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3 years ago

How many moles of gold are there in 4.80 ounces of gold?

2 answers:

7 0

Hi,

One mole= 197 grams
4.8 ounces= 136.078

So there are
$\boxed{0.6908685764156386}$ moles of gold in 4.80 ounces of gold.

NemiM [27]3 years ago

5 0

0.682 gold ...........

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When molecules have the same number of each element but those atoms are arranged differently they are known as____________.

Karo-lina-s [1.5K]

Answer: Structural Isomers

Explanation:

The compounds having similar molecular formula but different arrangement of atoms or groups in space are called isomers and the phenomenon is called as isomerism.

Isomers are of two types: structural isomers and stereo isomers.

Structural isomers are isomers in which molecules with the same molecular formula have different bonding patterns.

Stereoisomers are isomers in which molecules have the same molecular formula and sequence of bonded atoms but differ in the three-dimensional orientations of their atoms in space.

Thus when molecules have the same number of each element but those atoms are arranged differently they are known as Structural isomers.

5 0

2 years ago

If 25.0 g NO are produced, how many grams of nitrogen gas are used?

mr Goodwill [35]

Using the stoichiometry of the reaction and the information provided in the question, the mass of N2 used is 11.62 g.

<h3>Chemical reaction</h3>

The term chemical reaction refers to the combiantion of two or substances to yiled one or more products. The reaction equation in this case is N2 + O2 --->2NO.

Now;

Number of moles of NO = 25g/30 g/mol = 0.83 moles

1 mole of N2 yields 2 moles of NO

x moles of N2 yileds 0.83 moles of NO

x = 0.415 moles

Mass of N2 = 0.415 moles * 28 g/mol = 11.62 g

Learn more about stoichiometry:

brainly.com/question/12166462

8 0

2 years ago

If we start with 1.000 g of strontium-90, 0.805 g will remain after 9.00 yr. This means that the of strontium-90 is ________ yr.

lesantik [10]

The question is incomplete, here is the complete question.

If we start with 1.000 g of strontium-90, 0.805 g will remain after 9.00 yr. This means that the half-life of strontium-90 is ________ yr.

a. 28.8 b. 30.9 c. 35.4 d. 32.2

Answer : The half-life of strontium-90 is 28.8 years.

Explanation :

This is a type of radioactive decay and all radioactive decays follow first order kinetics.

First we have to calculate the rate constant.

Expression for rate law for first order kinetics is given by :

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

where,

k = rate constant

t = time taken for decay process = 9.00 year

a = initial amount or moles of the reactant = 1.000 g

a - x = amount or moles left after decay process = 0.805 g

Putting values in above equation, we get:

$k=\frac{2.303}{9.00}\log\frac{1.00}{0.805}$

$k=0.0241\text{ year}^{-1}$

To calculate the half-life, we use the formula :

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

$0.0241\text{ year}^{-1}=\frac{0.693}{t_{1/2}}$

$t_{1/2}=28.8\text{ years}$

Therefore, the half-life of strontium-90 is 28.8 years.

5 0

3 years ago

Why is molybdenum a good conductor of electricity

SCORPION-xisa [38]

Answer: Because it is has a strong connection

Explanation:

7 0

3 years ago

(7) A 955 gram piece of tungsten metal is heated from 18°C to 100°C. The amount of heat absorbed

Ber [7]

Answer:

The answer to your question is: Cp = 0.129 J/g°C

Explanation:

Data

mass = 955 g of tungsten

T1 = 18°C

T2 = 100°C

Q = 10180 Joules

Cp = ?

Formula

Q = mCpΔT

Clear Cp from the equation

Cp = Q / mΔT

Substitution

Cp = 10180 / (955(100-18))

Cp = 10180 / (955(82))

Cp = 10180 / 78310

Cp = 0.129 J/g°C

3 0

3 years ago