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3 years ago

Solve you will get brainliest and23 points

Chemistry

2 answers:

timurjin [86]3 years ago

4 0

It’s the second one if you need more help tell me

Galina-37 [17]3 years ago

4 0

Yes it is the second one

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A teacher gives her students a small aluminum cube. She shows them a table that has a list of properties of the cube. The table

Mkey [24]

The answer is B.mass because like the periodic table it determines the elements by mass

6 0

3 years ago

2.70g of Zn (s) reacts with 50.0 mL of 1.00 M HCl solution to produce hydrogen gas according to the reaction. (R = 0.08206 L·atm

Anika [276]

Answer:

a. 0.0413 moles Zn

b. 0.0500 moles HCl

c. HCl is the limiting reactant

d. 0.0250 moles H₂

e. V = 0.56L

Explanation:

The reaction of Zn(s) with HCl is:

Zn(s) + 2HCl (aq) → ZnCl₂ (aq) + H₂(g)

Where 1 mole of Zn reacts with 2 moles of HCl.

a) To convert mass in grams to moles of a substance you need to use molar mass (Molar mass Zn: 65.38g/mol), thus:

2.70g Zn × (1mol / 65.38g) = 0.0413moles of Zn

b. Now, when you have a solution in molarity (Moles / L), you can know the moles of a volume of solution, thus:

Moles HCl:

50.0mL = 0.0500L × (1.00mol / L) = 0.0500 moles HCl

c. The limiting reactant is founded by using the chemical reaction as follows:

For a complete reaction of 0.0500 moles HCl you need:

0.0500 moles HCl × (1 mole Zn / 2 moles HCl) = 0.0250 moles Zn

As you have 0.0413 moles of Zn, and you need just 0.0250 moles for the complete reaction, Zn is the exces reactant and HCl is the limiting reactant

d.As HCl is limiting reactant and 2 moles of HCl react with 1 mole of H₂, moles of hydrogen formed are:

0.0500 moles HCl × (1 mole H₂ / 2 moles HCl) = 0.0250 moles H₂

e. Using PV = nRT, you can find volume of gas, thus:

PV = nRT

V = nRT / P

Where P is pressure 1atm at STP, n are moles, R is gas consant 0.08206Latm/molK and T is absolute temperature 273.15K at STP.

V = 0.0250molesₓ0.082atmL/molKₓ273.15K / 1atm

V = 0.56L

3 0

3 years ago

Aquafers are bodies of water found above ground with thriving ecosystems. O True O False

tekilochka [14]

False.

Aquifers are actually underground! The water from this water-bearing permeable rock is used in wells. Here’s a chart (sorry for the sloppiness).

5 0

3 years ago

When a solution of ammonium chloride, NH4Cl, is added to a solution of lead (II) nitrate , Pb(NO3)2, a white precipitate, PbCl2,

slavikrds [6]

Answer:

B) $2NH_4^+_{(aq)}+2Cl^-_{(aq)}+Pb^{2+}_{(aq)}+2NO_3^-_{(aq)}\rightarrow PbCl_2_{(s)}+2NH^{4+}_{(aq)}+2NO_3^-_{(aq)}$

Explanation:

The total ionic equation contains all the species in the reaction in the ionic form.

Spectator ions are defined as the ions which does not get involved in a chemical equation or they are ions which are found on both the sides of the chemical reaction present in ionic form.

Spectator ions are also written in total ionic equations.

The chemical equation is:

$2NH_4Cl_{(aq)}+Pb(NO_3)_2_{(aq)}\rightarrow PbCl_2_{(s)}+2NH_4NO_3_{(aq)}$

The total ionic equation is -

$2NH_4^+_{(aq)}+2Cl^-_{(aq)}+Pb^{2+}_{(aq)}+2NO_3^-_{(aq)}\rightarrow PbCl_2_{(s)}+2NH^{4+}_{(aq)}+2NO_3^-_{(aq)}$

5 0

4 years ago

What is the pH of a 1.288 M solution of sodium acetate? Ka of acetic acid is 1.8*10^-5. (2 decimal places)

Shtirlitz [24]

Answer:

The pH of the solution is 9.43

Explanation:

sodium acetate = CH3COONa

after removing the spectator ion Na

CH3COO⁻ + H2O ⇄ CH3COOH + H3O⁺

since sodium acetate is a weak base, it will not react completely with water. Thus a value "x" will be used to make the products.

At equilibrium:

[CH3COO⁻] = 1.288 - x

[CH3COOH] = x

[H3O⁺] = x

Since a base is reacting with H2O, Kb is used at equilibrium: Kb=(1*10^-14)/(1.8*10^-5) = 5.6*10^-10)

Kb = [CH3COOH][H3O⁺]/[CH3COO⁻]

Kb = (x²)/(1.288-x) since the Kb is significantly lower than 1.288 we can make a mathematical assumption that x is significantly lower than 1.288.

5.6*10⁻¹⁰ = x²/1.288

x = [OH⁻] = 2.675*10⁻⁵ M

pOH = -log[OH⁻] = 4.57

pH=14-pOH = 14 - 4.57 = 9.43

4 0

3 years ago