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laiz [17]
2 years ago
7

1. How much heat (in calories) is needed to raise 20 g of H2O from 5°C to 40°C? (c = 1.0 cal/g °C)

Chemistry
1 answer:
KIM [24]2 years ago
6 0

Answer:

700 calories

Explanation:

Using the formula below:

Q = m × c × ∆T

Where;

Q = amount of heat required (calories)

m = mass of substance (g)

c = specific heat of substance (cal/g°C)

∆T = change in temperature (°C)

According to this question, the following information was provided;

Q = ?

m = 20g

c = 1.0 cal/g °C

∆T = 40°C - 5°C = 35°C

Using the formula; Q = m × c × ∆T

Q = 20 × 1 × 35

Q = 700 calories

Hence, 700 cal of heat energy is needed to raise 20 g of H2O from 5°C to 40°C.

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Zinc is used as a coating for steel to protect the steel from environmental corrosion. If a piece of steel is submerged in an el
sweet [91]

Answer:

A) 3.17 g of Zn

Explanation:

Let's consider the reduction of Zn(II) that occurs in an electrolysis bath.

Zn⁺²(aq) + 2e⁻ → Zn(s)

We can establish the following relations:

  • 1 min = 60 s
  • 1 A = 1 C/s
  • The charge of 1 mole of electrons is 96,468 C (Faraday's constant).
  • When 2 moles of electrons circulate, 1 mole of Zn is deposited.
  • The molar mass of Zn is 65.38 g/mol

The mass of Zn deposited under these conditions is:

24min \times \frac{60s}{1min} \times \frac{6.5C}{s} \times \frac{1mol\ e^{-} }{96,468C} \times \frac{1molZn}{2mol\ e^{-}}  \times \frac{65.38g}{1molZn} = 3.17 g

3 0
3 years ago
must undergo addition because they have easily broken π bonds. ____________ rule states in the addition of HX to an unsymmetrica
erastova [34]

Answer:

Alkenes, Markovnikov's, Alkenes, Alkyl halides, and less.

Explanation:

Alkenes must undergo addition because they have easily broken π bonds.

Markovnikov's rule states in the addition of HX to an unsymmetrical alkene, the H atom bonds to the less substituted carbon atom.

Alkenes are unsaturated hydrocarbons because they have fewer than the maximum number of hydrogen atoms per carbon.

Alkyl halides have good leaving groups and therefore readily undergo substitution and elimination reactions.

In hydroboration, the boron atom bonds to the less substituted carbon.

3 0
3 years ago
A pendulum has 534 J of potential energy at the highest point of its swing. How much kinetic energy will it have at the bottom o
butalik [34]
Do you got the answer with you or do u have to work them out to get the answer

4 0
2 years ago
Calculate the number of gold atoms in a sample of gold(III) chloride . Be sure your answer has a unit symbol if necessary, and r
Fudgin [204]

Answer: N = 2.78 × 10^23 atoms

There are N = 2.78 × 10^23 atoms in 70g of Au2cl6

Completed Question:

Calculate the number of gold atoms in a 70g sample of gold(III) chloride . Be sure your answer has a unit symbol if necessary, and round it to significant digits

Explanation:

Given:

Molar mass of Au2cl6 = 303.33g/mol

Mass of Au2cl6 = 70g

Number of moles of Au2cl6 = 70g/303.33g/mol = 0.231mol

According to the chemical formula of Au2cl6,

1 mole of Au2cl6 contains 2 moles of Au

Number of moles of Au = 2 × 0.231mol = 0.462mole

There are 6.022 × 10^23 atoms in 1 mole of an element.

Number of Atom of gold in 0.462 mole of gold is:

N = 0.462 mol × 6.022 × 10^23 atoms/mol

N = 2.78 × 10^23 atoms

7 0
3 years ago
3. Write DISSOCIATION or IONIZATION equations for the following chemicals:
Romashka [77]

Answer:

a) HNO3 -> H+ + NO3- disassociation of Nitric Acid; to yield a Nitrate ion and a Proton, H+, or as a Hydronium ion H3O+

b) H2S04 -> Disassociation of Sulfuric Acid; simple way- 2H+ + SO4- -

c) H2S hydrogen sulphide in water is an acid; thus H+ HS- disassociation.

d) NaOH -> dissociation of Na+ + OH-; this is complete; sodium hydroxide is deliquescent, meaning it will draw water - EVEN from the air! Strong Base

e) Na2CO3 -> 2Na+ CO3- - Ionization of sodium carbonate - a salt

f) Na2S04 -> 2Na+ + SO4 - - ionization of sodium sulphate - a salt

g) NaCl​ -> Na+ + Cl- ionization of the salt, Sodium Chloride

Explanation:

Salts ionize at different rates; acids or bases dissociate; these are mostly strong acids and NaOH, a strong base.

8 0
3 years ago
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