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2 years ago

How much heat is needed to change the temperature of 5g of water from 20 oC to 37 oC?

Chemistry

2 answers:

Dafna1 [17]2 years ago

5 0

Answer:

The answer to your question is Q = 355.64 J

Explanation:

Data

Heat = Q = ?

Temperature 1 = T1 = 20°C

Temperature 2 = T2 = 37°C

mass = m = 5 g

Specific heat = Cp = 4.184 J/g°C

Formula

Q = mCp(T2 - T1)

-Substitution

Q = (5)(4.184)(37 - 20)

-Simplification

Q = (5)(4.184)(17)

-Result

Q = 355.64 J

BabaBlast [244]2 years ago

4 0

The correct answer is 355.64 j

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Predict the products and write balanced net ionic equations for the following reactions. (g) SnCl2 is added to KMnO4 solution (a

ch4aika [34]

Answer:

The answer to your question is:

Explanation:

Reaction

SnCl₂ + 2KMnO₄ ⇒ 2 KCl + Sn(MnO₄)₂

1 ---- Sn ---- 1

2 ---- K ----- 2

2 ---- Mn ---- 2

8 ---- O ---- 8

2 ---- Cl ---- 2

6 0

2 years ago

A first-order reaction has a half-life of 16.7 s . How long does it take for the concentration of the reactant in the reaction t

andrew11 [14]

It takes 33.4 s for the concentration of A to fall to one-fourth of its original value.

A half-life is the time it takes for the concentration to fall to half its original value.

Assume the initial concentration is 1.00 mol/L. Then,

$\text{1.00 mol/L }\stackrel{\text{1st half-life }}{\longrightarrow}\text{ 0.50 mol/L } \stackrel{\text{ 2nd half-life }}{\longrightarrow}\text{0.25 mol/L}\\$

The concentration drops to one-fourth of its initial value in two half-lives.

∴ Time = 2 × 16.7 s = 33.4 s

5 0

2 years ago

A solution is made using 148.5 g of dimethyl ether (MM = 46.07 g/mol) and 90.0 g of methanol (MM = 32.04 g/mol). What is the mol

Mariulka [41]

Answer:

0.534

Explanation:

Mole fraction can be calculated using the formula:

Mole fraction = number of moles of solute ÷ number of moles of solvent and solute (solution).

In this question, solute is dimethyl ether while the solvent is methanol.

Mole (n) = mass (M) ÷ molar mass (MM)

Mole of solute (dimethyl ether) = 148.5 ÷ 46.07

= 3.22moles.

Mole of solvent (methanol) = 90 ÷ 32.04

= 2.81moles.

Total moles of solute and solvent = 3.22 + 2.81 = 6.03moles.

Mole fraction of dimethyl ether = number of moles of dimethyl ether ÷ number of moles of solution (dimethyl ether + methanol)

Mole fraction = 3.22/6.03

= 0.534

6 0

2 years ago

Write the net ionic equation for ammonium carbonate and lead(II) nitrate are combined. (Use the solubility rules provided in the

sashaice [31]

Answer: The net ionic equation is written below.

Explanation:

Net ionic equation of any reaction does not include any spectator ions.

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

The chemical equation for the reaction of ammonium carbonate and lead (II) nitrate is given as:

$(NH_4)_2CO_3(aq.)+Pb(NO_3)_2(aq.)\rightarrow 2NH_4NO_3(aq.)+PbCO_3(s)$

Ionic form of the above equation follows:

$2NH_4^{+}(aq.)+CO_3^{2-}(aq.)+Pb^{2+}(aq.)+2NO_3^{-}(aq.)\rightarrow PbCO_3(s)+2NH_4^+(aq.)+2NO_3^-(aq.)$

As, ammonium and nitrate ions are present on both the sides of the reaction. Thus, it will not be present in the net ionic equation and are spectator ions.

The net ionic equation for the above reaction follows:

$Pb^{2+}(aq.)+CO_3^{2-}(aq.)\rightarrow PbCO_3(s)$

Hence, the net ionic equation is written above.

8 0

2 years ago

Put the following steps in sequence to describe how chemical sedimentary rocks form ?

Natalka [10]

Answer: Option (D)

Explanation: Chemical weathering refers to the breakdown of minerals and forming new minerals due to the presence of chemical elements. For example, hydrolysis.

Due to the chemical weathering, initially, the minerals will get dissolved and are carried to the streams and oceans. After that, due to the saturation by water, the crystals will be precipitated out of that existing solution.

This crystals then sinks down to the bottom, forming sedimentary rocks.

Thus, the correct answer is option (D).

4 0

2 years ago