Answer:
c = 4016.64 j/g.°C
Explanation:
Given data:
Mass of substance = 2.50 g
Calories release = 12 cal (12 ×4184 = 50208 j)
Initial temperature = 25°C
Final temperature = 20°C
Specific heat of substance = ?
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
Solution:
Q = m.c. ΔT
ΔT = T2 - T1
ΔT = 20°C - 25°C
ΔT = -5°C
50208 j = 2.50 g . c. -5°C
50208 j = -12.5 g.°C .c
50208 j /-12.5 g.°C = c
c = 4016.64 j/g.°C
So you have a balloon rising through the atmosphere. use the formula p1/v1=p2/v2 and add the variables into the equation, leaving 295/52.5=252/x. multiply 252 by 52.5 and divide that number by 295.
52.5*252=13230. divide by 295 =44.9 L
Answer:
8.8g of Al are necessaries
Explanation:
Based on the reaction, 2 moles of Al are required to produce 3 moles of hydrogen gas.
To solve this question we must find the moles of H2 in 11L at STP using PV = nRT. With these moles we can find the moles of Al required and its mass as follows:
<em>Moles H2:</em>
PV = nRT; PV/RT = n
<em>Where P is pressure = 1atm at STP; V is volume = 11L; R is gas constant = 0.082atmL/molK and T is absolute temperature = 273.15K at STP</em>
Replacing:
1atm*11L/0.082atmL/molK*273.15K = n
n = 0.491 moles of H2 must be produced
<em />
<em>Moles Al:</em>
0.491 moles of H2 * (2mol Al / 3mol H2) = 0.327moles of Al are required
<em />
<em>Mass Al -Molar mass: 26.98g/mol-:</em>
0.327moles of Al * (26.98g / mol) = 8.8g of Al are necessaries
Answer:
Significant figures are a measure of <u><em>precision</em></u>.
Explanation:
The significant figures of a number are those that have a real meaning and, therefore, provide some information. Therefore, the set of digits that are known with certainty in a measure are called significant figures and are the digits of a number considered non-null.
Any experimental measurement is inaccurate and must be expressed with its significant figures.
In this way, significant figures express the precision of a measuring tool.
I believe your answer is correct. A) Solar Cell
