i need help

can anyone help me

Answer:

Two vectors are equal if they have the same magnitude and the same direction. Just like scalars which can have positive or negative values, vectors can also be positive or negative. A negative vector is a vector which points in the direction opposite to the reference positive direction.

Answer:

True? The don't stay exactly still i dont think, but i'd say true.

Explanation:

Answer:

TRUE

Explanation:

In a solid, atoms are packed tightly together and move very slowly. In fact, they do not flow at all: they simply vibrate back and forth.

Key words vibrate, not movement.

Correct me if I'm wrong of course

true  becouse i sed so                                            

Answer:

hope this help

Explanation:

change: volume of solid , volume of liquid , the volume of gases

not change: the shape of solid , the shape of liquid , the shape of gases

Answer:

0.0344 moles and 1.93g.

Explanation:

Molarity is defined as the ratio between moles of a solute (In this case, KOH), and the volume. With molarity and volume we can solve the moles of solute. With moles of solute we can find mass of the solute as follows:

Moles KOH:

15.2mL = 0.0152L * (2.26mol / L) = 0.0344moles

Mass KOH:

0.0344 moles * (56.11g/mol) = 1.93g of KOH

Answer:

A. p → ~q

Explanation:

I am double checking.

Answer:

6200 meters

Explanation:

To convert from km to m you have to multiply the number by a thousand

Answer:

6.2×10^3 m

Explanation:

6.20×1000=6200m

In scientific notation 6200 = 6.2×10^3

Answer:

It's false

Explanation:

Mixtures are always combinations of the same compounds that are at different states.

Answer:

each planet has a different force of gravity

Explanation:

Weight = mass× gravity

As gravity changes from place to place and also from planet to planet so weight changes.

Answer:

None have backbones

No cell walls

Multicellular

Includes radial or bilateral body symmetry.

Explanation:

Answer:

SO SORRY it took so long but the answer is B :)

Explanation:

Trust me and good luck :)

The theory that the planets move around the sun was endorsed by Aristarchus, Copernicus, as well as Galileo. The solar system revolves around the sun.

Aristarchus of Samos was just a Greek astronomer that suggested the very first heliocentric model of the cosmos, wherein the sun, rather than the earth, was even at its center. Despite the fact that his hypothesis was acknowledged by other philosophers of the time, it was dismissed as unrealistic, and the geocentric model remained in use for the next 1,700 years.

Copernicus was also the first to assert that the Earth as well as the other planets orbit the sun. It was really a significant shift in thinking.

Sun can be considered as a star in solar system.

The theory that the planets move around the sun was endorsed by Aristarchus, Copernicus, as well as Galileo. The solar system revolves around the sun.

Therefore, the correct answer will be option (b).

To know more about Aristarchus and Copernicus

https://brainly.com/question/12401405#SPJ2

AgCl⇒ the precipitate

Given

Reaction

2AgNO₃+CaCl₂⇒2AgCl+Ca(NO₃)₂

Required

The precipitate

Solution

Solubility rules :

soluble compound  :

All compounds of NO₃⁻ and C₂H₃O₂⁻

Compounds of Cl−, Br−, I− except Ag⁺, Hg₂²⁺, Pb²⁺

So AgCl⇒ the precipitate

Ca(NO₃)₂⇒aqueous

Answer:

[tex]PNCl_2[/tex]

Explanation:

Hello!

In this case, when determining empirical formulas by knowing the by-mass percent, we first must assume the percentages as masses so we can compute the moles of each element:

[tex]n_P=\frac{26.73g}{30.97g/mol}=0.863mol\\\\n_N=\frac{12.09g}{14.01g/mol}=0.863mol\\\\n_C_l=\frac{61.18g}{35.45g/mol}=1.726mol[/tex]

Now, for the determination of the subscript of each element in the empirical formula, we divide the moles by the fewest moles (P or N):

[tex]P=\frac{0.863mol}{0.863mol}=1\\\\N= \frac{0.863mol}{0.863mol}=1\\\\Cl=\frac{1.726mol}{0.863mol}2[/tex]

Thus, the empirical formula is:

[tex]PNCl_2[/tex]

Regards!

Answer: Alloy

Explanation: gold is an alloy, or mixture of metals

Answer:

[tex]6K _{(s)} + N _{2(g)} = = > \:2K _{3} N _{(s)} [/tex]

Potassium nitride

Answer:

50%

Explanation:

Let assume that there are:

"a" moles of CH4 & "b" moles of C2H2

Then by applying the ideal gas equation:

PV = nRT

[tex]16.8 \times 10^3 \times V = (a+b)RT[/tex]

Make (a+b) the subject of the formula:

[tex](a+b) = \dfrac{16800 \ V }{RT} mol[/tex] --- (1)

Since 1 mole of CH₄ yields 1 mol of CO₂ & 1 mol of C₂H₂ yields 2 moles of CO₂

Then;

the total moles of CO₂ = (a +2b)

Now:

[tex]25.3 \times 10^3 \times V = (a+ 2b)RT[/tex]

[tex](a + 2b) = \dfrac{25200 \ V}{RT \ mol}[/tex]    ---- (2)

∴

By solving the above equations

[tex]a = \dfrac{8400 \ V}{RT} \\ \\ b = \dfrac{8400 \ V}{RT}[/tex]

Hence, the estimate of the percentage of methane in the original mixture is:

[tex]= 100 \times \dfrac{a}{(a+b)}[/tex]

[tex]= 100 \times \dfrac{8400\dfrac{ \ V}{RT} }{8400\dfrac{ \ V}{RT} + 8400\dfrac{ \ V}{RT}}[/tex]

= 50%

Answer:

Specific heat capacity formula

Explanation:

The heat capacity gives the exact heat energy at which a given mass of a substance is heated from one temperature to another.

This formula can help determine how much heat is gained or lost during the reaction and is given by:

Q = mcΔT

where:

Q = heat energy in Joules or Calories

m - mass of the substance (g)

c = Specific heat capacity (J/kg°C)

ΔT = change in temperature = (final temp - initial temp) (°C)

I hope this was helpful.

Answer:

12

Explanation:

4x3 is 12

Answer:

To solve this simple expression you must substitute [tex]a[/tex] for the number you are given, so, 3.

4[tex]a[/tex] -> 4 3

Now, when numbers are next to each other like this, they are always multiplied. So, the find the answer you would multiply 4 times 3...

4 x 3 = 12

So, you answer will be 12!

Answer:

m=621.54g

Explanation:

number of moles= mass of H2O/molar mass of H2O

n=m/mm

make mass the subject of the formula

m=n*mm

find molar mass of water

H2O=1(16)+2(1)

mm= 18.0g/mol. n=34.53mol

hence, m=34.53mol*18.0g/mol

m=621.54g

Answer: The mole fraction of chloroform in this solution is 0.41

Explanation:

To calculate the moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}[/tex]

a) moles of [tex]CHCl_3[/tex]

[tex]\text{Number of moles}=\frac{49g}{119g/mol}=0.41moles[/tex]

b) moles of [tex]CH_3COBr[/tex]

[tex]\text{Number of moles}=\frac{73g}{123g/mol}=0.59moles[/tex]

To calculate the mole fraction, we use the formula:

[tex]\text{Mole fraction of a component}=\frac{\text{Moles of the component}}{\text{total moles}}[/tex]

[tex]\text{Mole fraction of chloroform}=\frac{\text{Moles of chloroform}}{\text{total moles}}=\frac{0.41}{0.41+0.59}=0.41[/tex]

The mole fraction of chloroform in this solution is 0.41

Answer:

Explanation:

p-diaminobenzene is popularly known as p-phenylenediamine. It undergoes a condensation reaction with metal halides. As a white solid (p-diaminobenzene), it can be darkened by air oxidation. The reaction showing the condensation of p-phenylenediamine with (CoCl)₂ can be seen in the image attached below.

Explanation:

hope it helps you

Answer:

Grass

Oak tree

Explanation:

Bear and human are definitely not and fungus are decomposers.

Answer:

36 electrons

Explanation:

The # of protons is always equal to the atomic number. In the case of Sr (Strontium), it is 38 protons.

The 2+ at the end means that it has a charge of +2, meaning that it LOST two electrons to become a cation with a full valence shell. So, 38 - 2 = 36 electrons

Answer:

38 protons 36 electrons 30 neutron because of 29 isotope

Answer:

True

Explanation:

Answer:

Electronegativity is probably the biggest thing that plays into reactivity. Therefore, since fluorine has a higher electronegativity than chlorine, fluorine is more reactive.

Explanation:

I got it right

Answer:

Hydrogen chloride (HCl) and Calcium hydroxide (CaOH). (see balanced equation below)

Explanation:

In a neutralization reaction as is the case of the question (see attachment), an acid would be neutralized by a base to form salt and water.

The most plausible reactants for the reaction given the number of moles of the product, is therefore Hydrogen chloride (HCl) and Calcium hydroxide (Ca(OH)2).

[tex]HCl _{(aq)} + Ca(OH)_{2} _{(aq)}[/tex] →[tex]CaCl_{2}_{(s)} + H_{2} O_{(l)}[/tex]

Let me know if this was helpful.

Answer:

Because the compound has a formula of M2O, the number of valence electrons of M should be 1. Therefore, (1) Group 1 is the correct answer because elements in group 1 have 1 valence electron.

Explanation:

Answer:

[tex]4.86\times10^{-7}\ \text{m}[/tex]

Explanation:

R = Rydberg constant = [tex]1.09677583\times 10^7\ \text{m}^{-1}[/tex]

[tex]n_1[/tex] = Principal quantum number of an energy level = 2

[tex]n_2[/tex] = Principal quantum number of an energy level for the atomic electron transition = 4

Wavelength is given by the Rydberg formula

[tex]\lambda^{-1}=R\left(\dfrac{1}{n_1^2}-\dfrac{1}{n_2^2}\right)\\\Rightarrow \lambda^{-1}=1.09677583\times 10^7\left(\dfrac{1}{2^2}-\dfrac{1}{4^2}\right)\\\Rightarrow \lambda=\left(1.09677583\times 10^7\left(\dfrac{1}{2^2}-\dfrac{1}{4^2}\right)\right)^{-1}\\\Rightarrow \lambda=4.86\times10^{-7}\ \text{m}[/tex]

The wavelength of the light emitted is [tex]4.86\times10^{-7}\ \text{m}[/tex].