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yarga [219]
3 years ago
9

A pacemaker:

Chemistry
1 answer:
inna [77]3 years ago
8 0
Answer: D. Sends small electrical impulses to the heart, causing it to beat more

Explanation: A pacemaker is implanted in the chest and helps to treat abnormal heart rhythms especially those causing your heart to skip beats or beat too slow.
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Washing soda, a compound used to prepare hard water for washing laundry, is a hydrate, which means that a certain number of wate
nadya68 [22]

Answer:

moles H₂O = 10

Explanation:

The mass of Na₂CO₃⋅xH₂O is 3.837 g and the mass of Na₂CO₃ is 1.42g

Therefore the mass of xH₂O is 3.837 - 1.42 = 2.417 g

The molar mass of Na₂CO₃ is 106 g/mol and for H₂O is 18 g/mol

The moles of Na₂CO₃ and H₂O in the sample are:

Na₂CO₃ = 1.42 / 106 = 0.01340 moles

H₂O = 2.417 / 18 = 0.1343

Now using rule of three :

1 mole of Na₂CO₃ has x moles of H₂O

0.01340 moles of Na₂CO₃ has 0.1343 moles of H₂O

x = 1 * 0.1343 / 0.01340 = 10

4 0
3 years ago
A certain compound is made up of one phosphorus (P) atom, three chlorine (Cl) atoms, and one oxygen (O) atom. What is the chemic
user100 [1]
<span> POCl3 is the correct way to write the chemical formula for this compound</span>
5 0
3 years ago
How many electron are in 56fe 3
RSB [31]
The periodic table is arranged in a way so that with each step the number of protons in the nucleus is increased by 1. It makes it for an easy choice to designate elements with numbers - atomic numbers, because in that case atomic number shows the number of protons possessed by the nucleus. Like this:
H has 1 proton
He has 2 protons
Li has 3 protons
Be has 4 protons and so on

Each proton has a charge of +1. The other particle present in the nucleus - the neutron - has zero electrical charge and thus irrelevant when computing the charge of a nucleus. It is easy to deduce that the nucleus charge equals the number of protons (which in turn equals the atomic number). So the nucleus charges are:
for H it's+1
for He it's +2
for Li it's +3
for Be it's +4 and so on

Atom is an electroneutral particle by definition. It means it's summed charge must be 0. Since we've looked at everything within the nucleus (the protons and the neutrons) it's time we turn our gaze to the space around it, which is full of orbiting electrons. Each electron has a charge of -1. To make up for the positive charge in the nucleus you have to fill the space aroung the nucleus with negative electrons.Thanks to the elementary nature of both proton and electron charge, you simply have to take the same number of electrons as that of protons! Like this:
H has 1 proton and 1 electron
He has 2 protons and 2 electrons
Li has 3 protons and 3 electrons
Be has 4 protons and 4 electrons and so on

Fe has atomic number 26. It means that Fe has 26 protons and 26 electrons. If it's a neutral atom

You typed 3. Is it accidental? If so, then the answer is above. If not, then you could be trying to type 56Fe +3, which means an ionic iron with charge +3. Charges are formed when you have too many or too few electrons to counter-balance the prositive charge of the nucleus. Charge +3 means you're 3 electrons short to negate the nucleus positive charge.

In other words, Fe+3 has 26 protons and 23 electrons.


7 0
3 years ago
Use the collision theory to explain how increasing the surface area of a solute will increase the rate of the dissolving process
Maksim231197 [3]
<span>More surface area --> more molecules of the solute in contact with the solvent --> more chance for a solvent molecule to collide with the solute molecules --> dissolves faster

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
</span>
5 0
3 years ago
You mix 200. mL of 0.400M HCl with 200. mL of 0.400M NaOH in a coffee cup calorimeter. The temperature of the solution goes from
GuDViN [60]

Answer : The enthalpy of neutralization is, 56.012 kJ/mole

Explanation :

First we have to calculate the moles of HCl and NaOH.

\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=0.400mole/L\times 0.200L=0.08mol

\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=0.400mole/L\times 0.200L=0.08mol

The balanced chemical reaction will be,

HCl+NaOH\rightarrow NaCl+H_2O

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.08 mole of HCl neutralizes by 0.08 mole of NaOH

Thus, the number of neutralized moles = 0.08 mole

Now we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = 200mL+200L=400mL

\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 400mL=400g

Now we have to calculate the heat absorbed during the reaction.

q=m\times c\times (T_{final}-T_{initial})

where,

q = heat absorbed = ?

c = specific heat of water = 4.18J/g^oC

m = mass of water = 400 g

T_{final} = final temperature of water = 27.78^oC=273+25.10=300.78K

T_{initial} = initial temperature of metal = 25.10^oC=273+27.78=298.1K

Now put all the given values in the above formula, we get:

q=400g\times 4.18J/g^oC\times (300.78-298.1)K

q=4480.96J

Thus, the heat released during the neutralization = -4480.96 J

Now we have to calculate the enthalpy of neutralization.

\Delta H=\frac{q}{n}

where,

\Delta H = enthalpy of neutralization = ?

q = heat released = -4480.96 J

n = number of moles used in neutralization = 0.08 mole

\Delta H=\frac{-4480.96J}{0.08mole}=-56012J/mole=-56.012kJ/mol

The negative sign indicate the heat released during the reaction.

Therefore, the enthalpy of neutralization is, 56.012 kJ/mole

8 0
3 years ago
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