The answers are
The age of the oldest stars
How fast distant galaxies are moving away from us
Patterns of background radiation.
Explanation:
The Astronomers calculate the age of the universe by looking for oldest stars, and by measuring the rate of expansion of the universe and back to big bang.
The Astronomers used the techniques like the age of oldest stars, how fast the distant galaxies are moving away from us, patterns of background radiation and along with the Big Bang as reference point, they estimate that the universe may be approximately 12 billion years old.
Answer:
Explanation: In my opinion law is stated as fact because it is passes through and approved by many peoples but theory is an idea someone has and is not approved and is set on a base of beliefs.
The heat of the reaction is an extensive property: it is proportional to the quantity of the quantity that reacts.
The change in enthalpy is a measured of the heat evolved of absorbed.
When the heat is released, the change in enthalpy is negative.
The reaction of 2 moles of Na develops 368.4 kj of energy.
Calculate the number of moles of Na in 1.90 g to find the heat released when this quantity reacts.
Atomic mass of Na: 23 g/mol
#mol Na = 1.90 g / 23 g/mol = 0.0826 mol
Do the ratios: [368.4 kj/2mol ] * 0.0826 mol = 15.21 kj.
Then the answer is that 15.21 kj of heat is released (evolved)
Answer:
196J, but C. at 200 J comes close.
Explanation:
Potential energy due to gravity is given by:
PEgrav = mass • g • height
where g is the acceleration due to gravity. We'll use 9.8 N/kg (on Earth).
PEgrav = mass • g • height
PEgrav = (2 kg) • (9.8 N/kg) • (10 m)
PEgrav = 196 N*m
1 N*m = 1 Joule
PEgrav = 196 J
C. at 200 J comes close. The solution probably used a value of g equal to 10 N/kg)
