7th grade science pls help

If 135.7 J of heat are added to 54.0 g of water initially at 25.0 °C . What is the final temperature of the water?

german

Answer:

The final temperature of the water is 25.6 °C.

Explanation:

We have,

Heat added to water is 135.7 J

Mass, m = 54 g

Initial temperature was 25 °C

It is required to find the final temperature of the water. The heat added when temperature is increased is given in terms of specific heat capacity as :

$Q=mc(T_f-T_i)$

$T_f$ is final temperature

c is specific heat capacity, for water, $c=4.184\ J/g^{\circ} C$

So,

$T_f=\dfrac{Q}{mc}+T_i\\\\T_f=\dfrac{135.7}{54\times 4.184}+25\\\\T_f=25.6^{\circ} C$

So, the final temperature of the water is 25.6 °C.

3 0

3 years ago

How many of the following molecules have sp2 hybridization on the central atom? hcn so2 ocl2 xecl2.

GrogVix [38]

Only one molecule have sp2 hybridization on central atom and that is SO₂.

XeCl₂ have sp3d hybridization.

OCl₂ have sp3 hybridization.

HCN have sp hybridization.

Hybridization is defined as the concept of mixing two atomic orbitals to give rise to a new type of hybridized orbitals.

Hybridization intermixing usually results in the formation of hybrid orbitals having entirely different energies, shapes, etc.

Learn more about hybridization here:- brainly.com/question/22765530

#SPJ4

7 0

1 year ago

Starting with 0.250L of a buffer solution containing 0.250 M benzoic acid (C 6H 5COOH) and 0.20 M sodium benzoate (C 6H 5COONa),

Zigmanuir [339]

Answer:

pH = 4.05

Explanation:

The pH of the benzoic buffer can be determined using H-H equation:

pH = pKa + log [A⁻] / [HA]

Where pKa is -logKa = 4.187

pH = 4.187 + log [Sodium Benzoate] / [Benzoic Acid]

Where [] can be understood as moles of each specie.

Thus, to find pH of the buffer we need to calculate moles of benzoic acid and sodium benzoate.

Initial moles:

Initial moles of benzoic acid and sodium benzoate are:

Acid: 250mL = 0.250L ₓ (0.250 moles / L) = 0.0625 moles of benzoic acid

Benzoate : 250mL = 0.20L ₓ (0.250 moles / L) = 0.050 moles of sodium benzoate

Moles after reaction:

Now, 0.0250L×(0.100mol/L) = 0.0025 moles of HCl are added to the buffer reacting with sodium benzoate, C₆H₅COONa, producing more benzoic acid, as follows:

HCl + C₆H₅COONa → C₆H₅COOH + NaCl

That means after reaction moles of both species are:

Benzoic acid: 0.0625 mol + 0.0025mol (Moles produced) = 0.065 moles

Sodium Benzoate: 0.050mol - 0.0025mol (Moles that react) = 0.0475 moles

Replacing in H-H equation:

pH = 4.187 + log [0.0475] / [0.065]

pH = 4.05

5 0

3 years ago

How is the scientific definition of "heat" different from how we use it every day? PLEASE NEED THE ANSWER ASAP

klio [65]

Heat is energy, that can be transferred to another item, which is “less hot”.

3 0

3 years ago

What Size container do you need to hold 0.0459 mol of N2 gas at stp

Allushta [10]

Hello!

You need to calculate the volume of the container. To calculate the volume of this amount of N₂ gas we need to make the assumption that N₂ behaves like an ideal gas.

1 mole of an ideal gas under Standard Temperature and Pressure occupies 22,4 L so the calculations are as follows:

$0,0459 mol N_2* \frac{22,4 L}{1 mol N_2}= 1,028 L$

So, the volume of the container should be 1,028 L or more.

Have a nice day!

4 0

3 years ago