Question

Part 1 :

The mass of an average blueberry is 0.80g and the mass of an automobile is 1900kg.

Find the number of automobiles whose total mass is the same as 1.0mol blueberries.

Express your answer using two significant figures.

N =

Part 2 :

A household receives a $147 electricity bill. The cost of electricity is $0.123/kWh.

How much energy, in joules, did the household use?

Express your answer with the appropriate units.

Energy =

Answer 1

part 1 answer:

First conver the mass into Kg since automobile mass is given in Kg.

1) Mass of bluberry in kg

0.8g x 1kg/1000g = 0.0008 Kg

2) Now multiply this number by avogadro's number.(6.023x10^23) to calculate total mass

Total mass =0.0008 kg x 6.023x10^23 = 0.0048184x10^23 = 4.8184x10^20 Kg

3) So, total number of automobiles = Total mass/ mass of autombile

4.8184x10^20 Kg/1900Kg per automobile= 2.5347x10^17 automobiles

Part 2 answer:

Energy = electricity bill/cost of electricity

Energy = 147 / 0.123 kWhr = 1195 kWh.

1 kWhr = 1000 x 60 x 60 = 3600000 joule.

1195 kWhrs = 3600000 x 1195= 43020x10^5 joules =4.3020x10^9 joules

So, 4.3020x10^9 joules of energy is used in houshold use.