1. what is the pressure in space equal to? 2. what is the pressure in kPa at sea level?
3. a 15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature changes from 25°C to 175°C. Calculate the specific heat capacity of iron.
4. how many joules of heat are needed to raise the temperature of 10.0 g of aluminum from 22°C to 55°C, if the specific heat of aluminum is 0.90 J/g°C?

1. The pressure in outer space is so low that many consider it as non-existant. It has a pressure of 1.322 × 10−11 Pa. Pressure may be detected from the molecule of air or water hitting you. Since there is very little air and hardly ever water hitting you in space, pressure is almost zero or negligible.

2. Standard sea-level pressure, by definition, equals 760 mm (29.92 inches) of mercury, 14.70 pounds per square inch, 1,013.25 × 103 dynes per square centimetre, 1,013.25 millibars, one standard atmosphere, or 101.325 kilopascals.

3. 0.46J/gC

explanation.The specific heat capacity of a material is given by:

C_s = \frac{Q}{m \Delta T}C s = mΔTQ

where

Q is the amount of heat absorbedm is the mass

\Delta TΔT is the variation of temperature

For the piece of iron in the problem:

m = 15.75 gm=15.75g

Q=1086.75 JQ=1086.75J

\Delta T=175 C-25 C=150^{\circ}ΔT=175C−25C=150∘

Substituting into the equation,

C_s = \frac{1086.75 J}{(15.75 g)(150^{\circ}C)}=0.46 J/gCC s = (15.75g)(150 ∘ C)1086.75J = 0.46J/gC

4. 207 J

Explanation:

The key to this problem lies with aluminium's specific heat, which as you know tells you how much heat is needed in order to increase the temperature of 1 g of a given substance by 1∘C.

#I hope it's help

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"

answer; talc and gypsum;