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3 years ago

Which of the following statements is not correct?

1 answer:

4 0

To answer the question above, multiply the given number of moles by the molar masses.

(A) (0.20 mole) x (32 g / 1 mole) = 6.4 grams O2
(B) (0.75 mole) x (62 g / 1 mole) = 46.5 grams H2CO3
(C) (3.42 moles) x (28 g / 1 mole) = 95.7 grams CO
(D) (4.1 moles) x (29.88 g / 1 mole) = 122.508 g Li2O

The answer to the question above is letter D.

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Which object can electrically polarized

kobusy [5.1K]

Answer:Static electricity works because objects which are otherwise "neutral" (in other words, objects with no net charge) can be polarized. An electric field, like one caused by a nearby charged object, can cause the charges inside of a neutral object — the protons and electrons — to move around a tiny bit.

Explanation:

5 0

2 years ago

During lab, a student used a Mohr pipet to add the following solutions into a 25 mL volumetric flask. They calculated the final

kompoz [17]

Answer:

(FeSCN⁺²) = 0.11 mM

Explanation:

Fe ( NO3)3 (aq) [0.200M] + KSCN (aq) [ 0.002M] ⇒ FeSCN+2

M (Fe(NO₃)₃ = 0.200 M

V (Fe(NO₃)₃ = 10.63 mL

n (Fe(NO₃)₃ = 0.200*10.63 = 2.126 mmol

M (KSCN) = 0.00200 M

V (KSCN) = 1.42 mL

n (KSCN) = 0.00200 * 1.42 = 0.00284 mmol

Total volume = V (Fe(NO₃)₃ + V (KSCN)

= 10.63 + 1.42

= 12.05 mL

Limiting reactant = KSCN

So,

FeSCN⁺² = 0.00284 mmol

M (FeSCN⁺²) = 0.00284/12.05

= 0.000236 M

Excess reactant = (Fe(NO₃)₃

n(Fe(NO₃)₃ = 2.126 mmol - 0.00284 mmol

=2.123 mmol

For standard 2:

n (FeSCN⁺²) = 0.000236 * 4.63

=0.00109

V(standard 2) = 4.63 + 5.17

= 9.8 mL

M (FeSCN⁺²) = 0.00109/9.8

= 0.000111 M = 0.11 mM

Therefore, (FeSCN⁺²) = 0.11 mM

7 0

2 years ago

Which statements correctly describe the decay rates of radioactive isotopes?

storchak [24]

Answer: b} The exact time when an individual atom will decay can be accurately predicted.

c} After each half-life, the amount of radioactive material is reduced by half.

Explanation:

All radioactive decay follows first order kinetics.

Rate law expression for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = time taken for decay process

a = initial amount of the reactant

a - x = amount left after decay process

Expression for calculating half life, which is the time taken by the half of the reactants to decompose is:

$t_{1/2}=\frac{0.693}{k}$

4 0

2 years ago

Read 2 more answers

What elements are being reduced and oxidized in this chemical formula?

dangina [55]

Answer: The element Na (Sodium) is getting oxidized and Hydrogen is getting reduced.

Explanation:

Oxidation reactions are the reactions in which addition of oxygen takes place.

Reduction reactions are the reactions in which loss of oxygen takes place.

For a given reaction:

$2Na(s)+2H_2O(l)\rightarrow H_2(g)+2NaOH(aq.)$

Sodium is getting oxidized because there is an addition of reaction with that element.

Hydrogen is getting reduced because there is a removal of oxygen with that element.

3 0

2 years ago

A 10 gram sample of iron reacts with oxygen to form 18.2 grams of ferric oxide. How many grams of oxygen reacted?

RoseWind [281]

Answer:

$\boxed {\boxed {\sf 8.2 \ grams}}$

Explanation:

According to the Law of Conservation of Mass, the mass of the products must equal the mass of the reactants.

mass products = mass reactants

In this problem, the reaction is:

$iron + oxygen = ferric \ oxygen$

The reactants are iron and oxygen. We know the mass of the iron sample is 10 grams.

The product is ferric oxide. The mass of the ferric oxide sample is 18.2 grams.

$10 \ g + oxygen=18.2 \ g$

We want to find how many grams of oxygen reacted. We have to get the oxygen by itself. 10 is being added to oxygen. The inverse of addition is subtraction. Subtract 10 from both sides of the equation.

$10 \ g - 10 \ g+ oxygen = 18.2 \ g - 10 \ g$

$oxygen= 18.2 \ g - 10 \ g$

$oxygen= 8.2 \ g \\$

<u>8.2 grams of oxygen </u>reacted with 10 grams of iron to form 18.2 grams of ferric oxide.

8 0

2 years ago