A corner test different weed killers on her along to see which kills the greatest number of dandelions............

the elements silicon (atomic number 14) and chlorine (atomic number 17) are both in period 3 of the periodic table. which is mor

Oliga [24]

Chlorine is highly reactive than Silicon.

7 0

4 years ago

Read 2 more answers

Perform the calculation and record the answer with the correct number of significant figures.

kotykmax [81]

The question is incomplete, here is the complete question:

A. (6.5-6.10)/3.19

B. (34.123 + 9.60) / (98.7654 - 9.249)

Answer:

For A: The answer becomes 0.1

For B: The answer becomes 0.4884

Explanation:

Significant figures are defined as the figures present in a number that expresses the magnitude of a quantity to a specific degree of accuracy.

Rules for the identification of significant figures:

Digits from 1 to 9 are always significant and have infinite number of significant figures.
All non-zero numbers are always significant. For example: 664, 6.64 and 66.4 all have three significant figures.
All zeros between the integers are always significant. For example: 5018, 5.018 and 50.18 all have four significant figures.
All zeros preceding the first integers are never significant. For example: 0.00058 has two significant figures.
All zeros after the decimal point are always significant. For example: 2.500, 25.00 and 250.0 all have four significant figures.
All zeroes used solely for spacing the decimal point are not significant. For example: 10000 has one significant figure.

Rule applied for addition and subtraction:

The least precise number present after the decimal point determines the number of significant figures in the answer.

Rule applied for multiplication and division:

In case of multiplication and division, the number of significant digits is taken from the value which has least precise significant digits

For A: (6.5-6.10)/3.19

This a a problem of subtraction and division.

First, the subtraction is carried out.

$\Rightarow \frac{6.5-6.10}{3.19}=\frac{0.4}{3.19}$

Here, the least precise number after decimal was 1.

$\Rightarrow \frac{0.4}{3.19}=0.125$

Here, the least precise number of significant digit is 1. So, the answer becomes 0.1

For B: (34.123 + 9.60) / (98.7654 - 9.249)

This a a problem of subtraction, addition and division.

First, the subtraction and addition is carried out.

$\Rightarow \frac{34.123+9.60}{98.7654-9.249}=\frac{43.723}{89.5164}=\frac{43.72}{89.516}$

Here, the least precise number after decimal in addition are 2 and in subtraction are 3

$\Rightarrow \frac{43.72}{89.516}=0.48840$

Here, the least precise number of significant digit are 4. So, the answer becomes 0.4884

6 0

3 years ago

All substances freeze at the same temperature, so they all have exactly the

Anastasy [175]

Answer:

I think it would be false

Explanation:

All things have a unique freezing/melting point

6 0

3 years ago

Assinale a alternativa incorreta. *

MakcuM [25]

Answer:

The incorrect choice is the last one:

In the Leucipo and Democritus atomic model, electrons had negative charges.

Explanation:

The translation of the question is:

Choose the incorrect statement. *

Matter is everything that has mass and occupies volume.

Mass and weight are different quantities. Mass is a measure of how much matter an object has, and weight is a measure of the gravitational pull force suffered by the object.

Dalton's atomic model has similarities to the atomic model described by Leucipo and Democritus.

Dalton thought that atoms of the same element could not combine, as they developed mutual repulsion.

In the Leucipo and Democritus atomic model, electrons had negative charges.

<h2>Solution</h2>

The last statement is false because Leucipo and Democritus thought that the atom was an indivisible particle. This is, they did not think there were subatomic particles, such as electrons. Furthermore, the idea of a particle with a negative charge was developed much time (centuries) later.

As for the other statements:

Matter is everything that has mass and occupies volume: this is the current definition of matter; for instance, wood, air, atoms, have mass and occupy volume. Thougths, feelings do not have either mass or occupy a volume, they are not matter.

Mass and weight are different quantities. Mass is a measure of how much matter an object has, and weight is a measure of the gravitational pull force suffered by the object. Indeed, the mass is determined by the number of atoms of the substance, but weight is the force of attraction from Earth (or other planet, if the object is in other planet). Mass does not change with the location; weight does.

Dalton's atomic model has similarities to the atomic model described by Leucipo and Democritus: sure. This is a hystorical question. Leucippus and Democritus were two Greek phylosophers who believed that the matter was formed by tiny solid particles, the atom.

Dalton thought that atoms of the same element could not combine, as they developed mutual repulsion. In the times of Dalton, when he developed the law of multiple proportions, atoms of a same kind were thought to repel each other.

3 0

3 years ago

Given the unbalanced equation below, answer the following: Calculate the number of liters of 3.00 M lead (II) iodide solution pr

mr_godi [17]

The number of liters of 3.00 M lead (II) iodide : 0.277 L

<h3>Further explanation</h3>

Reaction(balanced)

Pb(NO₃)₂(aq) + 2KI(aq) → 2KNO₃(aq) + PbI₂(s)

moles of KI = 1.66

From the equation, mol ratio of KI : PbI₂ = 2 : 1, so mol PbI₂ :

$\tt \dfrac{1}{2}\times 1.66=0.83$

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

$\large \boxed {\bold {M ~ = ~ \dfrac {n} {V}}}$

Where

M = Molarity

n = Number of moles of solute

V = Volume of solution

So the number of liters(V) of 3.00 M lead (II) iodide-PbI₂ (n=0.83, M=3):

$\tt V=\dfrac{n}{M}\\\\V=\dfrac{0.83}{3}\\\\V=0.277~L$

5 0

3 years ago