The amount of substance present in a certain object with a given half-life in terms of h can be expressed through the equation,
A(t) = (A(o))(0.5)^(t/h)
where A(t) is the amount of substance after t years and A(o) is the original amount. In this item we are given that A(t)/A(o) is equal to 0.89. Substituting the known values,
0.89 = (0.5)(t / 5730 years)
The value of t from the equation is 963.34 years.
<em>Answer: 963 years</em>
Answer:
Adding heat.
Decreasing and increasing temperatures.
Explanation:
Answer:
the reactivity and the valence electrons
Explanation:
the reactivity of the elements would have played a significant role in why such elements were grouped together. the number of valence electrons dictates how reactive an element is - the less valence electrons the more reactive it is. the column, group 1 in which these elements are put together in, show that each of the elements have 1 valence electrons and are therefore reactive.
you can go on to further explain what valence electrons are, explain what the group numbers are associated with the valence electrons and how valence electrons effect reactivity. further this, talk about how the three elements have the same number of valence electrons and therefore were grouped together
Answer:Atomic theory established that all matter is made of tiny particles, a discovery that led to amazing scientific breakthroughs in areas from modern chemistry to nuclear energy.
Explanation:Atomic theory is the scientific theory that matter is composed of particles called atoms. Atomic theory traces its origins to an ancient philosophical tradition known as atomism.
61.24 is the molar mass of a gas which has a density of 0.00249 g/mL at 20.0 degrees celcius and 744.0 mm Hg.
Explanation:
given that:
density = 0.00249 g/ml (
) or 2.49 grams/litre
P = 744 mm Hg OR 0.978 atm
T = 20 Degrees or 293.15 Kelvin
R = 0.08206 Litre atm/mole K
molar mass =?
Formula used/
PV = nRT equation 1
here n is number of moles:
n = 
putting the value of n and value of density in the equation 1:
PV = 
x RT
molar mass = x 
= density x
= 
= 61.24 is the molar mass of the gas.
