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antiseptic1488 [7]
3 years ago
5

#1: Which of the following is the abbreviation for a unit of energy? A. K / B. °C/ C. W / D. cal............... #2: A 200 g bloc

k of a substance requires 1.84 kJ of heat to raise its temperature from 25°C to 45°C. Use the table attached to identify the substance. A. iron/ B. aluminum/ C. gold/ D. copper.....................#3: In a calorimeter, the temperature of 100 g of water decreased by 10°C when 10 g of ice melted. How much heat was absorbed by the ice? A. 418 kJ / B. 100 kJ / C. 10 J / D. 4.18 kJ ..................#4: The amount of heat needed to raise the temperature of 50 g of a substance by 15°C is 1.83 kJ. What is the specific heat of the substance? A. 2.44 J/g-°C / B. 2.22 J/g-°C / C. 2.13 J/g-°C / D. 2.05 J/g-°C ................#5: In a calorimeter, 3.34 kJ of heat was absorbed when 10 g of ice melted. What is the enthalpy of fusion of the ice? A. 6.68 J/g / B. 334 J/g / C. 6.68 kJ/g/ D. 334 kJ/g
Chemistry
2 answers:
stealth61 [152]3 years ago
8 0
Among the choices, the unit of energy is calories. Answer in 1) is D. In 2) we are given with te mass , heat and temperature change. we just need to get the heat capacity and compare it with the following metals. The calculated heat capacity is 0.46 kJ/kg K. The answer is A. iron. In 3) we can compute the heat absorbed by the formula ΔH=mCpΔT. Cp of water is 4.18 J/g K. Answer of 3) is D. In 4) the formula used in Cp=ΔH/mΔT. Answer in 4) is A. The heat of enthalpy of fusion of ice is 80 cal/g. We convert this to J/g. Answer  in 5) is B.334 J/g.
Ivenika [448]3 years ago
7 0

Answer:

1. D. cal......

2.A. iron

3. D

4.2.44j/g°C   A

5,Lf=334J/g   B

Explanation:

1: Which of the following is the abbreviation for a unit of energy? A. K / B. °C/ C. W / D. cal...............

calorie is the unit of energy

#2: A 200 g block of a substance requires 1.84 kJ of heat to raise its temperature from 25°C to 45°C. Use the table attached to identify the substance. A. iron/ B. aluminum/ C. gold/ D. copper.....................

Q=mcdt

1840=0.2*C*(45-25)

C=460J/KgK

if the specific heat capacity is the above then he substance is iron

#3: In a calorimeter, the temperature of 100 g of water decreased by 10°C when 10 g of ice melted. How much heat was absorbed by the ice? A. 418 kJ / B. 100 kJ / C. 10 J / D. 4.18 kJ .................

Q=mcdT

Q=0.1*10*4180

Q=4180j. answer D

.#4: The amount of heat needed to raise the temperature of 50 g of a substance by 15°C is 1.83 kJ. What is the specific heat of the substance? A. 2.44 J/g-°C / B. 2.22 J/g-°C / C. 2.13 J/g-°C / D. 2.05 J/g-°C ................

Q=mcdT

1830=50/1000*C*15

C=2440j/kg/k

change it to j/g°C

2.44j/g°C   A

#5: In a calorimeter, 3.34 kJ of heat was absorbed when 10 g of ice melted. What is the enthalpy of fusion of the ice? A. 6.68 J/g / B. 334 J/g / C. 6.68 kJ/g/ D. 334 kJ/g

Q=mLf

Lf=enthalpy of fusion

3340/10=Lf

Lf=334J/g   B

Enthalpy of fusion quantity of heat to convert 1 unit mass of a solid to liquid without any noticeable change in temperature.

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madam [21]
1a. calcium chloride (CaCl2)
b. 2HCl (aq) + Ca(OH)2 (s) —> CaCl2 (aq) + 2H2O (l)

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7 0
3 years ago
Read 2 more answers
Convert 5.4g of NaCl to moles
sammy [17]

Answer:

.0924 moles of NaCl

Explanation:

So you know you have 5.4 g of NaCl and you need to know how many moles there are in this amount of NaCl

  1. You'll need to find the atomic mass of the compound NaCl to help you solve for moles
  • Sodium (Na) on the periodic table has a mass of 22.99
  • Chlorine (Cl) on the periodic table has a mass of 35.45

Add these two together----> 22.99 + 35.45 = 58.44

Now you can calculate for moles

<u>Written-out method:</u>

<u>5.4 grams of NaCl  |   1 mole of  NaCl              </u>

                                | 58.44 grams NaCl                = .0924 moles of NaCl

<u>Plug into calculator method:</u>

(5.4 g of NaCl/ 58.44g NaCl= .0925 moles)

7 0
3 years ago
What is a pollinator?
AlexFokin [52]

It's A: an animal that transfers pollen from flower to flower.

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8 0
3 years ago
Read 2 more answers
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DanielleElmas [232]

Explanation:

According to the law of conservation of mass, mass can neither be created nor destroyed but it can simply be transformed from one form to another.

For example, Na^{+} + Cl^{-} \rightarrow NaCl

Mass of Na = 23 g/mol

Mass of Cl = 35.5 g/mol

Sum of mass of reactants = mass of Na + mass of Cl

= 23 + 35.5 g/mol

= 58.5 g/mol

Mass of product formed is as follows.

Mass of NaCl = mass of Na + mass of Cl

= (23 g/mol + 35.5) g/mol

= 58.5 g/mol

As mass reacted is equal to the amount of mass formed. This shows that mass is conserved.

As a result, law of conservation of mass is obeyed.

3 0
3 years ago
1. A gas having the following composition is burnt under a boiler with 50% excess air.
jeka94

The composition of the stack gas are :

CH_4= 0.8713

C_3H_8 = 0.0202

CO = 0.107

<h3 /><h3>What is a mole fraction?</h3>

The ratio of the number of moles of one component of a solution or other mixture to the total number of moles representing all of the components.

Assuming 100 g of the stack gas. Calculate the mass of each species in this sample according to their percentages.

Mass of CH_4 : 70% of 100 g = 70 g

Mass of C_3H_8 : 15% of 100 g = 15 g

Mass of CO : 15% of 100 g = 15 g

Now calculate the number of moles of each species:

Number of moles of CH_4 : \frac{70 g}{16.04 g/mol} = 4.3 mole

Number of moles of C_3H_8: \frac{15 g}{144.1 g/mol} = 0.10 mole

Mass of CO : \frac{15 g}{28.01 g/mol} = 0.53 mole

Now to calculate the mole fraction of each we use the formula:

Mole fraction of CH_4: \frac{4.3}{4.935} = 0.8713

Mole fraction of C_3H_8 : \frac{0.10}{4.935} = 0.0202

Mole fraction of CO : \frac{0.53}{4.935} = 0.107

Hence, composition of the stack gas are:

CH_4 = 0.8713

C_3H_8 = 0.0202

CO = 0.107

Learn more about mole fraction here:

brainly.com/question/13135950

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