2 years ago

Which of the following is an example of a chemical change?

Physics

1 answer:

tankabanditka [31]2 years ago

3 0

b. burning paper

hope it helps

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A 250 g block of ice is removed from the refrigerator at -8.0°C. How much thermal energy does the ice absorb as it warms to room

zlopas [31]

Answer:

Q = 114895 J

Explanation:

To find the thermal energy gained by the ice you use the following formula:

$Q=mc(T_2-T_1)+H_f\ m$

m: mass of the ice = 0.250kg

T2: final temperature = 22°C

T1: initial temperature = -8.0°C

Hf: heat of fusion of water = 3.34*10^5 J/kg

c: specific heat of water = 4186 J/kg

By replacing the values of the parameters you have:

$Q=(0.250kg)(4186J/kg\°C)(22+8)\°C+(3.34*10^5 J/kg)(0.250kg)\\\\Q=114895\ J$

where you have considered that ice melts completely

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3 years ago

Which statement is true about two isotopes of the same element?

scZoUnD [109]

Answer:

atoms that have the same # of protons but a DIFFERENT # of NEUTRONS

Explanation:

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3 years ago

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What type of motion occurs when an object spins around an axis without altering its linear position?

GarryVolchara [31]

That would be called Rotation

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3 years ago

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An astronaut holds a rock 100 m above surface of Planet X. The rock is then thrown upwards with a sleek of 15m/s. The rock reach

Gelneren [198K]

Answer: $5 m/s^{2}$

Explanation:

This problem is related to vertical motion, and the equation that models it is:

$y=y_{o}+V_{o}sin\theta t-\frac{1}{2}gt^{2}$ (1)

Where:

$y=0m$ is the rock's final height

$y_{o}=100 m$ is the rock's initial height

$V_{o}=15 m/s$ is the rock's initial velocity

$\theta=90\°$ is the angle at which the rock was thrown (directly upwards)

$t=10 s$ is the time

$g$ is the acceleration due gravity in Planet X

Isolating $g$ and taking into account $sin(90\°)=1$ :

$g=(-\frac{2}{t^{2}})(y-y_{o}-V_{o}t)$ (2)

$g=(-\frac{2}{(10 s)^{2}})(0 m-100 m-(15 m/s)(10 s))$ (3)

$g=5 m/s^{2}$ (4) This is the acceleration due gravity in Planet X

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2 years ago

Which statement best explains why elements are matter?

Lisa [10]

Choice D, as if it takes up mass then it is matter

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3 years ago