what is the mass of a sample of glass (specific heat = 0.50 J/g°C), if it requires 490 J of heat to raise the temperature from -18.0°C to 0.0°C?

54.4g

Explanation:

Let's first take account of what we have and what we're looking for.

Q = heat energy (Joules, J)= 490 J

m = mass of a substance= ??

c = specific heat (units J/kg∙K)= 0.50 J/g°C

∆T = change in temperature (Kelvins, K)= Final temperature - initial temperature -> (0C - (-18C))

We can use Q = mc∆T to determine the mass, we'll rearrange the formula to solve for mass, so it'll be: m=Q/c∆T. Let's plug it all in.

m= 490J / (0.50 J/g°C x ((0C - (-18C)))

m= 490J / (0.50 J/g°C x (0 + 18))

m=  490J / (0.50 J/g°C x 18)

m= 490J / 9 J/g

m= 54.4g of glass

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.