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2 years ago

Cassidee walks 1-mile north and then turns and walks 2 miles west. Distance Displacement

Chemistry

1 answer:

Gemiola [76]2 years ago

4 0

Answer:

3 miles?

Explanation:

if you walk one mile North and then turn and walk another two miles you walk 3 miles and then turn around and walk back in the same direction you would end backup at the one-mile Mark he began. So three miles there two miles back

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What is radium used for

Bas_tet [7]

Answer:

Radium is used to produce Radon

Explanation:

Radon is a gas used to treat cancer (certain types).

6 0

3 years ago

Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin pla

RSB [31]

<u>Answer:</u> The enthalpy change of the reaction is -27. kJ/mol

<u>Explanation:</u>

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of water = 1 g/mL

Volume of water = 25.0 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{25.0mL}\\\\\text{Mass of water}=(1g/mL\times 25.0mL)=25g$

To calculate the heat released by the reaction, we use the equation:

$q=mc\Delta T$

where,

q = heat released

m = Total mass = [1.25 + 25] = 26.25 g

c = heat capacity of water = 4.18 J/g°C

$\Delta T$ = change in temperature = $T_2-T_1=(21.9-25.8)^oC=-3.9^oC$

Putting values in above equation, we get:

$q=26.25g\tiimes 4.18J/g^oC\times (-3.9^oC)=-427.9J=-0.428kJ$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of ammonium nitrate = 1.25 g

Molar mass of ammonium nitrate = 80 g/mol

Putting values in above equation, we get:

$\text{Moles of ammonium nitrate}=\frac{1.25g}{80g/mol}=0.0156mol$

To calculate the enthalpy change of the reaction, we use the equation:

$\Delta H_{rxn}=\frac{q}{n}$

where,

q = amount of heat released = -0.428 kJ

n = number of moles = 0.0156 moles

$\Delta H_{rxn}$ = enthalpy change of the reaction

Putting values in above equation, we get:

$\Delta H_{rxn}=\frac{-0.428kJ}{0.0156mol}=-27.44kJ/mol$

Hence, the enthalpy change of the reaction is -27. kJ/mol

4 0

3 years ago

Suppose that 0.48 g of water at 25 ∘ C condenses on the surface of a 55- g block of aluminum that is initially at 25 ∘ C . If th

mamaluj [8]

Answer:

$49^oC$

Explanation:

At $25^oC$ , the heat of vaporization of water is given by:

$\Delta H^o_{vap} = 43988 J/mol\cdot \frac{1 mol}{18.016 g} = 2441.6 J/g$

The water here condenses and gives off heat given by the product between its mass and the heat of vaporization:

$Q_1 = \Delta H^o_{vap} m_w$

The block of aluminum absorbs heat given by the product of its specific heat capacity, mass and the change in temperature:

$Q_2 = c_{Al}m_{Al}(t_f - t_i)$

According to the law of energy conservation, the heat lost is equal to the heat gained:

$Q_1 = Q_2$ or:

$\Delta H^o_{vap} m_w = c_{Al}m_{Al}(t_f - t_i)$

Rearrange for the final temperature:

$\Delta H^o_{vap} m_w = c_{Al}m_{Al}t_f - c_{Al}m_{Al}t_i$

We obtain:

$\Delta H^o_{vap} m_w + c_{Al}m_{Al}t_i = c_{Al}m_{Al}t_f$

Then:

$t_f = \frac{\Delta H^o_{vap} m_w + c_{Al}m_{Al}t_i}{c_{Al}m_{Al}} = \frac{2441.6 J/g\cdot 0.48 g + 0.903 \frac{J}{g^oC}\cdot 55 g\cdot 25^oC}{0.903 \frac{J}{g^oC}\cdot 55 g} = 49^oC$

6 0

3 years ago

What is a difference between ferns and gymnosperms?

Otrada [13]

Answer:

The answer is below!!

Explanation:

Ferns are plants that do not bear flowers. They do not have any seeds as well. In this regard, their mode of reproduction is through spores. Gymnosperms on the other hand have seeds, although they are not put inside an ovary.

Hope I Helped!!

7 0

2 years ago

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Write a letter to your friend describing your feelings after you left the school

fredd [130]

Dear friend,
How are you doing? I finally switched to my new school and it's been so hard adjusting. But I know I have a new chance at making new friends and memories. Also, I can learn new things, like interacting with new people and how to keep my anxiety low. I really miss us hanging out and how much we'd laugh and get in trouble at class. But i really hope to see you soon & that it hasn't gone terribly wrong for you since i left.
your friend,
name

8 0

3 years ago