Forms of a given element that have a different number of neutrons are called cosmic rays. True False

Jimmy is walking down the street and he notices that there is a small tree that has been uprooted from the ground. What two sphe

Nady [450]

Answer:

Explanation:,.....

8 0

3 years ago

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Which of the following substances (with specific heat capacity provided) would show the greatest temperature change upon absorbi

JulijaS [17]

Answer:

Pb is the substance that experiments the greatest temperature change.

Explanation:

The specific heat capacity refers to the amount of heat energy required to raise in 1 degree the temperature of 1 gram of substance. The highest the heat capacity, the more energy it would be required. These variables are related through the equation:

Q = c . m . ΔT

where,

Q is the amount of heat energy provided (J)

c is the specific heat capacity (J/g.°C)

m is the mass of the substance

ΔT is the change in temperature

Since the question is about the change in temperature, we can rearrange the equation like this:

$\Delta T = \frac{Q}{c.m}$

All the substances in the options have the same mass (m=10.0g) and absorb the same amount of heat (Q=100.0J), so the change in temperature depends only on the specific heat capacity. We can see in the last equation that they are inversely proportional; the lower c, the greater ΔT. Since we are looking for the greatest temperature change, It must be the one with the lowest c, namely, Pb with c = 0.128 J/g°C. This makes sense because Pb is a metal and therefore a good conductor of heat.

Its change in temperature is:

$\Delta T = \frac{q}{c.m} = \frac{100.0 J}{0.128 J/g.C . 10.0g } = 78.1$

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3 years ago

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A 125g metal block at a temperature of 93.2 degrees Celsius was immersed in 100g of water at 18.3 degrees Celsius. Given the spe

ivann1987 [24]

Answer:

Final temperature is 34.2 °C

Explanation:

Given data:

mass of metal = 125 g

temperature of metal = 93.2 °C

mass of water v= 100 g

temperature of water = 18.3 °C

specific heat of meta is = 0.900 j/g. °C

specific heat of water is = 4.186 j/g. °C

final temperature of water and metal = ?

Solution:

Q = m . c . ΔT

ΔT = T2-T1

now we will put the values in equation

Q1 = m . c . ΔT

Q1 = 125 g. 0.900 j/g. °C .93.2°C - T2

Q1 = 112.5 (93.2°C - T2)

Q1 =10,485 - 112.5T2

Q2 = m . c . ΔT

Q2 = 100 . 4.186. (T2- 18.3)

Q2 = 418.6 . (T2- 18.3)

Q2 = 418.6T2 - 7660.38

10,485 - 112.5T2 = 418.6T2 - 7660.38

10,485 + 7660.38 = 418.6T2+ 112.5T2

18145.38 = 531.1 T2

T2 = 18145.38/531.1

T2 = 34.2 °C

3 0

3 years ago

Calculate the reaction quotient Qp for the following redox reaction: 14H+ + Cr2O72- + 6Cl- ----> 2Cr3+ + 3Cl2 + 7H2O The reac

stich3 [128]

Answer:

Value of $Q_{p}$ for the given redox reaction is $1.0\times 10^{-8}$

Explanation:

Redox reaction with states of species:

$14H^{+}(aq.)+Cr_{2}O_{7}^{2-}(aq.)+6Cl^{-}(aq.)\rightarrow 2Cr^{3+}(aq.)+3Cl_{2}(g)+7H_{2}O(l)$

Reaction quotient for this redox reaction:

$Q_{p}=\frac{[Cr^{3+}]^{2}.P_{Cl_{2}}^{3}}{[H^{+}]^{14}.[Cr_{2}O_{7}^{2-}].[Cl^{-}]^{6}}$

Species inside third braket represent concentration in molarity, P represent pressure in atm and concentration of $H_{2}O$ is taken as 1 due to the fact that $H_{2}O$ is a pure liquid.