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Ber [7]
3 years ago
8

I find that there are 500 atoms of U-235 and 1500 atoms of Pb-207. If we assume the mineral contained only parent and no daughte

r, then how many atoms of these elements were in the mineral when the rock first formed?
Chemistry
1 answer:
swat323 years ago
3 0

Explanation:

From the question it can be infered that initially only parent atoms were present in the rock and  no daughter atom. So, initially there was only uranium atom and no lead atom. So, in total there were 500+1500= 2000 uranium atom. And no lead tom was there.

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A student listed the characteristics of chemical and nuclear reactions.
lidiya [134]

Answer:

D. It is a chemical reaction because the total mass remains the same when new substances are formed.

Explanation:

A chemical reaction is represented by a chemical equation which show the reactant and products. Reactants are written on left side of arrow while products are written on right side. The number of atoms are remain same however arrangement of atoms is different on both side.

For example:

6H₂O + 6CO₂ + energy  →   C₆H₁₂O₆ + 6O₂

it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen. The number of atoms are same on both side however arrangement of atoms is different.

While in case of nuclear reaction small change in mass take place.

7 0
3 years ago
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A dam is used to retain water. Retaining water can also lead to flooding. Which most likely would be a new societal issue result
pantera1 [17]
Habitat destruction of the ecosystem.
5 0
3 years ago
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If one pound is the same as 454 grams, then convert the mass of 78 grams to pounds.
LiRa [457]

Answer:

0.17 lb

Explanation:

78 g * (1 lb/454 g)=0.17 lb

If you want additional help with chemistry or another subject for FREE, check out growthinyouth.org.

4 0
3 years ago
It has been suggested that the surface melting of ice plays a role in enabling speed skaters to achieve peak performance. Carry
vesna_86 [32]

Explanation:

Relation between pressure, latent heat of fusion, and change in volume is as follows.

          \frac{dP}{dT} = \frac{L}{T \times \Delta V}

Also, \frac{L}{T} = \Delta S^{fusion}_{m}

where, \Delta V^{fusion}_{m} is the difference in specific volumes.

Hence,    \frac{dP}{dT} = \frac{\Delta S^{fusion}_{m}}{\Delta V^{fusion}_{m}}

As, \Delta S^{fusion}_{m} = \frac{L}{T} = \frac{6010}{273.15} = 22.0 J/mol K

And,   \Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}} ...... (1)

where,    d_{H_{2}O} = density of water

              d_{ice} = density of ice

             M = molar mass of water = 18.02 \times 10^{-3} kg

Therefore, using formula in equation (1) we will calculate the volume of fusion as follows.

        \Delta V^{fusion}_{m} = \frac{M}{d_{H_{2}O}} - \frac{M}{d_{ice}}

                       = \frac{18.02 \times 10^{-3}}{997} - \frac{18.02 \times 10^{-3}}{920}  

                       = -1.51 \times 10^{-6}        

Therefore, calculate the required pressure as follows.

              \frac{dP}{dT} = \frac{22}{-1.51 \times 10^{-6}}

                              = 1.45 \times 10^{7} Pa/K

or,                           = 145 bar/K

Hence, for change of 1 degree pressure the decrease is 145 bar  and for 4.7 degree change dP = 145 \times 4.7 bar

                              = 681.5 bar

Thus, we can conclude that pressure should be increased by 681.5 bar to cause 4.7 degree change in melting point.

5 0
3 years ago
A beaker of water has a volume of 125mL and a density of 1.0g/mL. Calculate the mass of the water.​
Butoxors [25]

Answer:

125 g

Explanation:

D = m/v

1.0 g/mL = m /(125 mL)

125 g = m

6 0
3 years ago
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