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Ymorist [56]
2 years ago
9

A student has a block of wood. She places it on a wooden desk. She uses a spring scale to measure how much force is needed to sl

ide the block of wood across the desk. The student then places the block of wood on a piece of sandpaper and repeats the process. The type of force
the student is investigating is _______.

A. gravitational
B. magnetic
C. electricity
D. friction
Chemistry
2 answers:
yarga [219]2 years ago
6 0
D:friction



Reason:because they are trying different types of things to rub against it and see if it will slow it down



Please give me the bran list answer !
Firdavs [7]2 years ago
4 0
D: i know this is correct not much behind that tho
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What is the viscosity and flammability of refinery gas?
Liono4ka [1.6K]
Hydrocarbons

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6 0
3 years ago
Does data from mass spectrometry indicate that modern scientists have made modifications to Dalton''s model? Justify.
Gelneren [198K]
John Dalton was a scientist who proposed that all matter consists of atoms. At this stage, no one had yet discovered neutrons and the nucleus. As a result, Dalton's model consisted of a single atom i.e. the atom was the smallest object. 
A mass spectrometer is an instrument that is able to see what is inside an atom. Scientists have been able to prove that the item is not the smallest object in the world. Atoms are made up of smaller objects called protons, neutrons and electrons. 
We can, therefore, safely conclude that data  from mass spectrometry has helped modern scientists to make modifications to Dalton's model. <span>
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5 0
3 years ago
How many moles are in 15.0 grams of calcium (Ca)?
borishaifa [10]
1 mol ---- 40g
X --------- 15g
X = 15/40 = 0,375 moles

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5 0
3 years ago
Read 2 more answers
What is the mass of an element with 15 protons, 13 electrons, and 11 neutrons? *
RSB [31]

Answer:

The mass of the element is 26.20 amu

Explanation:

In this question, we are asked to calculate the mass of an element with 15 protons, 13 electrons and 11 neutrons

To calculate the atomic mass of the element, we take into consideration the masses of the individual sub atomic particles

Electrons have 0 atomic mass unit(their masses are negligible) we have no business here, Protons have a mass of

1.00727647 amu, while the mass of neutron is 1.0086654 amu

The mass of 15 protons is thus 15 * 1.00727647 = 15.10914705 amu

The mass of 11 neutrons is 11 * 1.0086654 =

11.0953194 amu

Adding this together, we have ; 11.0953194 + 15.10914705 = approximately 26.20 amu

6 0
3 years ago
A reaction of importance in the formation of smog is that between ozone and nitrogen monoxide described by O 3 ( g ) + NO ( g )
Aleksandr [31]

Answer:

(a) 7.11x10⁻⁴ M/s

(b) 2.56 mol.L⁻¹.h⁻¹

Explanation:

(a) The reaction is:

O₃(g) + NO(g) → O₂(g) + NO₂(g)   (1)

The reaction rate of equation (1) is given by:

rate = k*[O_{3}][NO]     (2)

<u>We have:</u>

k: is the rate constant of reaction = 3.91x10⁶ M⁻¹.s⁻¹

[O₃]₀ = 2.35x10⁻⁶ M

[NO]₀ = 7.74x10⁻⁵ M

Hence, to find the inital reacion rate we will use equation (2):

rate = k*[O_{3}]_{0}[NO]_{0} = 3.91 \cdot 10^{6} M^{-1}s^{-1}*2.35\cdot 10^{-6} M*7.74 \cdot 10^{-5} M = 7.11 \cdot 10^{-4} M/s  

Therefore, the inital reaction rate is 7.11x10⁻⁴ M/s

(b) The number of moles of NO₂(g) produced per hour per liter of air is:

t = 1 h

V = 1 L

\frac{\Delta[NO_{2}]}{\Delta t} = rate

\frac{\Delta[NO_{2}]}{\Delta t} = 7.11 \cdot 10^{-4} M/s*\frac{3600 s}{1 h} = 2.56 mol.L^{-1}.h{-1}

Hence, the number of moles of NO₂(g) produced per hour per liter of air is 2.56 mol.L⁻¹.h⁻¹

I hope it helps you!                                

5 0
3 years ago
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