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Ratling [72]
2 years ago
11

Help pleaseeeeeeeee just need 4 answers

Chemistry
1 answer:
larisa86 [58]2 years ago
8 0

Answer:

Here, acceleration due to gravity(a) is assumed as 10m/s².We can also take it as 9.8m/s²

Explanation:Brick) Weight=m * a=1 * 10=10N\\Bag of books) Mass=f/a=25/10=2.5kg\\Bag of potatoes) Weight=m * a=10 * 10=100N\\Bag of cement) Mass=f/a=400/10=40kg

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2. Which of the following elements does not lose an electron easily? (a) Na (6) F (c) Mg (d) Al​
vaieri [72.5K]

Answer:

Answer: (b) F

Explanation:

Sodium has 1, magnesium has 2 and Aluminium has 3 electrons in its outermost shell whereas Fluorine has 7 electrons in its outermost shell hence Fluorine does not lose electrons easily.

The electronic configuration of fluorine is 2,7.

Fluorine is the ninth element with a total of 9 electrons.

The first two electrons will go in the 1s orbital.

The next 2 electrons for F go in the 2s orbital.

The remaining five electrons will go in the 2p orbital. Therefore the F electron configuration will be 1s22s22p5.

3 0
2 years ago
What is an exotoxin?
Elodia [21]
Exotoxin is a toxin secreted by bacteria. exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism
8 0
3 years ago
In determining the energy of activation, why was it prudent to run the slowest trial done at room temperature in the hot water b
Katen [24]

Answer:In determining the energy of activation, why was it prudent to run the slowest trial done at room temperature in the hot water bath and the fastest trial done at room temperature in the cold water bath?

Explanation:

4 0
2 years ago
Lead(II) oxide from an ore can be reduced to elemental lead by heating in a furnace with carbon. Calculate the expected yield of
Lelu [443]

Answer:

53kg is the expected yield of lead

Explanation:

Firstly, in order to solve this question, we need to write the equation of reaction correctly. This is as follows:

PbO(s) + C(s) ---> Pb(l) + CO(g)

We proceed from here. We should get the limiting reactant but this can only be obtained by getting the number of moles of each reactant present.

The formula to use across all boards is that the number of moles is the mass of each of the reactant divided by the molar mass of each of the reactant.

For PBO, mass is 57kg = 57000g

Molar mass of PBO = 223.20g/mol

The number of moles is thus 57,000/223.2 = 255.37 moles

For carbon, mass is also 57kg = 57000g

Molar mass is 12g/mol

Number of moles of carbon = 57000/12 = 4750 moles

From the number of moles, we can see that the number of moles of Carbon is greater than that of PbO. This means that PbO is the limiting reagent.

Hence we use it to calculate percentage yield.

The number of moles of lead formed is the same of number of moles of lead oxide = 255.37 since we have mole ratio of 1 to 1

The molar mass of lead is 207.20g/mol

The mass of lead formed is = moles of lead formed * molar mass of lead = 207.20 * 255.37 = 52,912g which is approximately 53kg

Hence the expected yield is 53kg

6 0
3 years ago
A 40.0 mL sample of 0.18 M HCI is titrated with 0.36 M CoHsNH2. Dctermine the pH at these points: At the beginning (before base
Whitepunk [10]

Answer:

at the beginning:

pH = 0.745

Explanation:

HCl is a strong acid, so:

  • HCl + H2O  → H3O+  +  Cl-

       0.18 M             0.18        0.18.....equilibrium

before base is added:

∴ [ H3O+ ] ≅ <em>C </em>HCl = 0.18 M

⇒ pH = - Log [ H3O+ ] = - Log ( 0.18 )

⇒ pH = 0.745

8 0
3 years ago
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