Answer:
the answer is b, 0.89
Explanation:
A cube has a height of 8 cm and a mass of 457 g. What is its density?
a. 233,984 g/cm
b. 0.89g/cm3
c. 1.12 g/cm3
Density = mass/volume
the volume of the cube is 8X8X8=512cm3
the mass is 457 gm
the density is 457/512 = 0.889 gm/cm3
the answer is b, 0.89
Given:
Iron, 125 grams
T
1 = 23.5 degrees Celsius, T2 =
78 degrees Celsius.
Required:
Heat produced in kilojoules
Solution:
The molar mass of iron is 55.8
grams per mole. SO we need to change the given mass of iron into moles.
Number of moles of iron = 125 g/(55.8
g/mol) = 2.24 moles
<span>
Q (heat) = nRT = nR(T2 = T1)</span>
Q (heat) = 2.24 moles (8.314
Joules per mol degrees Celsius) (78.0 degrees Celsius – 23.5 degrees Celsius)
<u>Q (heat) = 1014.97 Joules or
1.015 kilojoules</u>
<span>This is the amount of heat
produced in warming 125 g f iron.</span>
Answer:
82.4 s
Explanation:
Find the NUMBEr of half lives...then multiply by 54.3
2.27 = 6.5 (1/2)^n
log (2.27/6.5) / log (1/2) = n = 1.52 half lives
1.52 * 54.3 = 82.4 s
Answer:
Catalysts allow chemical reactions to occur at temperatures at which the organism lives.
Explanation:
Catalysts are molecules that speeden the rate of chemical reaction by lowering the activation energy of the reaction. In a living system, the catalyst are ENZYMES, which help to hasten up many biochemical reactions.
Another function of catalyst in living systems is that it allows chemical reactions to occur at temperatures at which the organism lives.
Answer:
Carbon dioxide reacts with limewater (a solution of calcium hydroxide, Ca(OH) 2), to form a white precipitate (appears milky) of calcium carbonate, CaCO 3.
Hope it helps you! :)
