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lesya [120]
3 years ago
7

How many atoms of lead are in 3.5 moles of lead?

Chemistry
1 answer:
vagabundo [1.1K]3 years ago
3 0

Answer:

2.1 × 10²⁴ atoms Pb

Explanation:

Avogadro's number: 6.022 × 10²³

Step 1: Find conversions

1 mol Pb = 6.022 × 10²³ atoms Pb

Step 2: Use Dimensional Analysis

3.5 \hspace{3} mol \hspace{3} Pb(\frac{6.022(10)^{23} \hspace{3} atoms \hspace{3} Pb}{1 \hspace{3} mol \hspace{3} Pb} ) = 2.107 × 10²⁴ atoms Pb

Step 3: Simplify

We have 2 sig figs.

2.107 × 10²⁴ atoms Pb ≈ 2.1 × 10²⁴ atoms Pb

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What is the mass, in grams, of 2.50 * 10-3 mol of aluminum sulfate?
Nonamiya [84]

Answer:

The mass is 0.855 grams (option A)

Explanation:

Step 1: Data given

aluminium sulfate = Al2(SO4)3

Numer of moles Al2(SO4)3 = 2.50 * 10^-3 moles

atomic mass Al = 26.99 g/mol

atomic mass S = 32.065 g/mol

Atomic mass O = 16 g/mol

Step 2: Calculate molar mass Al2(SO4)3

Molar mass = 2* 26.99 + 3*32.065 + 12*16

Molar mas = 342.175 g/mol

Step 3: Calculate mass Al2(SO4)3

Mass Al2(SO4)3 = moles Al2(SO4)3 * molar mass Al2(SO4)3

Mass Al2(SO4)3 = 2.5 *10^-3 moles * 342.175 g/mol

Mass Al2(SO4)3 = 0.855 grams

The mass is 0.855 grams (option A)

5 0
3 years ago
The following equation shows the equilibrium in an aqueous solution of ammonia: NH3(aq)+H2O(l)⇌NH4+(aq)+OH−(aq)NH3(aq)+H2O(l)⇌NH
yarga [219]

Answer:

c) H2O and OH−

Explanation:

Acids are the species which furnish hydrogen ions in the solution or is capable of forming bonds with electron pair species as they are electron deficient species.

When an acid donates a proton, it changes into a base which is known as its conjugate base.

Bases are the species which furnish hydroxide ions in the solution or is capable of forming bonds with electron deficient species as they are electron rich species. When a base accepts a proton, it changes into a acid which is known as its conjugate acid.

The acid and the base which is only differ by absence or presence of the proton are known as acid conjugate base pair.

Thus,  for the reaction,

NH_3+H_2O\rightleftharpoons Nh_4^++OH^-

The base is NH_3 and the conjugate acid of the base is NH_4^+.

Also, The base is OH^- and the conjugate acid of the base is H_2O.

<u>Correct option is :- c) H2O and OH−</u>

8 0
3 years ago
Depressants are often classified according to __________. Group of answer choices their MSA rating the degree to which they reac
daser333 [38]

Answer:

the degree to which they decrease CNS activity

Explanation:

Drugs can be classified as;

✓hallucinogens, example is (LSD)

✓ stimulants, example is (cocaine)

✓opium-related painkillers example is (heroin)

✓depressants

Depressants can be regarded as medicines, that lowers neurotransmission levels, that is depressing or reducing arousal or stimulation as regards to various areas of the brain. these could be tranquilizers, as well as hypnotics and

sedatives. They are drugs used in slowing brain activity, therefore, making them useful when treating anxiety, sleep disorders, panic and acute stress reactions.

Example of Depressants are;

✓Xanax

✓Halcion

✓Klonopin

✓Librium

It should be noted that Depressants are often classified according to the degree to which they decrease central nervous system (CNS) activity.

3 0
3 years ago
What physical or chemical properties would help identify a salt as containing a transition metal ion?
sasho [114]
Many transition metal ions(e.g. in soluble salt solutions) give colored hydroxide precipitates when mixed with aqueous sodium hydroxide solution. However zinc ions give a white hydroxide precipitate. These reactions can be used to help identify transition metal ions in solution.
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8 0
3 years ago
A(n)
alex41 [277]
It should be scientific law since a hypothesis is like a prediction and a theory could be used to explain something although it might not be true. There’s many theories just to explain one thing. So it should be scientific law
8 0
3 years ago
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