei.

The law of conservation of matter states that matter can neither be created nor destroyed hence in other to get the missing atom, we must know the total number of subscripts (mass number) and superscripts (atomic number) on both sides.

The total mass number on the reactant side is 239 + 1 = 240

The total atomic number on the reactant side is 94 + 0 = 94

While, The total mass number on the product side is 100 + 2(1) = 102

The total atomic number on the product side is 40 + 2(0) = 40

To determine the missing atom, you subtract the the total atomic number of the product from that on the reactant side; 94 - 40 = 54

The atom with the atomic number 54 is Xenon,

To determine the mass number of the xenon isotope involved, you subtract the the total mass number of the product from that on the reactant side; 240 - 102 = 138.

Hence, the particle that completes the equation is ¹³⁸₅₄Xe, the first option

5 0

2 years ago